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University Microfilms International 300 N. Zeeb Road Ann Arbor, Ml 48106 8507503 H usin, Zulkifli DEMAND, SUPPLY AND BIOECONOMIC ANALYSIS OF A REPLENISHABLE RESOURCE: A STUDY OF MICHIGAN’S GREAT LAKES COMMERCIAL FISHERY Ph.D. Michigan State University University Microfilms International 300 N. Zeeb Road, Ann Arbor, Ml 48106 Copyright 1985 by Husin, Zulkifli All Rights Reserved 1984 PLEASE NOTE: In all cases this material h as been filmed in the best possible way from the available copy. Problems encountered with this docum ent have been identified here with a ch eck mark V 1. Glossy photographs or p a g e s _____ 2. Colored illustrations, paper or print______ 3. Photographs with dark background 4. Illustrations are poor copy______ 5. Pages with black marks, not originai co p y ______ 6. Print shows through as there is text on both sides of p a g e _______ 7. Indistinct, broken o r small print on several pages 8. Print exceeds margin requirem ents______ 9. 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University Microfiims International DEMAND, SUPPLY AND BIOECONOMIC ANALYSIS OF A REPLENISHABLE RESOURCE: A STUDY OF MICHIGAN'S GREAT LAKES COMMERCIAL FISHERY By Z u l k i f l i H usin A DISSERTATION S u b m itte d t o M ich ig an S t a t e U n iv e r s it y i n p a r t i a l f u l f i l l m e n t o f t h e r e q u ir e m e n ts f o r th e d e g re e o f DOCTOR OF PHILOSOPHY D ep artm en t o f R eso u rce D evelopm ent 1984 © 1985 ZULKIFLI HUSIN All R ights Reserved ABSTRACT DEMAND, SUPPLY AND BIOECONOMIC ANALYSIS OF A REPLENISHABLE RESOURCE: A STUDY OF MICHIGAN'S GREAT LAKES COMMERCIAL FISHERY By Z u l k i f l i H u sin T h is s tu d y p ro v id e s e c o n o m ic v a l u e s f o r s e v e r a l G r e a t L a k e s com m ercial f i s h s p e c i e s ( w h i t e f i s h , c h u b , p e r c h , c a t f i s h , and a le w if e ) and e v a l u a t e s t h e i r p r i c e and p r o d u c tio n r e l a t i o n s h i p s . B ioeconom ic m o d e lin g and l i n e a r i z e d s u r p l u s p r o d u c t i o n e q u a t i o n s w e r e u s e d t o e s t i m a t e maximum s u s t a i n a b l e y i e l d eco n o m ic y i e l d a le w ife . (MSY) a n d maximum (MEY) f o r w h i t e f i s h a n d MSY f o r p e r c h , c a tfis h , and The e s t i m a t e d MEY o f w h i t e f i s h u s in g d i f f e r e n t tim e p e r io d s v a r i e d from a b o u t 2 .7 m i l l i o n pounds t o 8 . 4 m i l l i o n p o u n d s . P ro d u c e r s u r p l u s f o r w h i t e f i s h v a r i e d fro m $ 1 .6 m i l l i o n t o $9*2 m i l l i o n . T h is s tu d y i n d i c a t e s t h a t w h i t e f i s h s t o c k s may b e o v e r e x p l o i t e d , a l t h o u g h t h i s c a n n o t b e f i r m l y c o n c lu d e d . The MSY o f p e rc h was e s ti m a t e d t o b e 1 .2 2 m i l l i o n p o u n d s, c a t f i s h was 1 .0 m i l l i o n pounds and a l e w i f e w as 5 .8 7 m i l l i o n p o u n d s. The e s tim a te d e l a s t i c i t i e s f o r s e v e r a l f i s h s p e c i e s w e re : 1. W h ite fis h p r ic e e l a s t i c i t y - 2 . 8 9 ; in c o m e e l a s t i c i t y c ro ss p ric e o f dem and w as b e tw e e n - 2 . 4 and o f dem and b e tw e e n 0 .8 9 a n d 1 . 4 ; e l a s t i c i t y w ith b e e f a b o u t 0 .3 2 ; and c r o s s p r i c e e l a s t i c i t y w ith sh rim p b etw ee n 0 .1 3 and 0 .4 . P r i c e e l a s t i c i t y o f s u p p ly was b etw ee n 0 .2 and 0 .3 ; and c r o s s elasticity of supply with the price of trout was about -0.98. Price flexibility of supply was between 3.23 and 5.0. Chub p r i c e e la s tic ity o f demand was b etw ee n - 0 .5 1 and - 0 . 9 ; c r o s s p r i c e e l a s t i c i t y w ith b e e f w as b e tw e e n 1 .4 8 an d 1 . 6 ; and c r o s s e l a s t i c i t y w i t h c a n n e d f i s h w as b etw ee n 1 .3 4 and 2 .4 2 . P ric e e l a s t i c i t y o f s u p p l y w as b e tw e e n 0 .2 3 and 0 .8 5 ; and c ro ss e l a s t ic i ty o f s u p p ly w ith th e b e tw e e n - 0 . 7 4 an d - 1 . 2 4 . p ric e of p e r c h w as P r i c e f l e x i b i l i t y o f s u p p ly was b etw een 1 .1 8 and 4 .3 4 . P e r c h p r i c e e l a s t i c i t y o f demand was b etw ee n - 0 .8 0 and - 2 .5 1 ; and c r o s s p r i c e e l a s t i c i t y o f demand w ith sh rim p w as b e tw e e n 0 .1 8 and 0 .3 6 . C a tfis h p r ic e e l a s t i c i t y o f dem and w as a b o u t - 1 .9 5 ; c r o s s p r i c e e l a s t i c i t y w i t h b e e f w as b e tw e e n 0 .2 1 and 0 .2 9 ; and c r o s s p r i c e e l a s t i c i t y w ith f i s h s t e a k s was b etw ee n 0 .2 1 and 0 .2 4 . A le w if e p r i c e e l a s t i c i t y o f dem and w as b e tw e e n - 0 . 2 4 and - 0 . 2 8 ; in o o m e e l a s t i c i t y o f dem and a b o u t 1 0 . 8 ; a n d c r o s s p rio e e l a s t i c i t y s ig n s in d ic a te d w ith b e e f betw een - 2 . 0 and - 2 .7 * N e g a tiv e t h a t b e e f w as a c o m p le m e n ta r y g o o d w i t h a le w if e r a t h e r th a n a s u b s t i t u t e go o d . Price elasticity of demand was between 1.66 and 4.0, and the price flexibility of supply was between 0.25 and 0.60. 6. T he e s t i m a t e d s o c i a l s u r p l u s ( n e t a l l - o r - n o n e v a l u e ) was a b o u t $ 2 .4 m i l l i o n f o r w h i t e f i s h , $ 3 .6 m i l l i o n f o r c h u b s , $ 0 .8 m i l l i o n f o r p e r c h , and $ 0 .2 m i l l i o n f o r a l e w i f e . T h e s e e s t i m a t e s r a n g e d w id e l y o v e r t h e d i f f e r e n t tim e p e r i o d s exam in ed . Among s e v e r a l e c o n o m e trio m o d els u sed i n e s t i m a t i n g t h e demand and s u p p ly o f s e l e c t e d c o m m e r c ia l f i s h e r y s p e c i e s i n M ic h i g a n , o n l y t h e s i n g l e e q u a t i o n a n d a s y ste m o f two e q u a t io n s u s in g 2SLS and 3SLS gave th e b e s t e s t i m a t e s . O th e r m ethods y ie ld e d u n s a t i s f a c t o r y r e s u l t s . T h is s tu d y was l i m i t e d by th e m o d e l's i n a b i l i t y t o i n c o r p o r a t e much o f th e n e c e s s a r y in f o r m a tio n e i t h e r .b e c a u se th e d a t a w ere u n a v a i l a b l e o r w ere a v a i l a b l e b u t i n a c c u r a t e . T h e r e f o r e , th e m odel I t s e l f may n o t b e s t r e p r e s e n t th e s i t u a t i o n o f th e M ic h ig a n 's c o m m e r c ia l f i s h e r y . A m ore s u i t a b l e m odel m ig h t be r e q u ir e d and a t th e same tim e m ore c o m p le te and a c c u r a t e d a t a a r e a l s o n eed e d t o Im prove t h e e s t i m a t e s f o r M i c h i g a n 's G re a t L akes com m ercial f i s h e r y . D e d i c a t e d t o my f a t h e r and f a t h e r in - l a w who b o th p a s s e d away w h i l e I was p u r s u in g my s t u d i e s . ii ACKNOWLEDGMENTS Thanks t o th e A lm ig h ty God, " A l l a h , " w i t h o u t w h o se b l e s s i n g t h i s s tu d y w ould n o t have b e e n p o s s i b l e . T hen, I w is h to e x p re ss my a p p r e c i a t i o n go v ern m en t f o r p r o v i d i n g me w i t h a s c h o l a r s h i p to th e I n d o n e s ia n t h r o u g h MUCIA-AID t o s u p p o r t my g r a d u a te s t u d i e s a t M ich ig an S t a t e U n i v e r s i t y . My g r a t i t u d e a n d t h a n k s g o t o D r . D a n i e l R. T a lh e lm (R e so u rc e E c o n o m is t), c h airm an o f ny g u id a n c e co m m itte e and my t h e s i s a d v i s o r , who has sp e n t a g r e a t d e a l o f h is tim e g u i d i n g t h i s s tu d y . He g a v e me i n s i g h t t o a new f i e l d , f i s h e r y eco n o m ics. I a l s o w ish t o e x p r e s s my g r a t i t u d e t o D r. M i l t o n H. S t e i n m u e l l e r ( R e s o u r c e E c o n o m is t) o f ny g u id a n c e co m m itte e and my a d v i s o r who n e v e r s a i d " n o " a n y ti m e I w a n te d t o d u r i n g my g r a d u a t e s t u d i e s . d i s c u s s a n y a c a d e m ic p r o b le m s I h a d H is u n d e r s ta n d in g o f s t u d e n t s ' p ro b le m s , and h i s c o n t i n u o u s s u p p o r t f o r my p r o g r e s s c a n n e v e r b e a d e q u a t e l y th a n k e d . I a l s o w is h t o t h a n k t h e o t h e r members o f ny T h e s is and G uidance C om m ittee, D r. D a n ie l E. C h a p p e lle (R e so u rc e E co n o m ist) and D r. A n th o n y C. K oo ( E c o n o m i s t ) f o r t h e i r g u id a n c e , c o n s t r u c t i v e co m m en ts a n d s u g g e s tio n s w hich h av e s u b s t a n t i a l l y im p ro v ed t h i s s tu d y . I a l s o g r e a t l y b e n e f i t e d from d i s c u s s i o n s and i n f o r m a tio n s u p p lie d by D r. D o u g las J e s t e r , F is h e r y D iv is io n , M ich ig an D ep artm en t o f N a t u r a l R e s o u rc e s . To h im , I e x p r e s s my s i n c e r e th a n k s . iii My t h a n k s a l s o g o e s t o D r. A b d u lla h A l l , R e c to r o f U n iv e r s it y o f S y ia h K u a la , D r. I r a h im H asan, fo rm e r R e c to r , U n iv e r s it y o f S y ia h K u a la , and D r. S y a m s u d d l n M ahm ud, f o r m e r D ean o f F a c u l t y o f E o o n o m ic s , U n iv e r s it y o f S y ia h K u ala f o r g i v i n g me a l e a v e o f a b s e n c e t o g r a d u a t e s t u d i e s a t M ich ig an S t a t e U n i v e r s i t y . p u rsu e I n a d d i t i o n , I th a n k ay c o l l e a g u e s a t t h e F a o u l t y o f E c o n o m ic s f o r a l l th e ir su p p o rt and e n c o u ra g e m e n t. I a c k n o w le d g e w i t h many th a n k s The F o rd F o u n d a tio n i n J a k a r t a f o r p r o v id in g s u p p o r t f o r my fa m ily t o j o i n me i n t h e U n ite d S t a t e s ; and to T he A s ia n F o u n d a t i o n w h ic h g a v e me t h e o p p o r tu n i ty t o g e t a d d i t i o n a l t r a i n i n g a t th e en d o f my s tu d y , and made me f e e l b e t t e r p r e p a r e d b e f o r e g o in g b ack t o I n d o n e s ia . I am i n d e b t e d t o D r . J e a n T a y l o r an d C h r i s t i n e L o t t (MUCIA-AID o f f i c e i n M a d iso n ), and P am ela and J e f f P e t e r s , fo r a l l th e ir su p p o rt a n d e n c o u r a g e m e n t th r o u g h o u t my s t u d i e s ; t o S c o t t J o r d a n f o r a s s i s t i n g w ith th e co m p u ter program m ing; t o H e id i G r e th e r f o r h e r h e l p i n e d i t i n g th e d r a f t ; a n d t o N o ra B e c k e tt f o r p a i n s t a k i n g l y ty p i n g s e v e r a l d r a f t s o f t h e m a n u s c r ip t b e f o r e ty p in g t h i s f i n a l co p y . I w is h t o th a n k my m o th e r, who i n s p i t e o f h e r so rro w o f l o s i n g my f a t h e r , a lw ay s p ra y e d f o r my s u c c e s s and p a t i e n t l y w a ite d f o r my r e t u r n home. W ith o u t s u p p o r t o f my f a m i l y , who h a v e s h a r e d t h e h a r d s h ip s o f s t u d e n t l i f e w ith me f o r many y e a r s , t h i s w ork w ould p ro b a b ly n e v e r have b een c o m p le te d . F o r t h i s , I th a n k my w ife E l ly z a , ay d a u g h te r s I n d r y , F i t a , Y u li, and my young so n Amer, who alw ay s f a i l e d t o u n d e r s ta n d why I was n e v e r home. iv TABLE OF CONTENTS Page L i s t o f T a b le s ........................................................................................................................ L i s t o f F i g u r e s ................................................................. ............................................... . . . v ii x CHAPTER I 1 INTRODUCTION................................................................................................... . .................. P ro b lem s and I s s u e s f o r F is h e r y R e s o u rc e ................. 1 W orld Demand f o r and S u p p ly o f F is h e r y R e s o u r c e . . . . ................... 4 An O verview o f th e F i s h e r y S i t u a t i o n i n th e G re a t L a k e s .. . . . . . 9 10 O v e r f is h in g ................................................................. The I n v a s io n o f S e a L am p rey . ............................................................ 11 .................. .1 2 D e g r a d a tio n o f E n v iro n m e n t P ro b lem s o f M ich ig an G re a t L ak es ( G .L .) Com m ercial F i s h e r y . . . . 13 The P roblem S ta te m e n t.............................. 16 The O b je c tiv e s o f t h e S tu d y ....................................... 17 F is h S p e c ie s t o b e S tu d ie d .................................................................................. 18 O r g a n iz a tio n o f th e S tu d y ..... 19 CHAPTER I I REVIEW OF LITERATURE.......................................................................................................... CHAPTER I I I METHODS OF THE STUDT.......................................................................................................... The B io eco n o m ic M odel............................................................................ L i n e a r iz e d S u r p lu s P r o d u c tio n M e th o d . .................................................. Demand and S u p p ly M odel......................................................................................... S in g le - E q u a tio n M ethod.......................................................................... S im u lta n e o u s - E q u a tio n M ethod.............................................................. ....................................................... I d e n t i f i c a t i o n o f t h e E q u a tio n R educed F o r m . . . ................................................................................... I n d i r e c t L e a s t S q u a re ( I L S ) . . . . . . ............................................................... Two S ta g e L e a s t S q u a re (2SLS) and T h re e -S ta g e L e a s t S q u a re (3SLS) w ith Two and F o u r E q u a tio n s .................................. D a ta and I n f o r m a tio n Used i n t h i s S tu d y .................................... M ethod o f C a l c u l a t i n g C PI..................................................................................... CHAPTER IV DESCRIPTION AND ANALYSIS OF MICHIGAN'S GREAT LAKES COMMERCIAL FISHERY........................................................................................................................................ W h ite f is h (C o reg o n u s c l u p e a f o r m i s ) ............................................................... Chubs (C o reg o n u s h o y i ) ......................... Y ellow P e rc h (P e ro a f l a v e s c e n s ) ..................................................... C a t f i s h ( I c t a l u r u s p u n c t a t u s ) ........................................................... A lew iv es (A lo sa p s e u d o h a r e n g u s ) ......................................... v 22 44 44 50 52 52 53 54 55 56 57 58 59 62 62 70 77 81 88 CHAPTER V ESTIMATION OF BIOECONOMIC MODEL PARAMETERS.................................................. E s tim a te o f B ioeoonom ic A n a ly s is U sin g L i n e a r i z a t i o n S u r p lu s P r o d u c tio n T e c h n iq u e ................................................... 99 114 CHAPTER VI ESTIMATION OF DEMAND AND SUPPLY PARAMETERS.................................................. I n t r o d u c t i o n ............................................................ E s tim a tio n P r o c e d u r e ......................... E s tim a te s U sin g th e S in g le E q u a tio n M ethod ...................... Demand E s ti m a t io n s ................ W h i t e f i s h ................................................................................................................ C hubs................................... P e ro h ...................................................................................... C a t f i s h ..................................................................................................................... A le w ife ............................................................................................................. S u p p ly E s ti m a t io n s ............................................................................... W h i te f is h ................................................................................................................ C hubs............................ P e r c h .......................................................................................................................... C a t f i s h ..................................................................................................................... A le w ife ........................................................................................................ E s tim a te s U sin g S im u lta n e o u s E q u a tio n s M e t h o d . . . . . . . . . . . . . . . . . R educed Form................ I n d i r e c t L e a s t S q u a r e s . ....................................... Two and T h ree S ta g e L e a s t S q u a re s (2SLS and 3 S L S ) . . . . ............... E l a s t i c i t i e s and F l e x i b i l i t i e s . . . . . . . .............................................. S o c i a l S u r p lu s (N et a l l - o r - n o n e V a lu e ) o f S e v e r a l F is h S p e c ie s from M ich ig an C om m ercial F i s h e r i e s ........... W h i te f is h ................................................................................................................. C hubs........................................................................................ P e r c h ............................................ A le w ife ............................................................................................. 152 154 156 158 158 CHAPTER V II SUMMARY, CONCLUSION AND RECOMM3NDATION........................................................... .S u m m a ry ............................................................................................. C o n c lu s io n s and R e c o m m e n d a tio n s................................ S u g g e s tio n s f o r F u r t h e r R e s e a rc h .................................. 163 163 168 170 BIBLIOGRAPHY............................................................................................................................ G e n e ra l R e f e r e n c e s .................. 172 178 vi 120 120 124 132 133 133 135 135 136 136 137 137 139 139 140 140 140 141 143 144 149 LIST OF TABLES Table Page 1-1 W orld P r o d u c tio n o f L iv in g A q u a tic O rganism .............. .................. 5 1 -2 E s tim a te d Demand f o r F i s h 1980, 1990, 2000..................................... 7 1 -3 A q u a tio O rganism — A c tu a l and E s tim a te d P r o d u c t i o n . . . . . . . 8 I-4 The V alue o f th e U .S . and C an ad ian Com m ercial F is h in g C atch from t h e G r e a t L akes 1975 - 1982 ( i n M i l l i o n ) ...... II-1 The A p p lic a tio n o f S c h a e f e r M odel................... IV - 1 W h ite f is h P r o d u c tio n fro m M ich ig an G r e a t L ak es and I t s R e l a ti o n s h i p t o U .S . an d th e Whole G re a t L ak es P r o d u c tio n 1 9 6 0 -1 9 8 2 ............................................................................... IV -2 IV -3 IV -4 15 33 63 A verage P e r c e n ta g e o f M ich ig an P r o d u c tio n O ver U .S . and th e Whole G r e a t L akes P r o d u c tio n f o r S e v e r a l F is h S p e c ie s 1 9 6 0 -1 9 8 2 .......................................... 64 A nnual C u r r e n t and R eal L an d in g P r i c e s o f Lake W h i te f is h , Chub, Lake T r o u t , Y ellow P e r c h , C a t f i s h and A le w ife p e r pound i n M ich ig an 1960-1982 (19 8 2 i s b a s e y e a r ) .................. 66 C atch and E f f o r t f o r D i f f e r e n t Types o f G e a r, and C ato h p e r U n it o f E f f o r t (CPE) f o r S ta n d a rd G ear f o r Lake W h ite f is h i n M ich ig an G r e a t L ak es W ater 1 9 6 0 -1 9 8 2 ................................... 71 IV -5 Chub P r o d u c tio n fro m M ich ig an G r e a t L ak es and I t s R e l a ti o n s h i p t o U .S . and t h e Whole G re a t L ak es P r o d u c tio n 1 9 6 0 -1 9 8 2........................................................................................................ 73 IV -6 C atoh and E f f o r t f o r D i f f e r e n t T ypes o f G e a r, and C ato h p e r U n it o f E f f o r t (CPE) f o r S ta n d a rd G ear f o r Chubs i n M ich ig an G re a t L ak es W ater 1 9 6 0 -1 9 8 2 ......................................... 78 IV -7 Y ellow P e rc h P r o d u c tio n fro m M ich ig an G re a t L ak es and I t s R e l a ti o n s h i p t o U .S . an d th e Whole G re a t L ak es P r o d u c tio n 1 9 6 0 -1 9 8 2........................................................................................................ 79 IV -8 C atch and E f f o r t f o r D i f f e r e n t T ypes o f G e a r, and C a tc h p e r U n it o f E f f o r t (CPE) f o r S ta n d a rd G ear f o r Y ellow P erch i n M ich ig an G r e a t L ak es W ater 1 9 6 0 -1 9 8 2 ............................ vii 84 IV -9 C a t f i s h P r o d u c tio n fro m M ich ig an G re a t Lakes and I t s R e l a ti o n s h i p t o U .S . and th e Whole G re a t L akes P r o d u c tio n 1960-1982 IT -1 0 IV -11 I T - 12 IT -1 3 IT -1 4 T-1 T -2 T -3 T -4 T-5 T-6 T -7 T -8 86 C atch and E f f o r t f o r D i f f e r e n t T ypes o f G e a rf and C a tc h p e r U n it o f E f f o r t (CPE) f o r S ta n d a rd G ear f o r C a t f i s h on M ich ig an G re a t L ak e s W ater 1960 -1 9 8 2 .............................. 90 A le w ife P r o d u c tio n from M ich ig an G re a t L akes and I t s S h a re o f U .S . P r o d u c tio n 1960-1982 ...................................................... 92 C ato h and E f f o r t f o r D i f f e r e n t Types o f G ear, and C atch p e r U n it o f E f f o r t (CPE) f o r S ta n d a rd G ear f o r A le w iv e s i n M ich ig an G r e a t L akes W ater 1 9 6 0 -1 9 8 2 ........................................... 96 A nnual G rowth R a te o f P r o d u o tio n , C u r r e n t P r i c e s , and R eal P r i c e s o f S e v e r a l M ich ig an Com m ercial F is h S p e c ie s 1 9 6 0 -1 9 8 2................................................................................................................. 97 A nnual U .S . C u r r e n t and R eal ( p e r p ound) P r i c e s o f S e v e r a l Com m ercial F is h S p e c ie s fro m U .S . G re a t L akes W a te rs (1 9 6 0 -1 9 8 2 )..................... 98 T o t a l C a tc h , C ato h p e r U n it o f E f f o r t , and T o t a l E f f o r t o f W h ite f is h fro m M ic h ig a n 's G r e a t L akes W aters 1960-1982 (U sin g L a rg e Mesh T ra p N e ts and G i l l n e t s a s S ta n d a rd G e a r ) ...................................................................................................... 100 T o t a l C a tc h , C ato h p e r U n it o f E f f o r t , and T o ta l E f f o r t o f Chubs fro m M ic h ig a n 's G re a t L akes W aters 1960-1982 (U sin g 2 I n c h G i l l n e t s a s S ta n d a rd G e a r ) .................... 101 T o ta l C a tc h , C a tc h p e r U n it o f E f f o r t , and T o ta l E f f o r t o f Y ellow P e rc h from M ic h ig a n 's G re a t L akes W a te rs 1960-1982 (U s in g S m a ll Mesh T rap N e ts a s S ta n d a rd G e a r ) . . . 102 T o t a l C a to h , C ato h p e r U n it o f E f f o r t , and T o t a l E f f o r t o f C a t f is h from M ic h ig a n 's G re a t L akes W aters 1960-1982 (U sin g S m a ll Mesh T ra p N e ts a s S ta n d a rd G e a r ) ............................. 103 T o ta l C a tc h , C a tc h p e r U n it o f E f f o r t , and T o ta l E f f o r t o f A lew iv es fro m M ic h ig a n 's G re a t L ak es W aters 1960-1982 (U sin g Pound N e ts a s S ta n d a rd G e a r ) .................................................... 104 E s tim a te s o f th e P a r a m e te r s , k , K, and q fo ^ th e L o g i s t i c S u r p lu s P r o d u c tio n M odel.............................................................................. 106 E s tim a tio n o f B io eco n o m ic T a lu e s f o r W h ite f is h (U sin g 1960-1982 d a t a ) ................................................................................................... 115 E s tim a tio n o f t h e B ioeconom ic T a lu e s f o r W h ite f is h (U sin g 1971-1982 d a t a ) .................................................................................. 115 viii V I-9 V I-1 V I-2 V I-3 V I-4 V I-5 V I-6 V I-7 V I-8 V I-9 V I-1 0 V I-11 V I-1 2 V II-1 E s tim a tio n o f th e B ioeconom ic V a lu e s f o r W h ite f is h B ased on 1973 D a ta ............................................................... 116 C o r r e l a t i o n C o e f f i c i e n t s Among t h e V a r ia b l e s Used i n th e E s tim a tio n o f Demand and S u p p ly F u n c tio n s o f W h i t e f i s h . . . . 126 C o r r e l a t i o n C o e f f i c i e n t Among t h e V a r ia b l e s Used i n th e E s tim a tio n o f Demand and S u p p ly F u n c tio n s o f C hubs................. 127 C o r r e l a t i o n C o e f f i c i e n t s Among th e V a r ia b l e s Used i n th e E s tim a tio n o f Demand and S u p p ly F u n o tio n s o f Y ellow P e rc h ..................... 128 C o r r e l a t i o n C o e f f i c i e n t s Among th e V a r ia b le s Used i n t h e E s tim a tio n o f Demand and S u p p ly F u n c tio n s o f C a t f i s h 129 The E s tim a te d Demand F u n c tio n s f o r S e v e r a l F is h S p e c ie s on M ichigan G re a t L akes C om m ercial F is h e r y w ith O rd in a ry L e a s t S q u a r e s ................................ 134 The E s tim a te d S u p p ly F u n c tio n s f o r S e v e r a l F is h S p e c ie s on M ich ig an G re a t L ak es Com m ercial F is h e r y w ith O rd in a ry L e a s t S q u a r e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 The E s tim a te d Demand and S u p p ly F u n c tio n s f o r S e v e r a l F is h S p e c ie s U sin g t h e R educed Form M e t h o d ................................ 142 The E s tim a te d Demand and S u p p ly F u n o tio n s f o r S e v e r a l F is h S p e c ie s U sin g Two and T h re e S ta g e L e a s t S q u a re s (2SLS and 3SLS) M ethod (W ith J u s t - I d e n t i f i e d C a s e ) ................ 145 The E s tim a te d Demand and S u p p ly F u n o tio n s f o r S e v e r a l F is h S p e c ie s U sin g Two and T h re e S ta g e L e a s t S q u a re s (2SLS and 3SLS) M ethod (W ith O v e r - I d e n t i f i e d C a s e ) ................ 147 The E s tim a te d Demand and S u p p ly F u n o tio n s f o r S e v e r a l F is h S p e c ie s U sin g Two and T h re e S ta g e L e a s t S q u a re s (2SLS and 3SLS) Method (W ith F o u r E q u a tio n S y s te m s ) ................. 148 Demand and S u p p ly E l a s t i c i t i e s f o r S e v e r a l F is h S p e o le s from M ic h ig a n 's G re a t L a k e s ................................................................... 151 Demand and S u p p ly E l a s t i c i t i e s f o r S e v e r a l F is h S p e o ie s from M ich ig an G re a t L akes ( E s tim a te d by 2SLS and 3SLS M eth o d s)................................................................................................................... 153 The E s tim a te s o f S o c ia l S u r p lu s ( n e t a l l - o r - n o n e v a lu e ) f o r S e v e r a l Com m ercial F is h S p e o ie s i n M ich ig an ( i n th o u sa n d d o l l a r s ) .............................................................................................. 167 ix LIST OF FIGURES Figure Page 1-1 The W orld C atch o f M arine F is h e s fro m 1 9 5 0 -1 9 7 6 ............ I-2 G re a t L ak es F i s h e r y ...................... 20 II-1 B io l o g ic a l M odel.................................................. 26 II-2 Econom ic Model ( S t a t i c ) . ........................................................................... 26 II-3 G o rd o n 's Optimum L e v e l o f U t i l i z a t i o n o f F is h in g R e s o u r c e .. 29 II-4 The B i o l o g i c a l o f F is h P o p u la tio n and R esponse t o th e H a rv e s t Over Time B ased o n L o g i s t i c M odel. . . . . . . . . . . . . . . . . . 30 II-5 S u r p lu s f i e l d M odel............................................................................................. 31 II-6 The S im p le S c h a e f e r 's Model A. The L o g i s t i c Curve o f P o p u la tio n Growth B. The Y ie ld -B io m a ss and T i e l d - E f f o r t R e l a t i o n s h i p ................. 34 II-7 L o n g -ru n F is h e r y S u p p ly and Demand C u r v e s . . . .................................. 37 IV -1 A nnual M ich ig an Lake W h ite f is h L a n d in g s , A nnual C u r r e n t P r i c e and A nnual R eal P r i c e s 1 9 6 0 - 1 9 8 2 . . . . . . . . . . ........................ 67 R eal P r ic e and Q u a n tity o f W h ite f is h L an d in g s i n M ich ig an , 1960-1982 ................................................................................................................... 68 A nnual M ich ig an Chub L a n d in g s , A nnual C u rre n t P r i c e , and A nnual R e a l P r lo e 1960-1982 ( i n 1982 d o l l a r s ) ............................... 75 R eal P r ic e and Q u a n tity o f Chub L an d in g s i n M ich ig an , 1 9 6 0 -1 9 8 2................................................................................................................... 76 A nnual M ich ig an P e rc h L a n d in g s , A nnual C u r r e n t P r i c e , and A nnual R eal P r l o e 1 9 6 0 - 1 9 8 2 . . . . . . . . . . . . . . . ........................... 82 R eal P r ic e and Q u a n tity o f Y ellow P e rc h L an d in g s i n M ich ig an 1960 -1 9 8 2.............................................................................................. 83 A nnual M ich ig an C a t f is h L a n d in g s , A nnual C u rre n t P r i c e , and A nnual R eal P r ic e 196 0 -1 9 8 2............................................ 87 IV -2 IV -3 IV -4 IV -5 IV -6 IV -7 x 5 IV -8 IV -9 I V - 10 V-1 V-2 R eal P r ic e and Q u a n tity o f C a t f is h L an d in g s I n M ich ig an 1 9 6 0 -1 9 8 2 ................................................................................................................... A nnual M ich ig an A le w ife L a n d in g s , A nnual C u r r e n t P r i c e , and A nnual R e a l P r lo e 1 9 60-1982................. 94 R eal P r ic e and Q u a n tity o f A lew ife L an d in g s I n M ich ig an , 1960-1982 ................................................................................................................... 95 E s tim a te d E q u ilib r iu m C atoh ( y i e l d ) and E f f o r t R e l a ti o n o f W h ite f is h U sin g L i n e a r iz e d S u r p lu s P r o d u c tio n T ec h n iq u e (196 0-1982 ) ....................................................................................... 109 E s tim a te d E q u ilib r iu m C atch ( Y ie ld ) and E f f o r t R e l a ti o n o f W h ite f is h U sin g L in e a r iz e d S u r p lu s P r o d u c tio n T ec h n iq u e ( 1971- 1982) V-3 V-4 V-5 V I-1 V I-2 V I-3 V I-4 89 110 E s tim a te d E q u ilib r iu m C atch ( Y ie ld ) and E f f o r t R e l a ti o n o f P e rc h U sin g L i n e a r iz e d S u r p lu s P r o d u c tio n T ec h n iq u e (1 9 6 0 -1 9 8 2 ).............................................................................................................. 111 E s tim a te d E q u ilib r iu m C atoh ( y i e l d ) and E f f o r t R e l a ti o n o f C a t f i s h U sin g L i n e a r iz e d S u r p lu s P r o d u c tio n T ec h n iq u e (1 9 6 0 -1 9 8 2 ).............................................................................................................. 112 E s tim a te d E q u ilib r iu m C atoh ( Y ie ld ) and E f f o r t R e l a ti o n o f A le w ife u s in g L in e a r iz e d S u r p lu s P r o d u c tio n T ec h n iq u e ( 1 9 7 1 -1 9 8 2 ).............................................................................................................. 113 E s tim a te d Demand and S u p p ly C u rv e s, S o c ia l S u r p lu s o f W h ite f is h from M ich ig an G re a t L ak es W a te rs ....................... 155 E s tim a te d Demand and S u p p ly C u rv e s , S o c i a l S u r p lu s o f Chubs from M ich ig an G re a t L akes W a te rs .............................. 157 E s tim a te d Demand and S u p p ly C u rv e s, S o c ia l S u r p lu s o f P e rc h from M ich ig an G r e a t L akes W a te rs ............................................... 159 E s tim a te d Demand and S u p p ly C u rv e s, S o c ia l S u r p lu s o f A le w ife from M ich ig an G r e a t L ak es W a te rs ........................................... 161 xi CHAPTER I INTRODUCTION I n g e n e r a l , t h i s c h a p t e r w i l l d i s c u s s th e p ro b le m s and i s s u e s fa c e d by f i s h e r y r e s o u r c e s w o rld w id e , th e w o rld demand f o r and s u p p ly o f f i s h c o m m o d it ie s , a n d t h e i r p r o s p e c t s i n t h e f u t u r e . fis h e ry re so u rc e s c o m m e r c ia l f i s h e r y F in a lly , in th e T he s i t u a t i o n of G r e a t L a k e s a n d p r o b le m s f a c e d b y t h e i n d u s t r y i n M ic h ig a n w i l l b e r e v ie w e d b r i e f l y . t h e i m p o r t a n t , o b j e c t i v e s and o r g a n i z a t i o n o f t h i s s tu d y w i l l a l s o be p r e s e n te d i n t h i s c h a p t e r . P ro b lem s and I s s u e s f o r F is h e r y R eso u rce F is h e rie s , as a re p le n is h a b le re s o u rc e , h a v e n o t g o t t e n much a t t e n t i o n u n t i l t h e l a s t tw o d e c a d e s , e s p e c i a l l y r e g a r d i n g how t h i s r e s o u r c e w as e x p l o i t e d an d a l l o c a t e d t o s a t i s f y human n e e d . m a in ly due t o t h e b e l i e f t h a t a f i s h e r y i s th e re fo re , an in e x h a u s tib le re s o u rc e , e v e r y b o d y c a n h av e a c c e s s t o th e r e s o u r c e s to c k and e x p l o i t i t a s much a s p o s s i b l e . ra p id ly , T h is was fis h H owever, a s t h e w o r l d 's p o p u l a t i o n h a s g ro w n c o n s u m p tio n h a s g ro w n a s w e l l . I n r e s p o n s e t o g ro w in g demand, f is h e r m e n im p r o v e f i s h i n g t e c h n o l o g y t o e n a b l e th e m t o m o re in te n s iv e ly and e x te n s iv e ly h a rv e s t f i s h s to c k s . T h is i n f a c t h a s p u t more p r e s s u r e o n f i s h p o p u la tio n s and h a s f o r c e d t h e w o r ld p r o d u c t i o n le v e l to th e p o in t o f d im in is h in g r e t u r n s . C o n s e q u e n tly , th e s to c k s m ig h t n o t be a b le t o ren ew th e m s e lv e s t o t h e fo rm e r l e v e l o f h a r v e s t i n g . T h is o c c u r s b e c a u se th e num bers o f f i s h c a u g h t a t c e r t a i n p o i n t s i n tim e may e x c e e d t h e g r o w th o f t h e f i s h p o p u la tio n . The f i s h s to c k w ill t h e r e f o r e d e c r e a s e a n d t h e f u t u r e h a r v e s t w i l l p ro b a b ly d ro p a s w e l l . W ith o u t any e f f o r t t o c o n t r o l and r e g u l a t e t h e u s e o f f i s h e r y r e s o u r c e s ; t h e c o n t i n u a t i o n o f o v e r f i s h i n g c o u l d c o l l a p s e o v e r a l l p r o d u c tio n o f c e r ta in f i s h s p e c ie s . In re c e n t y e a rs, m o re a t t e n t i o n h a s b e e n g iv e n t o th e p ro b lem o f f i s h e r y r e s o u r c e u t i l i z a t i o n by i n t e r n a t i o n a l a g e n c i e s a n d by c o a s t a l s ta te s . Many e f f o r t s h a v e b e e n m ade t o p r e v e n t o v e r e x p l o i t a t i o n by c o n t r o l l i n g t h e l e v e l o f f i s h h a r v e s t i n g o r by o t h e r r e g u l a t i o n s . As a re n e w a b le b u t d e s t r u c t i b l e r e s o u r c e , f i s h e r i e s h av e a two f o l d c o n s e r v a tio n p ro b le m . w h ic h F is h s t o c k s may b e v ie w e d b o t h a s a n i n v e n t o r y s h o u ld be u t i l i z e d w is e ly and e c o n o m ic a lly , and a l s o a s th e c a p i t a l e q u ip m en t w h ich p r o v id e s f o r r e p le n is h m e n t o f t h e r e s o u r c e f o r f u t u r e u s e ( C r u t c h f i e l d and P o n te c o rv o , 1 9 6 8 ). re so u rc e s is s im ila r to M cln ern ey ( 1 9 8 1 ) : T h is c o n c e p t o f f i s h e r y tw o t y p e s o f c h a r a c t e r i s t i c s m e n t i o n e d by ( a ) u t i l i z a t i o n o f a u n i t o f t h e r e s o u r c e im p lie s i t s d e s tr u c tio n , a consequent d e p le tio n o f th e e x i s t i n g p h y s ic a l r e s o u r c e s t o c k an d t h e c o m p le te and i r r e v o c a b l e l o s s o f th o s e r e s o u r c e s e r v i c e s ; and (b ) th e s to c k o f r e s o u r c e s e r v i c e s c a n be augm ented a g a in t o e n a b l e a c o n t in u in g a v a i l a b i l i t y th ro u g h tim e . Due t o i t s b i o l o g i c a l n a t u r e , f i s h e x p l o i t a t i o n can be in c r e a s e d i n o r d e r t o g e t h i g h e r y i e l d w i t h o u t r e d u c i n g t h e s t o c k , a s lo n g a s th e r a t e o f e x p lo ita tio n i s n o t g r e a t e r th a n th e r a t e H o w e v er, w i t h o f b io m a s s g r o w t h . i n c r e a s e d e f f o r t , y i e l d can r e a c h a maximum, a f t e r w hich f u r th e r in c re a s e s in e f f o r t w ill r e s u lt c o n d itio n i s g e n e r a lly in a lo w e r y i e l d . c o n s id e re d o v e r e x p l o ita tio n . T h is As e f f o r t s a r e in c r e a s e d f u r t h e r , th e r a t e o f b io m a ss g ro w th o a n n o t k eep p a c e w i t h t h e 3 r a te o f e x p lo ita tio n , th e re fo re th e s to c k w i l l d e c re a s e f u r t h e r to lo w e r l e v e l , a n d m ay e v e n b e d e p l e t e d . e x p e rie n c e d i n th e p a s t, a T h is s c e n a r io h a s b e e n an d c o n c e i v a b l y c o u l d b e c o n t i n u e d i n t h e f u t u r e i n th e a b sen o e o f p r i v a t e o w n e rsh ip o r r e g u l a t i o n . As a common p r o p e r ty r e s o u r o e l e v e ry b o d y h a s a c c e s s t o e x p l o i t th e f i s h e r y r e s o u r c e an d u s u a l l y h a s a n o b j e o t i v e t o m a x im iz e c u r r e n t p ro fit. H o w e v e r, w ith f r e e c o m p e titio n u n d e r open a c c e s s th e l e v e l o f e x p l o i t a t i o n c o u ld r e a c h t h e r a n g e i n w h lo h no m ore p r o f i t c o u l d b e o b t a i n e d fro m t h e f i s h i n g e f f o r t . T h is r a n g e , from an econom ic v ie w , w ould be re g a rd e d a s a m is a llo c a tio n o f th e f a c t o r s o f p ro d u c tio n . U nder o p e n a c c e s s th e p r o d u c tio n o f f i s h w ould o c c u r a t th e p o i n t w here m a rg in a l c o s t o f e x t r a u n i t s o f f i s h i n g w o u ld e q u a l th e a v e r a g e r e v e n u e from t h a t u n i t ( B u t l i n , 1973)* T h is e x p l o i t a t i o n b e h a v io r i s n o t u n u s u a l f o r common p r o p e r t y r e s o u r c e s a s d e s c r ib e d by H a rd in (1 9 6 8 ) i n th e "T rag ed y o f The Commons" "A s a p a s t u r e o p e n t o a l l , i t i s e x p e c te d t h a t e a c h herd sm an w i l l t r y t o k e e p a s many o a t t l e a s p o s s i b l e o n t h e com m ons. ....A s a ra tio n a l b e in g ea c h h erdsm an s e e k s t o m axim ize h i s g a i n . th e r a t i o n a l herd sm an c o n o lu d e s t h a t th e o n ly s e n s i b l e c o u rs e f o r h im t o p u rs u e i s t o add a n o t h e r a n im a l t o h i s h e r d . And a n o t h e r , and a n o t h e r . B u t t h i s i s th e c o n c l u s i o n r e a c h e d by e a c h a n d e v e r y r a t i o n a l h erd sm a n s h a r in g a com m ons. T h e r e i n t h e t r a g e d y . E a c h m an i s l o o k e d i n t o a s y s t e m t h a t c o m p e l s h im t o i n c r e a s e h i s h e r d w i t h o u t l i m i t - i n a w o r ld th a t is lim ite d . R u in s i s t h e d e s t i n a t i o n to w a rd w hich a l l men r u s h , e a c h p u r s u in g h i s own b e s t i n t e r e s t i n a s o c i e t y t h a t b e l i e v e s i n th e freed o m o f t h e com m ons. F re e d o m i n a commons b r in g s r u i n t o a l l . " I C r u t c h f i e l d an d P o n te c o r v o ( 1 9 6 8 ) do n o t u s e t h e p r o p e r ty r e s o u r c e " i f th e r e s o u r c e i s n o t ow ned, o r i s n o t in th e case o f f is h e r ie s . T hey i n s t e a d u s e t h e te r m re s o u rc e ." H o w e v e r, i n t h i s s t u d y , I u s e b o th o f in d iffe re n tly . te rm "common p ro p e rty as "open a c c e s s th e s e te rm s M ore f i s h e r m a n w i l l e n t e r t h e f i s h e r y r e v e n u e s e x c e e d th e c o s t s . i n d u s t r y a s lo n g a s th e T h is p r o o e s s w i l l c o n t i n u e u n t i l a l l th e ir n e t p r o f i t s h av e b een c o m p le te ly d r a in e d aw ay, and t h e f i s h e r y r e s o u r c e i s a p p a r e n tly o v e r e x p l o i t e d . by w a te r p o l l u t i o n . u s e d a s w a s te dumps. c a p a c ity Many c o a s t a l o r in la n d w a te r r e s o u r c e s h a v e b een C o n ta m in a tio n w i l l r e d u c e t h e w a t e r ' s c a r r y i n g as a liv in g c o n ta m in a te d f i s h . T h is p ro b lem h a s b een a g g r a v a te d f u r t h e r e n v iro n m e n t f o r f i s h s p e o ie s a n d /o r p ro d u c e T feis c o n t a m i n a t i o n m ay, i n e f f e c t , r e d u o e th e q u a n t i t y a s w e l l a s t h e q u a l i t y o f f i s h h a r v e s te d , t h e r e f o r e , r e d u c in g t h e a v a i l a b i l i t y o f f i s h f o r human u s e . P o l l u t i o n t h e n c o m p e te s w i t h n a t u r a l m o r t a l i t y and f i s h i n g e f f o r t i n r e d u o in g f i s h e r y r e s o u r c e s . W orld Demand f o r and S u p p ly o f F is h e r y R eso u rce As w o rld p o p u la tio n grew and n u t r i t i o n b ecam e a c e n t r a l p r o b le m , m any c o u n t r i e s b eg an t o lo o k t o th e o c e a n a s one o f th e r e s o u r c e s w hich c o u ld h e l p t o s o lv e t h i s p ro b lem . D i f f e r e n t m o d e ls a n d t e c h n i q u e s h a v e b e e n u s e d b y s c h o l a r s t o e s ti m a t e t h e fo o d p o t e n t i a l fro m o c e a n s . 100 m i l l i o n t o 2 b i l l i o n The e s t i m a t e s v a ry fro m u n d e r to n s o f a n n u a l p ro d u o tio n . A fo u r-b illio n w o rld p o p u la tio n w ould r e q u i r e 60 m i l l i o n m e tr io to n s o f f i s h t o p r o v id e 30 p e r c e n t o f t h e 36 g ram s o f p r o t e i n n eeded d a l l y p e r p e r s o n . By th e y e a r 2 0 0 0 , 100 m i l l i o n t o n s o f f i s h w ould be r e q u i r e d j u s t t o m a i n t a i n t h e same l e v e l o f p r o t e i n . O v er t h e l a s t d e c a d e , ho w ev er, th e t o t a l f i s h h a r v e s t seem s t o be l e v e l i n g o f f d e s p i t e in c r e a s e d f i s h i n g e f f o r t ( F ig u r e 1 - 1 ) . 5 Millions of Tons 100 5 0 .. 1952 1960 Years 1970 1976 Source: Hennemu th,19 7 9 . Figure 1 - 1 . T he r a t e The World Catch o f Marine Fishes from 1 9 5 0 - 1 9 7 6 o f g ro w th o f w o r ld f i s h p r o d u c tio n h ad d e c l in e d s h a r p ly from about 6 p e rc e n t in th e 1 9 6 0 's t o l e s s th a n 1 p e rc e n t in th e 1 9 7 0 's (T a b le 1 - 1 ) . T a b le 1 - 1 . W orld P ro d u c tio n o f L iv in g A q u a tic O rganism P ro d u c tio n ( m i l l to n s ) In crease (m ill to n s ) R a te o f in c re a s e (%/year) 1960 1970 1977 T o ta l W orld 4 0 .2 7 0 .7 7 3 .5 3 0 .5 2 .8 5 .8 0 .5 D ev elo p in g C o u n tr ie s 1 7 .0 36.1 3 4 .2 19.1 - 1 .9 7 .8 - 0 .6 D eveloped C o u n tr ie s 23-2 3 4 .6 3 9 .3 11 .4 4 .7 4 .1 S o u rc e : R o b in so n , 1980. 1 9 70/60 1977/70 1 9 70/60 1977/70 1 .8 6 T he b a s i c cause o f t h i s d e c lin e a p p e a rs to be th e d im in is h in g s to o k s o f t h o s e c o n v e n t i o n a l f i s h w h io h o f f e r t h e p o s s i b i l i t y s u s ta in e d in o re a s e in o a to h . now y i e l d much lo w e r o a t c h e s . o f fis h in g of a Some s p e o i e s ' s to c k s h a v e c o l l a p s e d and U n le s s o a r e f u l management and r e g u l a t i o n e f f o r t s f o r t h o s e s p e c i e s a r e im p o s e d , c a t c h e s may n o t I n c r e a s e t o fo rm e r l e v e l s ( B o b in s o n , 1 9 8 0 ). R o b in s o n a l s o e s t i m a t e s t h a t c o n su m p tio n o f a q u a t i c o rg a n is m s w i l l i n c r e a s e a t a b o u t 3 -3 p e r c e n t p e r y e a r by th e en d o f t h i s c e n tu r y w h ile th e p r o d u c t i o n w i l l i n c r e a s e ab o u t 1 p e r c e n t p e r y e a r ( s e e T a b le 1 -2 and 1 - 3 ) . T h e r e f o r e , th e g ro w th i n p r o d u c tio n w i l l be in a d e q u a te , on t h e a v e r a g e , t o m a i n t a i n c u r r e n t p e r c a p i t a c o n su m p tio n l e v e l s . D a ta fro m T a b l e 1 - 3 a l s o i n d i c a t e s t h a t t h e r a t e o f p r o d u c tio n gro w th i s r e l a t i v e l y m ore f a v o r a b l e i n d e v e lo p in g c o u n t r i e s . T h ey w i l l c o n t r i b u t e 75 p e r c e n t o f t h e t o t a l in o r e a s e by th e y e a r 2 0 0 0 . due t o t h e f a c t t h a t l e s s e x p l o i t e d r e s o u r c e s i n d e v e l o p i n g T h is i s c o u n trie s h a v e l e f t m ore f i s h th a n i n th e d e v e lo p e d c o u n t r i e s w h ere te c h n o lo g ic a l in n o v a tio n h a s l e d t o t h e e a r l i e r e x p l o i t a t i o n o f s t o c k s . Im p ro v e d te c h n o lo g y i n th e f i s h e r y r e s o u r c e s i s m a in ly d i r e c t e d to w a rd h a r v e s t i n g r a t h e r th a n p ro d u c in g . I n e f f e c t t h i s may o v e r e x p l o i t f i s h e r y s to c k s f u r t h e r , a s i s h a p p e n in g i n many a r e a s . As a c o n s e q u e n c e , t h e s to c k s can be d e p l e te d and f i s h p r o d u c tio n r e d u c e d . A lo n g w i t h th e c u r r e n t s ta g n a n t t o t a l fis h h a rv e s t, a b o u t 35 p e r c e n t o f t h e f i s h i n g c a t c h o r n e a r l y 25 m i l l i o n to n s o f f i s h a r e l o s t a n n u a lly d u r in g th e p r o c e s s in g p ro c e d u re . T h is l o s s m a in ly o c c u rs i n th e d e v e lo p in g c o u n t r i e s w h ic h 'la o k t h e c a p i t a l , s k i l l s in h a n d lin g , p ro c e s s in g and m a rk e tin g o f fis h and te c h n o lo g y (P a ris e r, 1 9 7 9 ). T h e r e f o r e , r e d u c in g p o s t h a r v e s t l o s s e s i s e s s e n t i a l n o t o n ly t o r e d u c e Table 1-2. Estimated Demand for Fisb I960, 1990, 2000 (in live weight equivalent) Total (million tons) Consumption Projected demand 1972-7* 1980 Feed (million tons) Comsuptlon Projected demand 1980 1990a 2000a 1972-74 Vorld Developing Dating America Africa Near East Far East Aslan Centrally planned countries Other developing 67.2 25.5 3.5 2.7 0.7 9.5 83.4 33.1 4.6 3.4 1.1 12.4 78.8 42.6 4.2 5.0 1.2 16.0 97.1 56.7 6.0 7.3 1.9 21.6 17.8 2.6 1.2 0.1 0.2 1.1 23.0 3.8 1.7 0.1 0.3 1.4 49.9 22.8 2.4 2.6 0.6 8.4 60.4 29.3 2.9 3.3 0.8 11.0 78.8 42.6 4.2 5.0 1.2 16.0 97.1 56.7 6.0 7.3 1.9 21.6 13.1 8.4 7.7 8.2 3.1 8.1 13.9 9.3 7.9 8.7 3.6 9.1 14.9 10.6 8.8 9.8 4.3 10.0 15.5 11.5 9.8 10.8 5.1 11.1 9.1 0.1 11.5 0.1 16.0 0.2 19.6 0.3 0.2 0.0 0.3 0.0 8.9 0.1 11.2 •0.1 16.0 0.2 19.6 0.3 10.1 23.0 11.4 24.7 14.2 28.1 15.4 31.2 Developed North America Western Europe EEC Other Western Europe Erstern Europe & OSSR Eastern Europe Oceania Other developed 42.2 5.5 13.6 8.7 4.9 11.2 3.1 0.3 11.7 50.3 6.2 15.1 9.6 5.5 14.5 4.1 0.4 14.1 36.3 4.9 8.2 4.8 3.4 11.6 2.2 0.3 11.2 40.4 5.7 9.1 5.3 3.8 13.0 2.6 0.4 12.2 15.2 1.8 6.7 4.5 2.1 3.4 1.8 0.1 3.3 19.2 2.0 7.8 5.2 2.6 4.8 2.3 0.1 4.5 27.0 3.7 6.9 4.2 2.8 7.9 1.2 0.2 8.4 31.1 4.2 7.3 4.4 2.9 9.7 1.8 0.3 9.6 36.3 4.9 8.2 4.8 3.4 11.6 2.2 0.3 11.2 40.4 5.7 9.1 5.3 3.8 13.0 2.6 0.4 12.2 24.5 15.7 19.1 16.2 26.1 22.1 11.5 14.4 62.1 26.6 16.7 19.7 16.8 26.5 25.5 15.9 14.4 64.3 28.5 18.0 21.4 18.2 28.8 28.1 18.7 15.2 66.4 29.6 19.4 23.1 19.6 30.8 29.6 20.8 16.2 64.8 a Excluding denand for meal Source: FAO Agricultural Commodity Projections (Quoted from Robinson, 1980) Food (million tons) Consumption Projeoted demand Food (kg/per capita) Consumption Projected demand 1972-74 1980 1990 2000 1972-74 1980 1990 2000 T ab le 1 -3 . A q u atic O rganism s — A ctu al and E stim a te d P ro d u c tio n P ro d u c tio n ( m illio n to n s ) 1963a 1975b 1980 1990 V orld D eveloping c o u n tr ie s L a tin America A fric a Near E a st F a r E a st A sian c e n t r a l l y planned O ther d ev elo p in g 47.7 2 2 .8 8 .9 2.1 0 .5 5 .3 5 .9 0.1 7 2 .5 34.1 7 .7 3 .8 0 .8 11.2 10.3 0 .3 84 .7 37.3 7 .6 4.1 1 .0 12.6 11.5 0 .5 Developed c o u n tr ie s N orth America W estern Europe EEC O th er W estern Europe E a s te rn Europe & USSR O ceania O ther developed 2 4 .9 4 .0 8 .9 4 .2 4 .7 4 .6 0.1 7 .2 3 8 .4 4.1 11.5 5 .3 6 .2 11.3 0 .2 11.3 3 8 .0 4 .9 11.7 5 .2 6 .5 10.6 0 .3 10.6 8 4 .7 45.6 9 .0 5.1 1 .3 15.6 13.8 0 .7 39.1 6 .4 12.5 5 .3 7 .2 9 .7 0 .4 10.1 2000 R ate o f in c r e a s e ( J /y e a r ) 2000 1974-76 1980 1990 1980 1990 1974-76 1961-65 9 2 .5 5 1 .9 10.2 6 .0 1 .5 18.1 15.3 0 .7 3 .6 3 .4 - 1 .2 6.1 4 .3 6 .4 4 .8 10.7 0 .7 1.8 - 0 .4 1.5 3 .9 2 .4 2.1 8 .6 1 .2 2 .0 1 .7 2 .2 2 .8 2 .2 1 .9 3 .8 0 .9 1.3 1 .2 1.8 1 .9 1.5 1 .0 1 .0 40.6 6 .9 12.9 5 .5 7 .4 10.0 0 .6 10.2 3 .7 0.1 2 .3 2 .0 2 .3 7 .7 3 .8 3 .8 - 0 .2 3 .7 0.1 - 0 .4 1 .0 - 1 .3 8 .7 - 1 .3 0 .3 2 .7 0 .7 0.1 1.1 - 0 .8 4 .8 - 0 .5 0 .4 0 .9 0 .3 0 .4 0 .3 0 .3 4.1 0.1 a 1963 = av erag e 1961-65 b 1975 = av erag e 1974—76 S o u rce: FAO A g r ic u ltu r a l Commodity P r o je c tio n s (Q uoted from R obinson, 1980) 2000 1974-76 ' 1 .0 1.7 1.1 1.8 2 .7 1.9 1.6 3.6 0 .2 2.1 0 .4 0.1 0 .7 - 0 .5 5 .3 - 0 .4 r e s o u r c e w a s te , b u t a l s o t o I n c r e a s e w o rld f i s h p r o d u c t i o n i n o r d e r t o m eet th e i n c r e a s i n g c o n su m p tio n . I t is a re s t i l l c o n c e iv a b l e t h a t an i n c r e a s e i n u n c o n v e n tio n a l s p e c i e s w hich u n e x p lo ite d c o n v e n tio n a l s t o c k s . c o u ld ease a b it of th e p re ssu re on th e M o reo v er, we c a n e x p e c t an in o r e a s e i n a q u a c u ltu r e p r o d u c tio n , w hich a t p r e s e n t o n ly r e p r e s e n t s a b o u t 6 p e r o e n t o f t o t a l w o rld fin fis h p ro d u c tio n , an d we c a n e x p e o t f u t u r e g r o w th i n t h e p r o d u c tio n o f f r e s h w a t e r f i s h e r i e s . T he G r e a t L a k e s , a s o n e o f t h e l a r g e s t f r e s h w a t e r r e s o u r c e s i n th e w o r ld , p la y s a n im p o r ta n t r o l e i n p ro d u c in g f r e s h w a te r f i s h . I t m ig h t i n c r e a s e its s h a r e o f t h e w o r ld p r o d u c t i o n w i t h p r o p e r m anagement and t h e s u p p o r t o f a l l o t h e r f i s h e r y c o n c e rn s . An O verview o f t h e F is h e r y S i t u a t i o n , i n th e G re a t L akes2 T he G r e a t L a k e s , co m p o sed o f L ak e M ic h ig a n , Lake S u p e r i o r , Lake E r i e , Lake H uron, Lake O n ta r io , and Lake S t . C l a i r , h av e a s u r f a c e a r e a o f a p p r o x im a te ly 9 4 ,7 1 0 s q u a r e m i le s ( s t a t u t e ) w hich c o n t a i n s a b o u t 1 /5 o f th e s u r f a c e f r e s h w a te r i n t h e w o r ld . About tw o t h i r d s o f t h e G r e a t L a k e s a r e a i s i n th e U .S . and o n e t h i r d i s i n C anada. About two t h i r d s o f th e U .S. a r e a i s i n M ich ig an w ith 3 8 ,5 7 5 s q u a r e m ile s o f s u r f a c e a r e a and o v e r 3»100 m ile s o f c o a s t l i n e . T he G r e a t L akes ( G .L .) f i s h e r y h a s b e e n a u n iq u e o a se o f re n e w a b le r e s o u r c e ( b i o l o g i c a l r e s o u r c e ) u s e and r e g u l a t i o n . The t o t a l o a t c h by w e ig h t i n M ich ig an w a te r s h a s re m a in e d s t a b l e o v e r th e l a s t one h u n d red ^ T h is s e c t i o n i s h e a v i l y draw n fro m : (1 9 6 8 ), T alh elm (1 9 7 8 ). V .J . C h r i s t i e (1 9 7 4 ); S m ith 10 y e a r s w ith c l o s e t o 30 m i l l i o n pounds p e r y e a r . c o m p o s itio n h a s H o w e v e r, e x p e rie n c e d a c o n tin u o u s c h a n g e . th e s p e c ie s O v e rfis h in g i s c o n s id e r e d a s i g n i f i c a n t f a c t o r i n th e s u c c e s s i o n o f s e v e r a l s p e c i e s , b u t th e p r o c e s s h a s b e e n a c c e l e r a t e d by in v a d in g s p e c i e s and d e g r a d a tio n o f th e e n v iro n m e n t. T he a b u n d a n c e o f many s p e c i e s h a s c h a n g e d d r a m a t i c a l l y . c h a n g e , ho w ev er, d id n o t c a u s e d r a s t i o d e c l i n e i n th e t o t a l f i s h F is h e r m e n s im p l y s h i f t e d s p e o ie s . s m e lt, s p e c ie s T h is o a tc h . t o o t h e r s p e c i e s i n t h e a b s e n c e o f premium H a r v e s tin g te n d e d to w a rd s m a l l e r f i s h s u c h a s y e llo w p e rc h , an d a l e w i f e w h ic h h a v e l o w e r m a r k e t v a l u e s t h a n t h e premium (su c h a s la k e t r o u t ) , a n d i n e f f e o t may h a v e r e d u o e d th e f i s h e r m e n 's g r o s s r e v e n u e . O v e r f is h in g Lake s t u r g e o n , l a k e h e r r i n g , a n d l a k e w h i t e f l s h w e r e among t h e s p e c ie s a p p a re n tly a ffe c te d by o v e r f is h in g . L ak e s t u r g e o n w as o v e r e x p l o ite d n o t due t o i t s h ig h v a lu e b u t b e c a u s e f is h e r m e n w a n te d t o re m o v e th em fro m t h e f i s h i n g g ro u n d s i n o r d e r t o b e a b le t o c a tc h more v a l u a b le f i s h . On t h e o t h e r h a n d , t h e c o l l a p s e o f t h e l a k e h e r r i n g s t o c k s m ig h t h a v e b e e n c a u s e d by i n t e n s e i n t e r a c t i o n w ith e n v iro n m e n ta l o h an g e. w h ite fls h s to c k s w ere a l s o e x p l o i t a t i o n and p o s s ib le T he c o l l a p s e of th e la k e a p p a r e n t l y d u e t o o v e r f i s h i n g a f t e r th e develo p m en t o f th e d eep t r a p n e t , i n t h e e a r l y 1 9 2 0 's , w h ic h w as v e r y e f f i c i e n t f o r c a t c h in g la k e w h i t e f l s h . T he r e c o v e r y o f p rem iu m s t o c k s ( l a r g e r s p e c i e s ) d o es n o t alw ays o c c u r ev en th o u g h th e f i s h i n g p r e s s u r e e a s e s . T h is i s m a in ly due t o th e f a c t t h a t a f t e r th e premium s t o c k s c o l l a p s e , s m a lle r s p e c ie s in s iz e s , t h e sam e a r e a . th e f is h e r y s h ifts a F ish e rm e n u se s m a lle r g i l l n e t mesh s o t h a t t h e y o u n g e r o f t h e l a r g e r s p e c i e s m ay b e t o g e t h e r w ith s m a lle r s p e c ie s . to T h is , in e f f e c t , c a p tu re d may s u p p r e s s t h e premium s p e c ie s p e rm a n e n tly a s i n th e c a s e o f d e e p w a te r c i s c o e s . The I n v a s io n o f S e a Lamprey The in v a s i o n an d e x p a n s io n o f s e a la m p re y , w h ic h p r o b a b l y cam e by way o f t h e s h i p p i n g c a n a l a r o u n d N ia g a r a F a l l s , had e x te r m in a te d la k e t r o u t i n Lake Huron and Lake M ich ig an i n t h e l a t e 1 9 5 0 's . Lake t r o u t i n L a k e S u p e r i o r , w h i t e f l s h an d o t h e r s p e c i e s i n L a k e H u ro n a n d L ake M ich ig an w ere a l s o s e r i o u s l y a f f e c t e d . The m o r t a l i t y o f t r o u t c a u s e d by s e a la m p rey was e s ti m a t e d a t a b o u t 70 p e r c e n t a n n u a lly i n L akes M ich ig an and H uron. A fte r th e c o lla p s e o f la k e t r o u t , la k e w h i t e f l s h became p r e y f o r th e s e a la m p re y , w h ich re d u c e d t h e w h i t e f l s h p o p u l a t i o n s t o c k . m o re f a v o r e d p r e y , l a k e t r o u t an d w h i t e f l s h , As t h e b ecam e s c a r c e t h e s e a la m p rey a t t a c k e d la k e h e r r i n g , w h ite s u c k e r s and many o t h e r s p e c i e s . T he s e a la m p r e y i n v a s i o n , i n a d d i t i o n t o o v e r f i s h i n g , c o n t r i b u t e d t o th e d e c l i n e o f w h i t e f l s h p r o d u c t i o n i n t h e G .L . t o a lo w o f 0 .1 m i l l i o n pounds i n 1942 from o v e r 4 .1 m i l l i o n pounds i n 1931* As a r e s u l t o f th e c o l la p s e o f many f i s h s p e c i e s , t h e c o m p o s i t i o n o f f i s h s to c k and s p e c i e s i n th e G .L. ch an g e d . d eep w a te r p r e d a t o r s w e r e d e p l e t e d . s m a ll s p e c ie s su ch as s m e lt, s to c k s i n c r e a s e d . Lake t r o u t , b u r b o u t, and As a r e s u l t o f t h e d e p l e t i o n s , deep w a te r c is c o ( c h u b s ) , and a le w ife Lake h e r r i n g s to c k s a l s o d e c r e a s e d i n r e s p o n s e t o th e 12 s m e lt I n c r e a s e . A le w ife I n c r e a s e d r a p i d l y and d o m in a te d t h e f i s h s to c k s I n Lake H uron and Lake M ich ig an . D e g r a d a tio n o f E n v iro n m en t The e f f e c t o f e n v i r o n m e n t a l d e g r a d a t i o n may h a v e m a g n i f i e d t h e p ro b le m s f a c e d by f i s h s p e c ie s on th e G .L . T h e d i s c h a r g e an d a c c u m u la tio n o f m i l l i n g w a s te s fro m t h e l u m b e r i n g i n d u s t r i e s o f L a k e s H u ro n , M ic h ig a n an d S u p e r i o r , f o r i n s t a n c e , a p p a r e n tly h ad s e rio u s e f f e c t s o n r e p r o d u c t io n o f some s p e c i e s su c h a s l a k e w h i t e f l s h a n d l a k e h e rrin g . T he c o n s t r u c t i o n o f dams b lo o k e d sp aw n in g m i g r a ti o n and d e s tr o y e d o f spaw ning a r e a s . D e f o r e s t a t i o n o f th e d r a in a g e b a s i n c a u s e d r e d u c e d flo w s a t c r i t i c a l tim e s f o r th e f i s h , an d a l a r g e number o f s tr e a m s became u n in h a b ita b l e b e c a u s e o f i n c r e a s e d t e m p e r a t u r e s a n d h e a v y s i l t b u rd e n s. H a t e r e u t r o p h l c a t i o n c a u s e d by p l a n t n u t r i e n t w a s te h a s a t tim e s t a k e n l a r g e e x p a n s e s o f w a t e r o u t o f f i s h p r o d u c tio n th ro u g h oxygen d e p l e t i o n . E u t r o p h l c a t i o n a l s o e n c o u r a g e s s p e c i e s c o m p o s itio n c h a n g e s . It f a v o r s th e s p e c i e s h a v in g th e b e s t t o l e r a n c e f o r n u t r i e n t - e n r i c h e d w a te r su c h a s s m e lt and y e llo w p e rc h . The d o m in a tio n o f Lake E r i e by th e s e s p e c i e s r e f l e c t s th e t o l e r a n c e s o f th e s e s p e c i e s . A f t e r s e a la m p r e y w as b ro u g h t u n d e r c o n t r o l by r e d u c in g i t s s to c k i n th e m id 1 9 6 0 's , l a k e e s ta b lis h t r o u t a n d s a lm o n w e re p l a n t e d i n t o a new s p e c i e s b a l a n c e o f m ore p r e f e r a b l e s to c k i n g program h a s r e s u l t e d f i s h e r y o n th e G .L . in G .L . t o s p e c ie s . T h is th e e s ta b lis h m e n t o f a la r g e sp o rt W h ite f ls h and w h ite s u c k e r co m m ercial c a t c h e s h av e 13 a l s o im p ro v ed s i g n i f i c a n t l y . However, i n t h e l a t e 1 9 6 0 's a n d DDT ( D i o h l o r o d i p h e n y l - t r i c h l o r o - e t h a n e ) u s e d as 1 9 7 0 's , p e s tic id e in a g r i c u l t u r e , PCB ( p o l l c h l o r i n a t e d b ip h e n y l) s i m i l a r t o DDT, m e r c u r y a n d o t h e r p o is o n s w e re fo u n d t o c o n ta m in a te many o f t h e f i s h o n th e G .L ., p a r t i c u l a r l y s a lm o n id s . As a r e s u l t o f t h i s c o n ta m in a tio n , t h e c o m m e r c ia l s a l e o f coho salm o n , o h in o o k salm on an d la k e t r o u t w e r e b a n n e d by t h e g o v e r n o r s o f M ic h ig a n a n d W i s c o n s i n . T he l e v e l o f c o n ta m in a tio n w as so h i g h , t h a t M ich ig an r e s i d e n t s w ere w arn ed n o t t o e a t some G r e a t L a k e s f i s h f o r m ore t h a n o n e m eal a w eek. T h is c a u s e d a c o n s i d e r a b l e econom ic l o s s f o r th e oom m ercial f i s h e r i e s , w hich a l r e a d y w ere i n a d e p r e s s e d s i t u a t i o n . P ro b lem s o f M ic h ig a n 's G r e a t L ak es (G .L .) Com m ercial F is h e r s : T he c h a n g e i n t h e f i s h c o m p o s itio n on th e G .L . away from t h e m ore v a l u a b le and p r e f e r a b l e o v e rfis h in g , s p e c ie s to th e l e s s v a lu a b le (m a in ly d u e to s e a la m p r e y d i s r u p t i o n , and e n v iro n m e n t d e g r a d a tio n ) h a s c a u se d d e t e r i o r a t i o n o f M ic h ig a n 's co m m ercial f i s h e r i e s . T h is s i t u a t i o n h a s b e e n h a s te n e d by th e c o m p e titio n w ith s p o r t f i s h i n g . E s tim a te s o f th e p u b l i c r e c r e a t i o n a l v a l u e s o f t h e f i s h e r y r e s o u r c e a r e m o re th a n t e n tim e s g r e a t e r th a n co m m ercial v a l u e s (T a lh e lm , 1 9 7 8 ), and p u b lic p o l i c y T h e re fo re , had changed m o re i n th e c o m p o s itio n o f f i s h c a tc h i s r a t h e r th a n co m m ercial a l th o u g h t h e t o t a l re c e n t y e a rs s p o rt fis h in g fa v o r of sp o rt fis h in g . s h i f t i n g m o re t o s p o r t c a tc h h a s n o t ohanged. In h a r v e s t e d a b o u t t h r e e t i m e s t h a t o f th e com m ercial c a to h from th e t o t a l G .L. c a to h o f 60 m i l l i o n pounds. r e s t r i c t i o n s and r e g u l a t i o n s h a v e b e e n p la c e d n o t o n ly t o Many p re v e n t 14 o v e r f i s h i n g an d t o r e s t o r e d e p l e te d p o p u la tio n o f s p o r t a n d c o m m e r c ia l f i s h , b u t a l s o t o g i v e m ore l e v e r a g e f o r s p o r t f i s h i n g . I n 1968, th e M ich ig an l e g i s l a t u r e g r a n te d th e M ic h ig a n D e p a r tm e n t o f N a t u r a l R e s o u r c e s (MDNR) a u t h o r i t y t o l i m i t e n t r y i n t o th e f i s h e r y . S in c e th e n th e MDNR h a s im posed s e v e r a l r e s t r i c t i o n s su c h a s : - R e s t r i c t e d l i c e n s e s t o f u l l - t i m e f is h e r m e n - A zo n e m anagement program - S t r i n g e n t g e a r r e s t r i c t i o n s f o r i n d i v i d u a l fis h e rm e n - Banned c e r t a i n g e a r ty p e s i n v a r io u s zo n e and w a te r d e p th s . - A llow ed no co m m ercial f i s h i n g i n n o n -co m m ercial zo n e s - R e s t r i c t e d th e s p e c i e s w h ich c a n b e c a u g h t, e t c . T he M io h ig a n D e p a r tm e n t o f N a tu r a l R e s o u rc e s a l s o p ro p o se d t o buy o u t a l l l a r g e mesh an d m ost s m a ll mesh g l l l n e t i n 1 9 7 4 . T h en g i l l n e t s w e re t o b e b a n n e d i n o r d e r t o e l i m i n a t e th e i n c i d e n t a l c a to h o f la k e tr o u t f o r th e p u rp o se o f r e h a b i l i t a t i n g th e la k e tr o u t p o p u la tio n . F is h in g l i c e n s e s w ere re d u c e d from 300 i n 1969 t o a b o u t 140 i n 1970. T h e re i s v e r y l i t t l e ch an ce t h a t M ic h ig a n 's co m m ercial f i s h e r y , w e l l a s t h e U .S . G r e a t L a k e s c o m m e r c ia l f i s h e r y , fu tu re . as w i l l ex p an d i n th e C om m ercial f i s h e r i e s d ep en d h e a v i l y on t h e - s t a t e ' s w i l l i n g n e s s to a llo c a te f is h t o them and a r e s t r o n g l y a f f e c t e d by c o n ta m in a tio n o f o e r t a i n f i s h s p e c i e s ( C o m p tr o lle r G e n e ra l o f th e U . S . , 1977)* C a n a d a , w h ic h s h a r e s a l l G r e a t L a k e s w i t h t h e U .S . e x c e p t Lake M ich ig an , i s e x p e r i e n c in g th e p ro b lem s fa c e d by M i c h i g a n 's G r e a t L a k e s fis h e ry re so u rc e s. c o m m e r c ia l f i s h i n g H o w e v e r, i n t h e c o m m e r c ia l s e c t o r , th e C an ad ian in d u s try h as n o t been a ffe c te d by s u c h i n t e n s e c o m p e t i t i o n fro m s p o r t f i s h i n g o r by r e s t r i c t i v e g o v ern m en t r e g u l a t i o n a s t h e i r U .S . c o u n t e r p a r t . As a r e s u l t , s i n c e 19 7 5 , C a n a d a , w h ic h h a s 15 o n ly a b o u t 36 p e r c e n t o f G re a t L ak es w a t e r s , fis h v a l u e t h a n t h e U .S . w id e n e d o v e r t h e y e a r s , M o re o v e r, p r o d u c e s m o re c o m m e rc ia l a s show n I n T a b l e 1 - 4 . g ro w in g to m o re th a n T hese d if f e r e n c e s tw o f o l d by 1982. th e g ap d o es n o t o c c u r o n ly i n v a l u e , b u t a l s o i n p r o d u c tio n . T he U n i t e d S t a t e s l a n d i n g s h a v e d e c r e a s e d a b o u t 23 p e r c e n t w h ile C a n a d a 's in c r e a s e d a b o u t 65 p e r c e n t o v e r th e same p e r io d . T a b le 1 - 4 . Y ear The V alue o f th e U .S . and C an ad ian C om m ercial F is h in g C atch from t h e G r e a t L akes 1975 - 1982 ( i n M illio n ) U .S .______________ Q u a n tity ( l b ) V alue ($ )* 1975 1976 1977 1978 1979 1980 1981 1^82 C anada Q u a n tity ( l b ) V alu e ($ ) 9 .0 1 0 .5 10.1 1 0 .4 12.6 1 2 .0 1 5 .4 ‘ 1 3 .8 6 1 .7 6 6 .7 72.8 70 .0 5 5 .5 3 8 .5 4 8 .3 4 7 .6 4 5 .4 4 1 .1 5 1 .9 5 6 .0 5 5 .4 5 9 .0 6 1 .9 7 5 .2 11.1 1 2 .5 1 4 .6 1 7 .2 26.1 2 3 .5 31.8 3 6 .8 *The d i f f e r e n c e s i n v a lu e o f U .S . and C an ad ian d o l l a r s a r e n o t a d j u s t e d . What h a s b een shown i n T a b le 1 -4 may i n d i c a t e p u b lic th e d if f e r e n c e s in p o l i c y a p p r o a c h e s t o m a n a g in g f i s h e r y r e s o u r c e b e tw e e n tw o c o u n t r i e s w h ich s h a r e t h e sam e r e s o u r c e s . C a n a d a , w h ic h o p e n s m ore a c c e s s t o co m m ercial f i s h e r y i n i t s w a t e r s , h a r v e s t s m ore f i s h and f i s h o f much h ig h e r v a lu e . On th e o t h e r h a n d , t h e U .S . w h ic h im p o s e s m ore r e s t r i c t i o n s o n c o m m e rc ia l f i s h i n g , p ro d u c e s l e s s com m ercial f i s h th a n C anada. 16 The P ro b le m S ta te m e n t M ic h ig a n G r e a t L a k e s c o m m e r c ia l f i s h e r y r e s o u r c e s , a s m e n tio n e d e a rlie r, f a c e many p r o b l e m s , w h e th e r i t ' s change in th e b io l o g ic a l c o m p o s i t i o n , e n v iro n m e n t, c o m p e titio n w ith s p o r t f i s h i n g , p u b lio p o li c y o r by f i s h e r m e n t h e m s e l v e s who a p p a r e n t l y t e n d t o o v e r f i s h . T hese p ro b lem s w ould a f f e c t t h e n a t u r e o f p o lio y i n m anaging f i s h e r y r e s o u r c e s a s w e ll a s p r i c e s . F i s h e r y p r i c e s a r e a f f e c t e d by a g r e a t number o f f o r c e s . Volumes o f f i s h la n d e d , t a s t e s and p r e f e r e n c e s o f th e co n su m ers, q u a l i t y o f f i s h la n d e d , c o n su m e r in c o m e s , v a rie tie s of fis h la n d e d , le v e l of c o n ta m in a n ts i n t h e f i s h , th e a v a i l a b i l i t y o f s u b s t i t u t e s , an d c o s t s o f f is h h a rv e s tin g a l l a f f e c t f i s h p r ic e s . P o l i c i e s an d r e g u l a t i o n im posed by g o v e rn m e n t a g e n c i e s i n m a n a g in g t h e r e s o u r c e a ls o a f f e c t p ric e s th ro u g h t h e i r i n f l u e n c e s o n m a rk e t demand and s u p p ly . The f u t u r e o f th e M iohigan G re a t L akes c o m m e rc ia l f i s h e r y d e p e n d s o n t h e e x t e n t t o w hich th e s t a t e w a n ts t o d e v e lo p and m a in ta in a v i a b l e com m ercial f i s h e r y ( C o m p tr o lle r G e n e r a l, 1977)* p iv o ta l ro le in d u s try . S ta te a g e n c ie s hav e a i n s e t t i n g p o l i c i e s w h ic h a f f e c t t h e co m m ercial f i s h e r y L ack o f i n f o r m a t i o n , u n d e r s t a n d i n g an d s p e c i f i c k n o w le d g e a b o u t t h e s o c io - e c o n o m ic a s p e c t s o f t h e co m m ercial f i s h e r y r e q u i r e d t o im prove upon th e p o li c y o f f i s h e r y r e s o u r c e u t i l i z a t i o n may ham per t h e i r e f f o r t to a t t a i n e f f ic ie n c y . As m e n tio n ed by Haveman (1 9 7 3 ), th e n a t u r e o f n a t u r a l r e s o u r c e u s e w hich i s a s s o c i a t e d w ith t h e com m ons, e x t e r n a l d is e c o n o m i e s , and p u b l i c goods i s d o m in ated by m a rk e t f a i l u r e . p o lic y d e c is io n s to th e p riv a te s e c to r, L e a v in g w ith o u t any g o v e rn m e n t 17 in te r v e n tio n to c o r r e c t t h i s f a i l u r e , may r e s u l t i n i n e f f i c i e n c y , e c o n o m ic w a s t e , m i s a l l o o a t i o n , an d o v e r p r o d u c t i o n o f t h e r e s o u r c e . However p u b li o p o l i c y a lo n e w ith o u t r e l y i n g on econom ic v a l u e s m ig h t n o t a lle v ia te t h e p r o b le m . I t m ig h t g e n e r a te a n o th e r i n e f f i c i e n c y th ro u g h th e r e g u l a t o r y sy ste m i n c o n t r o l l i n g r e s o u r c e u s e . p ro v id e m o re i n f o r m a t i o n R e s e a rc h t h a t c o u ld a b o u t e c o n o m ic a s p e c t s a s w e ll a s th e b i o l o g i c a l n a tu r e o f t h e f i s h e r y r e s o u r c e may h e l p rem edy th e p ro b lem o f l a c k o f i n f o r m a t i o n , a n d e n h a n c e t h e p u b l i c p o l i c y d e c i s i o n m aking p ro c e ss. L ittle r e s e a r c h h a s b e e n c o n d u c t e d o n t h e e c o n o m ic a s p e c t s o f c o m m e r c ia l f i s h e r i e s o n M i c h i g a n 's G r e a t L a k e s k n o w le d g e ) . B ecau se o f t h i s , (to th e a u t h o r 's an y r e s e a r c h o r s t u d y on t h e econom ic a s p e c t s o f co m m ercial f i s h e r i e s w i l l p r o v i d e v a l u a b l e i n f o r m a t i o n t o in d iv id u a ls , o r g a n i z a t i o n s a n d p u b li c a g e n c ie s . T h is in f o r m a tio n can a i d i n th e u n d e r s ta n d in g and p l a n n i n g b e t t e r u s e s o f t h e G r e a t L a k e s f is h re so u rc e s. The O b je c t iv e s o f t h e S tu d y I t i s ack n o w led g ed t h a t th e M ich ig an G r e a t L ak es co m m ercial f i s h i n g in d u s tr y i n g e n e ra l i s i n a d ep re sse d s i t u a t i o n . T h ere a r e many f a c t o r s t h a t h av e c o n t r i b u t e d t o th e p ro b le m s f a c e d by th e i n d u s t r y . T h e re fo re , t h i s stu c fr i s d e s ig n e d t o e x p l o r e , t o some e x t e n t , how f i s h p ro d u c tio n h as been a ffe c te d by t h o s e f a c t o r s o v e r tim e , and t r y t o e s ti m a t e th e optim um s u s t a i n a b l e y i e l d s . The s t u d y a l s o w i l l d i s c u s s t h e f a c t o r s w hich a f f e c t M ich ig an f i s h p r i c e s and t h e i r r e l a t i v e im p o rta n c e . 18 By a n a l y z i n g p r i c e s t h i s r e s e a r c h may p ro v id e v a l u a b le in f o r m a tio n f o r t h e f is h e r m e n , f i s h p r o c e s s o r s , w h o le s a le r s , p u b l i c a g e n c ie s an d th e p u b lic in g e n e ra l w ho a r e c o m m e r c ia l f i s h e r y . q u a n titie s i n e c o n o m ic a s p e c t s o f t h e By k n o w in g w h a t f a c t o r s a ffe c t p ric e s and p u r c h a s e d o r t h e t r e n d o f p r i c e s an d q u a n t i t i e s o v e r tim e , th e y c a n t o p o te n tia l in te re s te d som e e x t e n t , f o r th e f i s h changes r e s u ltin g fro m p r e d ic t th e f u tu r e p ro d u c ts . changes o o u rse of th e m a rk e t T h ey a l s o may d e t e r m i n e r e v e n u e in th e q u a n tity o f fis h e s s o ld . M o r e o v e r , t h i s i n f o r m a t i o n may i n f l u e n c e m a r k e t e x p a n s i o n e f f o r t s . A lth o u g h t h i s s tu d y may n o t s o lv e th e p ro b le m s f a c e d by t h e c o m m e r c ia l f i s h i n g I n d u s t r y , i t may p r o v id e a b e t t e r u n d e r s ta n d in g o f t h e s i t u a t i o n i n th e i n d u s t r y . The m ore s p e c i f i c o b j e c t i v e s o f t h i s s tu d y a r e : 1. To e s t i m a t e t h e b io e c o n o m ic v a l u e s o f t h e M io h ig a n G r e a t L ak es C om m ercial F i s h e r y . 2. To e s t i m a t e and a n a ly z e th e demand and s u p p ly o f s e v e r a l f i s h s p e c ie s . 3. To e s t i m a t e th e e l a s t i c i t i e s b etw ee n r e s o u r c e s and p r i c e s a s w e l l a s incom e and p r i c e f l e x i b i l i t y . 4. To e s t i m a t e th e p o t e n t i a l c o n su m e r, p ro d u c e r and s o c i a l s u r p l u s o f co m m ercial f i s h e r y . F is h S p e c ie s t o be S tu d ie d F iv e f i s h s p e c i e s w i l l be a n a l y z e d i n t h i s s tu d y b a se d on th e h i g h e s t c a tc h and v a lu e d u r in g th e p e r io d o f 1960 - 1982. are: T hese s p e c i e s 19 1. W h ite f ls h (C o reg o n u s o lu p e a f o r m is ) 2. Chubs (C o reg o n u s h o y i) 3. Y ellow P e rc h ( P e r e a f l a v e s c e n s ) 4. C a t f i s h ( X c ta lu r u s p u n c ta tu s ) 5. A le w ife (A lo s a p s e u d o h a re n g u s ) The a r e a i n c l u d e d i n M ic h ig a n S t a t e th is ju ris d ic tio n ; s tu d y i s t h e w h o le G r e a t L a k e s u n d e r i n c l u d i n g p o r t i o n s o f L a k e s M ic h ig a n , S u p e r io r , H uron, E r i e , and S t . C l a i r . O r g a n iz a tio n o f th e S tu d y T h is s tu d y is d iv id e d in t o s e v e ra l c h a p te rs . C h a p te r I , th e I n t r o d u c t i o n , b r i e f l y d e s c r i b e s th e s i t u a t i o n o f w o rld f i s h e r y r e s o u r c e , a n d M ic h ig a n G r e a t L ak es co m m ercial f i s h e r y i n d u s t r y . I t a lso la y s o u t th e s tu d y fram ew ork i n w hich th e p ro b lem s ta te m e n t and s tu d y o b j e c t i v e s a r e p r e s e n te d . C h a p te r I I re v ie w s th e l i t e r a t u r e o n t h e s u b j e c t o f b io e c o n o m ic a p p ro a c h , demand and s u p p ly , m anagement o f co m m e rc ia l f i s h e r y , a s w e ll a s th e p r e v io u s s t u d i e s w h ich h av e b een c o n d u c te d i n th e s e f i e l d s . C h a p te r I I I in t r o d u c e s th e r e s e a r c h m eth o d s and p r o c e d u r e s u s e d i n t h i s s tu d y . C h a p t e r IV p r o v i d e s t h e d e s c r i p t i o n and a n a l y s i s t h e s t a t e o f th e M ich ig an G r e a t L akes com m ercial f i s h e r y fro m 1960 -1 9 8 2 . C h a p te r V p r e s e n ts th e e s tim a tio n p a r a m e te r s o f s e v e r a l c o m m e r c ia l f i s h o f t h e b io e c o n o m ic m o d e l c o m m o d itie s i n M ic h ig a n ; a n d C h a p t e r V I p r e s e n t s t h e e s t i m a t i o n o f demand and s u p p ly p a r a m e te r s f o r th e same f i s h c o m m o d itie s. GREAT LAKES FISHERY LEGEND raffia MICHIGAN MINNESOTA WISCONSIN ?0°o0o°pp LAKE SUPERIOR NEW YORK OHIO MINNESOTA EPPI ILLINOIS 533 PENNSYLVANIA O N T A R IO ■ ■ MICHIGAN NO R TH CHA NNEL INDIANA ran CANADA S i* WISCONSIN S T . LAW RENCE R IV E R ^ T a k e On t a r io I f*:*: LAKE S T .C L A IR NEW YORK !-■ I PENNSYLVANIA F ig u re 1 -2 . G reat Lakes F is h e ry 21 C h a p t e r V I I g i v e s a summary o f t h e s tu d y , p r e s e n t s th e c o n c lu s io n and reco m m en d atio n s. CHAPTER I I REVIEW OF LITERATURE T h is c h a p t e r w i l l r e v ie w and d i s c u s s t h e l i t e r a t u r e d e a lin g w ith t h e d e v e lo p m e n t o f b i o l o g i c a l and econom ic a p p ro a c h e s t o th e m anagement o f fis h e ry re so u rc e s. I t w i l l a l s o d e s c r i b e th e r o l e o f econom ic th e o r y w h ic h , w hen a p p l ie d i n t o th e b i o l o g i c a l c o n c e p t o f f i s h e r y , r e s u l t e d i n a new ap p ro a c h c a l l e d b io e c o n o m io m o d e lin g . T he a p p l i c a t i o n s o f t h e b io e c o n o m ic m o d e l i n e m p ir ic a l s t u d i e s c o n d u c te d p r e v io u s l y a s w e l l a s s t u d i e s on th e demand an d s u p p ly o f t h e c o m m e r c ia l f i s h e r y c o m m o d ity , w i l l a l s o be d is c u s s e d i n t h i s c h a p t e r . G o rd o n 's (1 9 5 4 ) i n i t i a l w o rk t o th e o ry in i n t r o d u c e t h e r o l e o f e c o n o m ic t h e m an ag em en t o f f i s h e r y r e s o u r c e s w hich had b een d o m in ated by b i o l o g i o a l c o n s i d e r a t i o n s m ile s to n e . (M ito h e ll 1979) c a n b e c o n s id e re d a G o r d o n e x a m i n e d t h e r o l e o f e c o n o m ic t h e o r y i n t h e u t i l i z a t i o n o f f i s h e r y r e s o u r c e s w h ich i s v iew ed a s u n u s u a l r e s o u r c e due to i t s b i o l o g i o a l a n d common p r o p e r t y n a t u r e . He m e n tio n s t h a t m ost b i o l o g i s t s ig n o r e d o r d i d n o t g iv e much a t t e n t i o n t o econom ic r a t i o n i n g in t h e m a n ag em e n t o f f i s h e r y reso u rces. T h e ir s o le c o n s id e r a tio n fo c u s e d on m ax im izin g th e number o f f i s h c a u g h t and n e g l e c t i n g th e c o s t s o f fa o to r in p u ts r e q u ir e d f o r th e c a tc h in g e f f o r t . b i o l o g i s t s te n d e d t o recommend e x p l o i t i n g t h e f i s h p o i n t o f maximum s u s t a i n a b l e y i e l d m a rg in a l p r o d u c t i v i t y o f f i s h i n g p o p u la tio n s to th e (MSY) w h ic h i s e f f o r t is z e ro . T h e r e f o r e , th e o b ta in e d when th e On t h e o t h e r h a n d , fro m t h e e c o n o m is ts p o in t o f v ie w , th e optimum f i s h i n g e f f o r t s h o u ld be 22 e x p lo r e d t o t h e l e v e l w h ich c o u ld p r o v id e maximum econom ic y i e l d (MEY). T h u s , f i s h i n g e f f o r t t o p ro d u ce MEY i s l e s s th a n th e e f f o r t t o p ro d u ce MSY. The p o in t o f MEY w i l l o c c u r i n t h e r a n g e o f p r o d u c t i o n i n w h ic h th e s lo p e o f m a rg in a l p r o d u c tiv ity i s p o s itiv e . I n r e a l i t y , h o w ev er, o p en a c c e s s f i s h e r y r e s o u r o e w i l l a p p a r e n t l y b e e x p l o i t e d c o m p e titiv e m a rk e t to in th e f r e e a l e v e l w h e re AC ( a v e r a g e c o s t ) = AR ( a v e ra g e r e v e n u e ) , w hioh i s m o st l i k e l y t o be i n th e ra n g e o f n e g a t i v e m a r g i n a l p ro d u c tiv ity . Thus no econom ic r e n t i s l e f t t o th e f is h e r m e n . The s ta n d a r d b i o l o g i c a l m o d e l o f f i s h e r i e s , w h io h i s u s e d a s a b a s i c d is c u s s i o n i n econom ic t h e o r y , i s th e l o g i s t i c m odel o f p o p u la tio n g ro w th d e v e lo p e d by S o h a e fe r i n t h a t th e u n d e rly in g f i s h 1953* S c h a e f e r ' s m o d e l ( 1 9 5 7 ) sh o w s p o p u l a t i o n g ro w s w hen t h e n a t u r a l r a t e o f g ro w th e x c e e d s th e r e d u c t i o n s from th e e f f e o t s o f b o th n a t u r a l m o r t a l i t y an d f i s h i n g e f f o r t . T h i s c a n b e show n by t h e f o l l o w i n g b i o l o g i c a l m o d e l: dB dt = f (B) ( 2 . 1) Y = y (B , E) ( 2 . 2) B = b (E) ( 2 .3 ) f (B ) = t 1 B(K-B) ( 2 . 1») Y = qEB ( 2 .5 ) w here dB dt = g ro w th o f b io m ass B = b io m ass Y = th e o a tc h o r y i e l d E = fis h in g e f f o r t t-j = c o n s ta n t 24 q s " c a t c h a b i l i t y " o f t h e f i s h w h ich i s a l s o c o n s ta n t K = maximum b io m a ss ( c a r r y i n g o a p a c ity ) In e q u a tio n ( 2 .1 ) S c h a e f e r in d i c a t e s th a t th e r a t e o f n a tu r a l i n c r e a s e o f b io m a ss i s f u n c t i o n o f p o p u l a t i o n s i z e th e c a tc h ( b io m a s s ) , w h e re a s ( l a n d i n g s ) i s f u n c t i o n o f b io m ass and f i s h i n g e f f o r t a s shown i n e q u a tio n ( 2 . 2 ) . T he b io m a s s i t s e l f u n d e r e q u i l i b r i u m a c c o rd in g t o S c h a e fe r i s c o n d itio n , a f u n c t i o n o f f i s h i n g e f f o r t ( e q u a t io n 2 .3 )* I n e q u a tio n ( 2 .4 ) and ( 2 .5 ) S c h a e f e r s p e c i f i e s th e a p p r o x i m a t e f o r m o f b io m a s s g r o w th an d f i s h la n d in g s . In e q u ilib riu m c o n d i t i o n , c a tc h ( la n d i n g s ) e q u a ls th e r a t e o f n a t u r a l i n c r e a s e i n b io m a s s a s sh o w n i n e q u a tio n ( 2 . 6 ) . qEB = t 1 b (K-B) ( 2 .6 ) t h i s e q u a tio n c a n be r e a r r a n g e d a s : B =K - ( q / t ^ ) ( 2 .7 ) e Then " S c h a e f e r 's y i e l d f u n c t i o n " i s d e r i v e d by s u b s t i t u t i n g e q u a t i o n ( 2 .5 ) i n t o ( 2 . 7 ) , g iv i n g : Y = qE (K - ( q / t 1) E) ( 2 .8 ) From e q u a tio n ( 2 . 6 ) , i f th e n a t u r a l r a t e o f g r o w th o f b io m a s s e x c e e d s th e m o r t a li ty ( n a t u r a l and f i s h i n g e f f o r t ) , th e r i g h t hand s i d e o f th e e q u a tio n i s g r e a t e r theui t h e l e f t hand s i d e ; th e n d B /d t i s g r e a t e r t h a n z e r o ; t h e b io m a s s i s g ro w in g . On th e o t h e r h an d , i f b io m ass g ro w th i s l e s s th a n th e m o r t a l i t y , d B /d t i s n e g a t i v e ; F u rth e rm o re , t h e m o d e l sh o w s t h a t i f t h e b io m a s s i s d e o lin in g . f i s h i n g e f f o r t (w h ich c o u ld be m easu red i n te rm s o f th e number o f b o a t s , f is h e r m e n , o r f i s h i n g d a y s ) i s i n c r e a s e d , i t c a n i n c r e a s e y i e l d t o th e l e v e l o f MSY. f u r th e r in c re a s e in e ffo rt w ill re s u lt in Beyond t h i s , any a lo w e r y i e l d due to 25 o v e r f i s h i n g o f t h e f i s h e r y r e s o u r c e s 1 ( M i t c h e l l , 1 9 7 9 ). At t h i s s ta g e th e r e p r o d u c t i v e c a p a b i l i t y o f t h e f i s h p o p u la tio n c a n n o t k eep p a c e w ith th e r a t e o f m o r t a l i t y ( n a t u r a l and m anm ade), th u s t h e p o p u la tio n s to c k w i l l d e c r e a s e a s w i l l th e y i e l d from f i s h i n g e f f o r t P o p u l a t i o n s t o c k a t P2 i s s m a lle r th a n a t P I. (s e e F ig u re I I - 1 ) . B i o l o g i s t s te n d e d t o recom m end e x p l o i t a t i o n a t t h e MSY l e v e l w h ic h p r o d u c e d t h e l a r g e s t am o u n t o f fo o d . From t h e e o o n o m io p o i n t o f v ie w , a s e x p r e s s e d by G ordon, m a x im iz a tio n w i l l be r e a c h e d w hen t h e m a r g i n a l r e v e n u e o f a n e x tra u n it o f fis h c a u g h t e q u a ls m a rg in a l c o s t. G ordon com bined an econom ic m odel w ith a b i o l o g i c a l m odel t o form a b ionom io (b io -e c o n o m ic ) m odel. He tu r n e d t h e p h y s ic a l f i s h p r o d u c tio n f u n c t i o n (w h ich show s th e r e l a t i o n s h i p b e tw e e n y i e l d re v e n u e fu n c tio n . and e f f o r t ) in to th e w e ll behaved t o t a l T h i s w as d o n e by m u l t i p l y i n g t h e p o i n t s o n t h e p r o d u c tio n c u rv e tim e s p r i c e s . By a s s u m in g a c o n s t a n t c o s t f o r e a c h u n i t o f e f f o r t , w hich im p lie s t h a t th e o o s t w i l l i n o r e a s e l i n e a r l y w ith f i s h i n g e f f o r t , th e t o t a l c o s t o f f i s h i n g e f f o r t c a n be r e p r e s e n t e d by a s tra ig h t lin e . The i n t e r s e c t i o n b e tw e e n th e t o t a l re v e n u e c u r v e and t h e t o t a l c o s t c u rv e i n d i c a t e s t h a t a t t h i s ■f i s h i n g e f f o r t i s p o in t th e a v e ra g e re v e n u e o f e q u a l t o th e a v e r a g e c o s t , t h e p o i n t o f lo n g r u n and 1 A o co rd in g t o P a u ly ( 1 9 8 0 ) , o v e r f i s h i n g may h ap p en i n te rm s o f : ( a ) " g r o w th o v e r f i s h i n g , " o c c u r w hen t h e y o u n g f i s h t h a t b e c o m e a v a i l a b l e t o t h e f i s h e r y ( t h e r e o r u i t ) a r e c a u g h t b e f o r e th e y c a n grow t o a r e a s o n a b le s i z e . (b ) " R e c ru itm e n t o v e r f i s h i n g , " o o o u rs when th e ( p a r e n t ) s t o c k i s re d u c e d by f i s h i n g t o th e e x t e n t t h a t n o t e n o u g h y o u n g f i s h a r e p r o d u o e d t o e n s u r e t h a t th e s to c k w i l l m a in ta in i t s e l f . (o ) "E co sy stem o v e r f i s h i n g , " o c c u r s i n m ixed f i s h e r i e s when t h e d e c l i n e ( th r o u g h f i s h i n g ) o f th e o r i g i n a l l y ab u n d an t s to c k s i s n o t f u l l y c o m p e n s a te d f o r by t h e c o n t e m p o r a r y o r s u b s e q u e n t i n c r e a s e o f t h e b io m a s s o f o t h e r e x p l o i t a b l e a n im a ls . E co sy stem o v e r f i s h i n g w ould be th e t r a n s f o r m a t i o n o f a r e l a t i v e l y m a tu r e e f f i c i e n t s y s t e m i n t o a n im m ature i n e f f i c i e n t sy ste m (fro m s t a b l e t o u n s t a b l e low b io m a s s ) . 26 Catch (Yield) MSY Total Sustainable ^ Yield Effort E. ‘opt Figure II-l. Biological Model Revenue & Cost MR>0 MEY Total Cost Maximum Economic Rent open-access equilibrium (break-even point) Total Revenue E E* Figure II-2. Economic Model E (Static) Effort 27 o p e n -a c c e ss e q u ilib riu m e x p lo ita tio n of fis h e ry fo r th e re so u rce fis h e ry . U nder u n c o n tr o lle d ( u n r e g u l a t e d ) , th e f i s h i n g i n d u s t r y w i l l v e ry l i k e l y end up o p e r a t i n g a t t h i s l e v e l . F re e e n tr y ( e x it ) in to an d o u t o f t h e f i s h i n d u s t r y w i l l a p p a r e n tly o c c u r i f I n d u s tr y o p e r a t e s t o th e l e f t (rig h t) o f th e b re a k even p o in t. F ir m s i n t h e f i s h e r y i n d u s t r y w i l l b e f o r c e d t o o p e r a t e a t th e o p en a c c e s s e q u i lib r i u m ; i f th e y do n o t, any n e t s u r p l u s g a in e d by f i r m s o p e r a t i n g t o t h e l e f t o f t h i s e q u ilib riu m w i l l a t t r a c t o t h e r f ir m s t o e n t e r . At t h i s p o in t a l l t h e f ir m s w i l l end up a t th e o p e n - a o c e s s e q u i l i b r i u m ; t h e e q u i l i b r i u m w hich l e a d s t o b o th b i o l o g i c a l and eco n o m ic t r a g e d y . c h a r a c t e r i z e d by o v e r f i s h i n g , s u s ta in a b le y ie ld , th e The fo rm e r w i l l be d e o l i n e i n p o p u l a t i o n s t o c k a n d lo w e r la tte r in c re a s in g f a c to r ( e f f o r t ) u sed . by d e c r e a s e d r e t u r n s d e s p i t e t h e The f i s h i n g i n d u s t r y i s o p e r a t i n g a t t h e l e v e l o f p r o d u c t i o n i n w h ic h m a r g i n a l p r o d u c t (m a rg in a l re v e n u e ) t u r n s o u t t o be n e g a t iv e . w ill n o t in c re a s e T h is means t h a t an y a d d i t i o n a l f i s h i n g e f f o r t th e t o t a l c a to h , b u t w i l l d e o re a se i t in s te a d . MEY c a n be o b ta in e d and w i l l u s u a l l y r e q u i r e l e s s e f f o r t t h a n o p e n - a c c e s s e q u ilib riu m (E^ c o m p a re d w i t h Eg i n F ig u r e 1 1 - 2 ) . However, t h e r e a r e f o r o e s w h ic h d r i v e e f f o r t b a c k t o E^ a s lo n g a s t h e r e i s no change i n th e n a tu r e o f o p e n - a c c e s s r e s o u r c e s . The t o t a l re v e n u e c u rv e i s a l o c u s o f any p o i n t w hich r e p r e s e n t s a b io lo g io a l e q u ilib riu m s in c e a t th e e x i s t i n g le v e l o f e f f o r t, c a u g h t e q u a l s g r o w th . E co n o m ic e q u i l i b r i u m % i l l be o b ta in e d when th e t o t a l c o s t c u rv e i n t e r c e p t s t h e t o t a l r e v e n u e c u r v e . t h e r e w o u ld be no c h a n g e i n e i t h e r t h e f i s h e ffo rt. 1 9 7 7 ). T h is s i t u a t i o n i s fis h At t h i s p o in t s t o c k o r t h e am ount o f o a l l e d a b io n o m io e q u i l i b r i u m (A n d e rso n , 28 G o rd o n a l s o u t i l i z e s a m o d e l w h ich o l o s e l y r e s e m b le s one u s e d i n f ir m th e o r y t o d e te rm in e th e optim um u s e l e v e l o f i n p u t , n am ely f i s h i n g e ffo rt. I n m aking h i s p o in t G ordon u s e s a p r o d u c tio n f u n c t i o n a p p ro a c h i n w hich he assu m es l i n e a r f u n c t i o n a l r e l a t i o n s h i p s b e tw e e n a v e r a g e p ro d u c tio n ( p r o d u c t i o n - p e r - u n i t o f f i s h i n g e f f o r t ) and t h e q u a n t i t y o f f is h in g e f f o r t as c a n be s e e n i n F ig u r e I I - 3 . re p re s e n t, re s p e c tiv e ly , th e a v e ra g e p ro d u c tiv ity o f th e f is h in g e f f o r t . o th e r f a c t o r s u sed in amount o f f i s h i n g T he c u r v e s AP a n d MP p r o d u c t i v i t y an d m a r g i n a l The c o s t s o f f i s h i n g s u p p l i e s a n d p r o d u c t i o n a r e assu m ed t o b e u n a f f e c t e d by th e e ffo rt. T hus, m a rg in a l c o s t and a v e ra g e c o s t o f f i s h i n g e f f o r t a r e i d e n t i c a l and c o n s ta n t, c u r v e , HC and AC i n F ig u r e I I - 3 . show n a s t h e h o r i z o n t a l T h ese c o s t s a r e assum ed t o i n o l u d e a n o p p o r t u n i t y in c o m e f o r t h e f i s h e r m e n . T h e o p tim u m l e v e l o f f i s h i n g e f f o r t w i l l b e Ox w h ic h p r o v i d e s a m axim um e c o n o m i c y i e l d in d ic a te d by t h e s u s ta in e d y ie ld a re a apqc. (H EY ) He f u r t h e r d e p i c t s t h a t t h e maximum (M SY), a d v o c a t e d by t h e b i o l o g i s t , w i l l o c c u r w hen m a rg in a l p r o d u c t i v i t y o f f i s h i n g e f f o r t e q u a l s z e r o w ith a c o r r e s p o n d in g f i s h i n g e f f o r t Oz. O b v io u s ly , th e optim um e c o n o m io f i s h i n g e f f o r t i s l e s s th a n t h a t w h ich w ould p ro d u ce th e maximum s u s t a i n e d y i e l d . 29 AP,MP and Cost a c MP AP x 0 z F i s h i n g Effort Figure II-3. Gordon's Optirnum Level of Utilization of Fishing Resource S c h a e f e r ' s m o d e l, w h ich i s a l s o c a l l e d a u r p l u s - p r o d u c t i o n ( y i e l d ) m odel o r l o g i s t i c - t y p e m o d el, h a s b een u s e d w i d e l y a s o n e a p p r o a c h t o fis h e ry r e s o u r c e m a n a g e m e n t, e s p e c i a l l y o p tim a l e f f o r t and maximum s u s t a i n e d y ie ld . d ra w n fro m t h e b i o l o g i c a l n a t u r e o f f i s h in e s tim a tin g th e le v e l o f T h i s m o d el i s b a s ic a lly p o p u la tio n s u n d e r d i f f e r e n t h a r v e s t i n g e f f o r t s and tim e s i n whioh th e b io m ass c h a n g e s i n r e s p o n s e to th e h a r v e s t a s i l l u s t r a t e d i n F ig u r e I I - 4 . 30 Yield Carrying Capacity of the Environment max Bmax Time F i g u r e I I - 4 . The B i o l o g i c a l o f F i s h P o p u la t io n an d R esp o n se t o th e H a r v e s t O ver Tim e B ased o n L o g i s t i c M odel Bmax r e p r e s e n t s th e maximum b io m ass w hich i s th e c a r r y i n g c a p a c it y o f th e e n v iro n m e n t (u p p e r l i m i t ) . A f t e r t h e f i s h a r e h a r v e s te d a t tim e 1, th e b io m ass w i l l grow b ack to an e q u i lib r i u m l e v e l a lo n g an S sh a p e c u rv e w h ich i n d i c a t e s lo w s t o c k l e v e l s th a t a t t h e r a t e o f b io m a ss g ro w th i n c r e a s e s w ith s t o c k s i z e , t h e r a t e w i l l t h e n d e c r e a s e a s s to c k a p p ro a c h e s maximum b io m a s s. B ’ max* On th e o t h e r h an d , a t h ig h e r s to c k l e v e l when th e h a r v e s t i s s m a ll, su c h a s a t tim e 2 , th e r a t e o f b io m ass g ro w th i s a l s o s m a l le r . 3 and 4 , th e f i s h a r e e x p l o i t e d a t t h e l e v e l w h ic h g i v e s B etw een tim e s t h e maximum ra te o f b io m a s s r e g e n e r a t i o n , t h a t I s a t Bm ax/2 , w here maximum h a r v e s t I s reac h ed . T h is l e v e l o f e x p l o i t a t i o n I s c o m p a r a b le t o th e le v e l o f maximum s u s t a i n e d y i e l d on th e p r o d u c tio n f u n c t i o n a s shown I n F ig u r e s I I - 1 and I I - 2 . A f te r tim e 4 , b io m a s s r e g e n e r a t i o n th e f i s h can n o t keep have been o v er e x p lo ite d , pace a n y m o re w i t h p r e d a t i o n , w h ich o o u ld l e a d t o th e s t o c k d e p l e t i o n 1 9 8 2 ). th e r a t e an d of ( P itc h e r and H a rt, By u s i n g t h e i l l u s t r a t i o n i n F ig u r e I I - 5 below we s e e how th e s u r p l u s y i e l d m odel d e v e lo p e d . Surplus yield Stock replacement max 2 M ax. yield B Figure II-5. Surplus Yield Model B.j an d B2 a r e t h e b io m a s s o f f i s h p o p u l a t i o n s fro m tw o s u c c e s s iv e tim e p e r i o d s , 1 and 2 , b e f o r e an d a f t e r r e g e n e r a t i o n h a s ta k e n p l a c e . f o r ty - f iv e d e g re e lin e A sh o w s t h e r e p l a c e m e n t o f t h e b io m a ss b etw een 32 p e r io d s . A long t h i s l i n e t h e r e w i l l be no c h a n g e i n p o p u l a t i o n s t o c k . Any b i o m a s s p r o d u c e d a b o v e t h a t r e q u i r e d f o r e x a c t r e p l a c e m e n t i s c o n s id e r e d a s u r p l u s , an d t h e r e f o r e can be e x p l o i t e d . The f i s h e r y w i l l b e i n e q u i l i b r i u m w hen th e q u a n t i t y o f f i s h h a r v e s te d i s e x a c t l y e q u a l t o th e s u r p l u s p ro d u c e d a t p e r io d 2 o v e r p e r io d 1. w i l l b e no c h a n g e i n f i s h b io m a s s . C o n s e q u e n tly , t h e r e From t h i s b a s i c c o n c e p t, th e n a m a th e m a tic a l f u n c t i o n o f s u r p l u s y i e l d i s d e r i v e d w h ic h e x p r e s s e s t h e r e l a t i o n s h i p am ong t h e v a r i a b l e s i n f i s h i n g a c t i v i t i e s su c h a s : r a t e o f ch an g e o f b io m a s s , f i s h i n g e f f o r t , fis h in g r a te , th e o a tc h a b lllty and y i e l d i n o r d e r t o d e te r m in e th e l e v e l o f maximum e f f o r t and MSY ( s e e e q u a tio n 3 .5 )* P a u ly ( 1 9 7 9 ) m e n t i o n s t h a t S c h a e f e r * s m o d el c a n b e u s e d t o make y i e l d a s s e s s m e n t when a d a ta o n ly ). m in im u m o f d a ta i s a v a ila b le T h is m odel h a s b e en a p p lie d t o th ro u g h o u t t h e w o rld w ith v a r y i n g s u c c e s s . (c a to h and e f f o r t a n u m b er o f f i s h e r i e s P a u ly f o l l o w s t h r o u g h by p r e s e n t i n g a s s u m p tio n s made f o r d e r i v i n g S c h a e f e r 's m odel su o h a s : 1. F is h p o p u la tio n i n a f i n i t e e c o s y s te m g ro w s i n w e ig h t (w) u n t i l i t r e a c h e s th e maximum c a r r y i n g o a p a c ity ; t h e i n c r e a s e i n t o t a l w e i g h t c e a s e s when p o p u la tio n s to c k s r e a c h maximum b io m a ss (Bmax) . 2. Bmax c o r r e s p o n d s t o th e v i r g i n b io m a ss o f t h e s to c k . 3. T he g ro w th o f t h e f i s h b io m ass to w ard BIQcUC o v e r tim e c o u ld be d e s c r ib e d by a l o g i s t i c c u rv e w here f i r s t d e r i v a t i v e , d w /d t , h a s a maximum a t Bmax/ 2 80(1 z e r o v a l u e s a t BmaY and B = 0 . 4. T he p o p u l a t i o n s to c k a t *max/2 ( p o p u la t io n s to c k o f h a l f i t s o r i g i n a l s i z e ) w i l l g iv e th e h ig h e s t n e t g ro w th o f th e s t o c k , and p ro d u c e a maximum s u r p l u s y i e l d t o be h a r v e s te d . 33 5. If th e b io m a s s o f Bm a x / 2 , th e e x p lo ite d s to c k i s m a in ta in e d a t t h e n t h e maximum s u r p l u s y i e l d in d e fin ite ly . can be s u s ta in e d T h is i s e a l l e d maximum s u s t a i n e d y i e l d (M SY). S ee F ig u r e I I - 6 . Many s t u d i e s h a v e b e e n c o n d u c t e d i n s e v e r a l re g io n s u s in g th e S c h a e f e r m o d elf a s shown i n T a b le I I - 7 b elo w : T a b le I I - 1. The A p p lic a tio n o f S c h a e f e r Model A rea A u th o rs G eorges Bank (USA) Brown e t a l. (1 9 7 6 ) G u lf o f T h a ila n d M arr FAO e t a l. (1 9 7 6 ) (1 9 7 8 ) M alacca S t r a i t s In d o n e s ia n M a la y sia n W a te rs T h a i W aters S u ja s ta n i e t a l . (1 9 7 6 ) Lam Ah Wang & P a t h a n s a l i (1 9 7 7 ) SCSP (1 9 7 6 ) P h ilip p in e s V is a y a and Sam ar S eas S u k e, B ohol S e a s , Moro G u lf SCSP SCSP S o u rc e : (1976) (1 9 7 7 ) P a u ly , 1979. Many s t u d i e s w h ich m o d ifie d S c h a e f e r 's m odel h av e b e e n u se d an d a p p l ie d by many s c h o l a r s su c h a s F u llen b au m and B e l l (1 9 7 4 ), W a lte r s (1 9 7 8 ), and H ilb o rn ( 1979) . 2 T h e re a r e , m o d e l. h o w e v e r , som e c r i t i c i s m s o f S c h a e f e r 's s u r p lu s y i e l d R ic k e r s t a t e s t h a t i n th e S c h a e f e r m o d el, maximum y i e l d o r Y max a lw a y s o c c u r s a t Bmax/ 2 » th e th is is th a t i t i s p o s s ib le , th e p a ra b o la . A co n seq u en c e o f by r e a r r a n g i n g an d s o l v i n g a c o u p l e o f 2 F o r m o re d e t a i l a n d r i g o r o u s d i s c u s s i o n an d c o m p a r is o n o f d i f f e r e n t bio n o m io m o d els fro m G o rd o n , S c h a e f e r , T u r v e y , F u lle n b a u m , e t o . s e e i n G h an b ari (1 9 7 7 ). 34 A B icm ass G row th R a te max max dw dt Max Time Y ie ld MSY S u s t a i n a b l e Y ie ld C u rv e B max f= 0 B. max u n d e rfis h in g max B=0 o v e rfis h in g F ig u r e I I - 6 . T he S i n p l e S c h a e f e r 's M odel A. T he L o g i s t i c C u rv e o f P o p u la t io n G row th B. T he Y ie ld -B ic m a s s a n d Y i e l d - E f f o r t R e l a t i o n s h i p 35 s i m u l t a n e o u s e q u a t i o n s , t o e s t i m a t e MSY and maximum e f f o r t ( f 2Q8X ) from two o r more e q u i l i b r i u m y i e l d t a k e n i n p a s t y e a r s , w i t h o u t k n o w in g q ( c a t c h a b i l i t y r a t e ) o r t h e s to c k s i z e ( P i t c h e r and H a r t, 1 9 8 2 ). P i t c h e r and H a rt a l s o m e n tio n th e a d v a n ta g e s a n d d i s a d v a n t a g e s o f s u r p l u s y i e l d m o d e l. The a d v a n ta g e s a r e t h a t d a t a i s r e q u i r e d o n ly on o a tc h and e f f o r t , w hich i s e a s i e r t o g e t , MSY w i l l be e a s y t o c a l c u l a t e , and i t p r o v id e s p r a c t i c a l a d v a n ta g e . The d is a d v a n ta g e s a r e t h a t : t h e m o d e l i g n o r e s th e r e a l b i o l o g i c a l p r o c e s s w h ich a c t u a l l y g e n e r a te s th e b io m a s s, w here b io m ass i t s e l f i s a n i n t e r a c t i n g p r o c e s s o f g ro w th , r e c r u i tm e n t and m o r t a l i t y , th e m odel a ls o ig n o re s th e age s tru c tu re o f th e f is h p o p u la tio n w h ere d i f f e r e n c e s i n ag e s t r u c t u r e c a n a l t e r t h e g ro w th p r o c e s s d r a s t i c a l l y . E v en th o u g h th e S c h a e f e r model i s a r a t h e r s im p le way t o r e p r e s e n t t h e com plex d y n am ics o f t h e f i s h e r y , t h e e x t e n t o f i t s m an ag em en t i n use in fis h e ry t h e p a s t and i n th e f u t u r e i s e v id e n c e t h a t th e m odel i s o fte n re g a rd e d as an a p p ro x im a tio n o f th o s e c o m p le x d y n a m ic s . T h e r e f o r e , th e s u r p l u s y i e l d m odel s h o u ld be em ployed w ith g r e a t c a u t i o n i n f i s h e r y m an ag em en t. T he m o d e l, h o w e v e r , o n l y r e q u i r e s c a t c h an d e f f o r t d a t a w h ich i s l a r g e l y a v a i l a b l e ( U h le r , 1 9 8 0 ). A n o th er a p p ro a c h (m o d el) u s e d t o e s t i m a t e MSY i s w h a t i s " d y n a m ic p o o l" o r B e v e rto n and H o lt m o d e l. c a lle d a T h i s m o d e l i s m o re c o m p lic a te d a n d n e e d s a g r e a t d e a l m o re i n f o r m a t i o n t h a n c a t c h a n d e f f o r t f o r th e s u r p lu s y i e l d m o d el. I n dynam ic p o o l m o d e ls, one s h o u ld d e a l w ith p o p u la tio n p r o c e s s e s s u c h a s t i s s u e g r o w t h , m o r t a l i t y , and I n c r e a s e s i n t h e num ber o f f i s h th ro u g h r e p r o d u c t io n ( P i t c h e r and H a rt 1 9 8 2 ). J e n s e n (1 9 7 3 ) d e s c r i b e s t h e dynam ic p o o l m odel a s th e e s t i m a t i o n o f b io m a s s by s p e c i f y i n g f u n c t i o n s w i t h r e s p e c t t o a g e , f o r s i z e o f c o h o r t, i n d i v i d u a l w e ig h t, and a p p l i c a t i o n o f th e c o e f f i c i e n t o f f i s h e r y m o rta lity . I n th e s u r p lu s y i e l d m odel th e te rm s f o r r e c r u i tm e n t, g r o w th , an d n a t u r a l an d f i s h i n g m o r t a l i t y are a ll o o m b in e d i n th e e x p r e s s io n f o r a n n u a l b io m a ss a c c u m u la tio n . The n a t u r e o f th e s u p p ly o f f i s h e r y r e s o u r o e s i s som ew hat d i f f e r e n t t h a n t h e s u p p ly o f o t h e r p r o d u c ts w h ich g e n e r a l l y h av e p o s i t i v e s l o p e s . E v id e n c e from a few p r e v io u s s t u d i e s r e v e a l s t h a t f i s h e r y s u p p ly c u r v e s may h av e a backw ard s lo p e (C opes 1970; C r u t c h f i e l d and P o n te o o rv o , 1969; C la r k , 1 9 7 6 ). T h is i n d i c a t e s t h a t a f t e r c e r t a i n r a n g e f i s h s u p p ly h a s a n e g a tiv e s lo p e ( s e e F ig u re I I - 7 ) . The b ack w ard b e n d in g s u p p ly c u rv e o c c u r s a f t e r t h e f i s h i n g e f f o r t e x c e e d s th e l e v e l o f e f f o r t (Emay) t o m axim ize a s u s t a i n e d y i e l d . w ill ra is e A f t e r th e MSY p o i n t , an y i n c r e a s e i n demand p r i c e s a n d a t t r a o t m ore e n t r y i n t o th e i n d u s t r y w hich w i l l c a u s e o v e r f i s h i n g , and t h e r e f o r e , l i m i t o u tp u t ( y i e l d ) . T he r e d u c e d y i e l d w i l l be s h a r e d among an in c r e a s e d num ber o f f ir m s w h ich o p e r a t e i n th e n e g a t i v e l y s lo p e d p o r t i o n o f th e s u p p ly f u n c t i o n . An i n c r e a s e i n dem and fro m D1 t o D2 w i l l i n c r e a s e th e e f f o r t t o c a tc h th e same o r s m a l le r number o f f i s h . p ro d u c tio n m ig h t i n c r e a s e , In th e b e g in n in g , th e f i s h t e m p o r a r i l y , w i t h i n c r e a s i n g d em an d . H owever, a f t e r p a s s in g MSY, a n y e x p a n s i o n i n e f f o r t , to in c re a s e th e s u p p l y i n o r d e r t o m e e t th e dem and, w i l l le a d t o d e c r e a s i n g t h e amount o f y i e l d t o Yg. The f i s h e r y i n d u s t r y th e n i s o p e r a t i n g a t th e backw ard s l o p i n g s u p p ly c u r v e r a n g e . fis h in g e f f o r ts re d u c e e f f i c i e n c y Econom ic r e n t w i l l d i s s i p a t e an d e x c e s s i v e ( i n p u t s ) w i l l p r o b a b l y o c c u r w h ic h w i l l i n e f f e c t , a n d l e a d t o e c o n o m ic w a s t e . C la rk (1 9 7 6 ) a r g u e s 37 f u r th e r m o r e , t h a t a n i n c r e a s e i n demand u n d e r t h i s d e c r e a s e t h e am o u n t o f c o n s u m e r s u r p l u s . c o n d itio n a ls o w ill T h is i n d i c a t e s t h a t i n th e f i s h e r y i n d u s t r y , w here r e s o u r c e s a r e l i m i t e d by b i o l o g i c a l n a t u r e , in o re a s e an i n dem and m ig h t n o t n e c e s s a r i l y b e n e f i t th e f is h e r m e n due to in c re a s e s in f i s h p r ic e s . T h is s i t u a t i o n c a n be u n f o r t u n a t e f o r b o th consu m ers and p r o d u c e r s i n te rm s o f h ig h e r p r i c e s , lo w e r y i e l d s , and a l l p ro fits lo s t. MSY Y F ig u re II - 7 . l o n g - r u n F i s h e r y S u p p ly a n d Demand C u rv es When m ore p e o p le and f ir m s oom pete f o r a s t a b l e o r s h r i n k i n g s u p p ly o f t h e f i s h e r y , i t o b v io u s ly c r e a t e s more t e n s i o n an d m a k e s r e g u l a t i o n m ore d i f f i c u l t to e n fo rc e . govern m en t t o I n t e r v e n e re so u ro e . T h i s g e n e r a t e s c o n s t a n t p r e s s u r e f o r th e an d r e g u l a t e th e u t i l i z a t i o n o f th e f is h e r y M o reo v er, th e e x i s t i n g p ro b le m s h av e b e e n i n t e n s i f i e d by th e i n s t a b i l i t y o f th e f i s h e r y p r o d u c tio n and h ig h s e a s o n a l v a r i a t i o n s w hich 38 c a u s e i n s t a b i l i t y i n th e s u p p ly o f f i s h , th u s f lu c tu a tin g th e m a rk e t p ric e s . G h a n b a r i (1 9 7 7 ) c o n d u c te d a s tu d y o n demand an d s u p p ly , a s w e l l a s b io e co n o m ic a n a l y s i s o f U .S . G r e a t L a k e s w h i t e f i s h . e x te n s iv e ly t o e s t i m a t e demand and s u p p ly f u n c t i o n s . He u s e d m o d e ls Among th e m o d els u s e d a r e s im p le o r d in a r y l e a s t s q u a r e s (OLS) e q u a t i o n s , w ith d is trib u te d la g s , r e d u c e d fo rm e q u a t i o n s , OLS e q u a t i o n s an d tw o an d f o u r s im u lta n e o u s e q u a t io n s u s in g two an d t h r e e s t a g e l e a s t s q u a r e s . fro m h is s tu d y g iv e s R e s u lt s a g o o d e x p l a n a t i o n o f t h e dem and f u n c t i o n . G h a n b a ri o b ta in e d s t a t i s t i c a l l y s i g n i f i c a n t e s t i m a t e s by u s i n g e i t h e r OLS, r e d u o e d fo r m o r two s ta g e l e a s t s q u a r e (2SLS) te c h n iq u e s . e s tim a te s d id n o t m eet h i s n e g a tiv e ly e x p e c ta tio n s l o p e d s u p p ly c u r v e s . but ra th e r, S u p p ly g a v e m o s tly Only t h e e s t i m a t e s u s in g a sy ste m o f f o u r e q u a t io n s g av e a p o s i t i v e l y s l o p i n g s u p p ly e q u a t io n , a l t h o u g h m o st o f t h e v a r i a b l e s w ere n o t s i g n i f i c a n t a t th e 10 p e r c e n t l e v e l . From h i s s tu d y , G h an b ari h a s b een a b le t o e s t i m a t e t h e m a g n itu d e o f w h ite fis h e la s tic itie s b e tw e e n - 2 a n d c ro s s -p ric e -4 ; i n w h ic h p r i c e e l a s t i c i t y in o o m e e la s tic ity e la s tic ity .1 8 . o f dem and w as a b o u t 2 . 2 ; o f dem and w ith b e e f p r i c e was a b o u t 2 . 3 ; c r o s s e l a s t i c i t y w ith la k e t r o u t w as a b o u t 2 . 0 . w as . 2 5 . o f dem and r a n g e d C ro ss e l a s t i c i t y P ric e e l a s t i c i t y o f s u p p ly o f s u p p l y w i t h l a k e t r o u t p r i c e was a b o u t G h an b ari d i d n o t e x p e o t t o h a v e a n e g a t i v e s u p p l y c u r v e . H is f i n d i n g s h o w ev er, w ere n o t u n e x p e c te d b a se d o n p r e v io u s s t u d i e s by Copes (1 9 7 0 ) and C la rk (1 9 7 6 ). T h is m ig h t i n d i c a t e t h a t t h e f i s h i n g i n d u s t r y on th e G re a t L akes h a s o p e r a te d u n d e r a backw ard s lo p in g s u p p ly c u rv e a s a r e s u l t o f o v e r f i s h i n g , w hich p r o v id e s l e s s f i s h f o r c a t c h i n g . i s a n o th e r p o s s i b i l i t y T h e re w h ic h m ig h t e x p l a in t h i s s i t u a t i o n ; U .S . G re a t 39 L akes f i s h e r y r e g u l a t i o n h a s r e s t r i c t e d th e number o f f i s h t o b e c a u g h t an d c o m p e t i t i o n w i t h s p o r t f i s h i n g h a s l e f t o om m ereial fis h e rm e n w ith l e s s f i s h t o b e c a u g h t d e s p i t e th e i n c r e a s i n g p r i c e s . C o p es (1 9 7 0 ) c o n s id e r e d t h a t th e b ack w a rd -b e n d in g s u p p ly c u rv e was o f t e n r e p r e s e n t a t i v e o f t h e f i s h i n g i n d u s t r y , a f i n d i n g t h a t w as s i m i l a r t o G h a n b a r i's r e s u l t s . Dow e t a l . ( 1 9 7 5 ) c o n d u c t e d a s t u d y on M ain e l o b s t e r f i s h e r i e s w hich i n d i c a t e d t h a t th e e x p a n s io n o f demand f o r l o b s t e r w as a d r i v i n g fo rc e in t h e e x p a n s io n o f t h e f i s h i n g e f f o r t , i n te rm s o f t h e number o f tra p s used. From 1940 t o 1971 th e number o f t r a p s i n c r e a s e d a b o u t 5 . 6 p e r c e n t a n n u a l ly , an i n c r e a s e from 2 2 0 ,0 0 0 t o 1 .2 m i l l i o n t r a p s . a l . c o n c lu d e d t h a t M a in e l o b s t e r f i s h e r y w as o v e r c a p i t a l i z e d . Dow e t Any i n c r e a s e s i n t h e dem and f o r l o b s t e r s w o u ld r e s u l t i n d e c r e a s i n g th e q u a n t i t y s u p p lie d s in c e th e e s t i m a t e s i n d i o a t e d t h a t maximum s u s t a i n e d y ie ld c o u l d b e c a u g h t w ith a p p r o x im a te ly h a l f o f t h e e x i s t i n g t r a p s i n 1971. Dow e t a l . a l s o t r i e d t o m easu re th e im p a c t o f v a r i o u s management s tra te g ie s ( u s i n g a s i m u l a t i o n m o d e l) w h ic h c o u l d be im posed o n th e M aine l o b s t e r f i s h e r y th ro u g h r e g u l a t i o n s s u c h a s : 1. F r e e z i n g e x i s t i n g (1969) f i s h i n g e f f o r t by p l a c i n g a l i c e n s e fe e on tr a p s . 2. R ed u o in g t h e e x i s t i n g l e v e l o f f i s h i n g e f f o r t t o th e p o in t o f MSY by p la c in g a l i c e n s e f e e on t r a p s . 3. R ed u c in g t h e e x i s t i n g l e v e l o f f i s h i n g e f f o r t t o th e l e v e l o f m a rg in a l c o s t o f l a n d in g e q u a l t o e x - v e s s e l p r i c e (MC=MR), t o g e t maximum econom ic b e n e f i t . 40 4. Is s u in g a s to c k c e r t i f i c a t e t o e a o h v e s s e l ow ner b a se d on a v e ra g e c a tc h o v er th e l a s t 5 y e a rs w h ile e x is tin g l e v e l (1 9 6 9 ) o f f i s h i n g e f f o r t . fre e z in g th e T h is c e r t i f i c a t e c o u ld b e u s e d e i t h e r to c a to h f i s h o r t o s e l l f o r c a s h . 5. D oing n o th in g . From t h e s e 5 management p o li c y s t r a t e g i e s Dow p r o j e c t e d t h e im p act on v a r io u s a s p e o ts o f t h e l o b s t e r f i s h e r y s u c h a s : c a tc h , n u m b er o f v e s s e l s , p ric e s , l i c e n s e f e e s c o l l e c t e d by s t a t e , l i c e n s e f e e p e r v e s s e l and f is h e r m e n . One t h i n g t h a t Dow d id n o t e s tim a te tra p s , c a tc h , v a lu e o f w a s c o s t s I n c u r r e d t o im p o se t h o s e v a r i o u s r e g u l a t i o n s , e s p e c i a l l y f o r th e s t a t e . M a ra sc o (1 9 7 0 ) d is o u s s e d t h e m o d e ls u s e d by B e l l i n 1 9 69 t o e s ti m a t e t h e w o rld demand and s u p p ly o f t u n a o v e r t h e 1 9 7 0 -9 0 p e r i o d . B e l l in tr o d u c e d f o u r r e l a t i o n s h i p s i n th e demand and s u p p ly o f t u n a . - t h e p r o d u c e r s ' s u p p ly r e l a t i o n (raw tu n a ) - t h e p r o c e s s o r s ' demand r e l a t i o n (raw tu n a ) - t h e p r o c e s s o r s ' s u p p ly r e l a t i o n (o an n ed tu n a ) - t h e c o n s u m e rs ' demand r e l a t i o n (can n e d tu n a ) B e l l o n ly e s ti m a t e d th e c o n su m e rs' dem and p a r a m e t e r s a n d o m i t t e d t h e r e m a in d e r o f t h e demand and s u p p ly r e l a t i o n s h i p s . M arasco , u s in g a m odel em ployed by B e l l , e s t i m a t e d t h e dem and a n d s u p p l y o f ra w t u n a . L in e a r and l o g a r i t h m i c fo rm s w ere u s e d i n th e p r o c e s s and w ere e s tim a te d * by u s in g OLS m e th o d s . A c c o r d in g t o M a ra sc o s i m u l t a n e o u s e s t i m a t i o n p r o c e d u r e s w e re n o t r e q u ir e d due to th e f a c t t h a t p r i c e s p a id t o f i s h e r m e n a r e known p r i o r E v id e n tly , to d e p a rtu re fo r th e fis h in g g ro u n d . t h e c o e f f i c i e n t s o f s u p p l y e q u a t i o n s from th e s e e s t i m a t e s 41 l a c k s i g n i f i c a n c e a t 80 and 90 p e r c e n t p r o b a b i l i t y l e v e l s . M o re o v e r, th e s u p p ly e q u a t io n h a s a n e g a tiv e p r i c e c o e f f i c i e n t . A s tu d y c o n d u c te d by N ash i n 1969 o n dem and a n a l y s i s o f t h e S a n P e d r o w e t f l s h , w h ic h w as c a r r i e d o u t on s e v e r a l f i s h s p e c i e s , r e v e a le d t h a t p r i c e s d id n o t o h an g e v e r y much i n r e s p o n s e t o o h a n g e s i n l a n d i n g s . Demand w as p r i c e i n e l a s t i o . The q u a n t i t y o f f i s h la n d in g s d id n o t h av e a n y s t r o n g r e l a t i o n s h i p w i t h c o n s u m e r in c o m e e x c e p t s a rd in e s . T h is im p lie s t h a t a r i s e i n in c o m e i s fo r tu n a and n o t n e c e s s a r i l y an in c r e a s e i n t h e m a rk e t s i z e o f t h e s e f i s h s p e c i e s . C le a ry ( 1 9 6 9 ) i n h i s s tu d y t o p r o j e c t th e U .S . sh rim p c o n su m p tio n i n t o th e y e a r 2 0 0 0 , e s ti m a t e d and m e a su re d t h e f o r c e s d e t e r m i n i n g t h e l e v e l o f co n su m p tio n and t h e p r i o e l e v e l o f sh rim p i n t h e U n ite d S t a t e s . I n h i s e s t i m a t e , C le a ry u s e d l o g a r i t h m i c a n d a r i t h m e t i c f u n o t i o n s t o e s tim a te s h rim p c o n s u m p tio n . T h is r e s u lte d in a s t a t i s t i c a l l y s i g n i f i c a n t e s t i m a t i o n and a h ig h R2 , r e g a r d l e s s o f w h e th e r h e r e g r e s s e d t o t a l sh rim p c o n su m p tio n o r p e r c a p i t a s h r im p c o n s u m p t io n . He f o u n d t h a t w h i l e t h e dem and f o r s h rim p i s p r i c e i n e l a s t i c w ith t h e m a g n itu d e o f about - .6 0 to - . 6 5 , in c o m e e l a s t i c i t y f o r s h r im p w as a b o u t 1 . 7 0 . D e f l a t e d in c o m e p e r c a p i t a f o r i n s t a n c e w as a b l e t o a c c o u n t f o r 94 p e r c e n t o f th e v a r i a t i o n i n t o t a l c o n s u m p t io n , a n d 87 p e r c e n t o f t h e v a r i a b i l i t y i n p e r c a p i t a c o n su m p tio n . C a t o 's s tu d y (1 9 7 6 ) o f th e demand f o r F l o r i d a m u l le t i n d i c a t e d t h a t th e a n n u a l d o c k s id e p r i c e w as in f l u e n c e d by th e q u a n t i t y o f m u lle t and p e r s o n a l in c o m es, w here th e q u a n t i t y o f a l l o t h e r f i n f i s h la n d e d d id n o t seem im p o r ta n t i n in f l u e n c i n g m u lle t p r i c e s . H o w e v e r, t h e r e w as som e i n d i c a t i o n o f s e r i a l c o r r e la tio n in h is e s tim a te s . C ato a l s o e s tim a te d m o n th ly demand f u n c t i o n s u s in g a f i r s t d e g re e p o ly n o m ia l d i s t r i b u t e d l a g 42 m odel w ith 3 m onths l a g . He fo u n d t h a t t h e m o n th ly p r i o e o f m u l l e t w as n o t o n l y i n f l u e n c e d by t h e c u r r e n t m onth la n d in g s b u t a l s o by la n d in g s i n th e p r e c e d i n g m o n th . H o w e v e r, t h e q u a n t i t y o f m u l l e t l a n d e d i n p r e v i o u s m o n th s became l e s s im p o r ta n t i n i n f l u e n c i n g t h e p r i c e th a n th e c u r r e n t la n d in g . He a l s o e s t i m a t e d p r i c e f l e x i b i l i t i e s b ased on m o n t h ly , b i m o n t h l y , q u a r t e r l y and a n n u a l d a t a w ith m a g n itu d e s o f . 123; .1 2 9 ; .1 8 4 ; and 1 .2 5 1 , r e s p e c t i v e l y . fle x ib ility c o e ffic ie n t of p ric e f o r a n n u a l d a t a i s g r e a t e r th a n f o r q u a r t e r l y , q u a r t e r l y g r e a t e r th a n b im o n th ly and so f o r t h . becom e m o re f l e x i b l e lo n g e r. The A c c o r d in g t o T h ese f i g u r e s i n d i c a t e t h a t p r i c e s a s t h e t i m e p e r i o d f o r p r i c e a d ju s tm e n t becom es C a t o , t h i s i s m a in ly d u e t o th e co n su m e rs' r e s p o n s i v e n e s s t o c h a n g e i n q u a n t i t y o f m u l l e t l a n d i n g s a t a lo n g e r p e r io d s in c e s t o r a g e f o r m u l le t beyond t h r e e m o n th s i s l e s s l i k e l y . K u a te rn ik e t a l . ( 1 9 8 3 ) u s in g m o n th ly la n d in g s o f h a rd clam s from V i r g i n i a , New Y o rk , New J e r s e y , R hode I s l a n d , M a r y l a n d an d N o rth C a r o l i n a o v e r t h e p e r i o d 1 9 6 0 -1 9 8 3 , e s ti m a t e d t h e p r i c e f l e x i b i l i t y by t h e l e a s t s q u a r e s m e th o d . I t tu rn e d out th a t p ric e fle x ib ility c o e f f i c i e n t s w e r e v e r y s m a l l a n d o n l y a b o u t f o r t y tw o p e r c e n t o f t h e e x - v e s s e l p r i c e c h a n g e s w e r e e x p l a i n e d by t h e s u p p l y r e s p o n s e m o d e l used. 4 J o h n s o n ( 1 9 8 1 ) , i n h i s s tu d y on Lake M ich ig an ch u b s e s ti m a t e d t h e d o c k s id e demand f o r number one g r a d e c h u b s . (n e g a tiv e ) fo r p ric e He fo u n d th e e x p e c te d s i g n a n d c o n s u m p tio n r e l a t i o n s h i p s e x c e p t f o r th e p e r c a p i t a p e r s o n a l in c o m e w h ic h a l s o h a d a n e g a t i v e s i g n . The p r i c e f l e x i b i l i t y o f t h e e s ti m a t e d demand e q u a t io n w as a l s o v e r y s m a ll. S u d arso n o (1 9 7 9 ), who c o n d u c te d a s tu d y on e l a s t i c i t i e s and s u p p ly o f I n d o n e s ia n f i s h e r i e s , o f dem and e s t i m a t e d t h e demand and s u p p ly f u n c tio n s o f In d o n e s ia f r e s h f i s h c u l t i v a t e d in la n d w a te r f i s h , l i n e a r l o g a r i t h m i c e q u a t io n . (c o m p o s e d o f m a r i n e f r e s h fis h , a n d g e n e r a l in la n d w a te r f i s h ) u s in g a The q u a n t i t y o f f r e s h f i s h d em an d ed w as r e g r e s s e d o n p r i c e s o f m a rin e f r e s h f i s h , c u l t i v a t e d i n l a n d w a te r f i s h , I n la n d w a te r f i s h , s a l t e d f i s h , m eat an d on g r o s s n a t i o n a l p r o d u c t p e r c a p ita . T h is s tu d y r e v e a le d t h a t p e r c a p i t a incom e h a s a g r e a t e r im p act o n t h e q u a n t i t y o f f i s h d em an d ed , t h a n t h e im p a c t o f t h e m a r i n e f i s h p r i c e w h ic h i s t h e l a r g e s t p o r t i o n o f f i s h p r o d u c t i n I n d o n e s ia . e s t i m a t e s o f s u p p ly f u n c t i o n s f o r m a rin e f i s h , c u l t i v a t e d and in la n d w a te r f i s h re s u lte d in p o s itiv e in la n d w a te r s ig n s f o r a l l re g re s s io n c o e f f i c i e n t s , nam ely own p r i c e s an d t e c h n o lo g ie s ( i n fis h e rm e n b o a t r a t i o ) . H is te rm s o f la b o r o r M o re o v e r, f o r m a rin e and i n l a n d w a te r f i s h e s , th e r e s p o n s iv e n e s s o f q u a n t i t y s u p p lie d to w a rd te c h n o lo g y i s h ig h e r th a n to w ard p r i c e . CHAPTER I I I METHODS OF THE STUDY I n o r d e r t o a c h ie v e th e o b j e c t i v e s o f t h i s w i l l be in t r o d u c e d . s t u d y s e v e r a l m o d e ls T h is c h a p t e r w i l l d i s c u s s i n d e t a i l th e m eth o d s and m odels u s e d t o e s t i m a t e b io eco n o m io f a c t o r s and p r o d u c t i v i t y ; demand and s u p p ly ; p r i c e and incom e e l a s t i c i t i e s ; p r i c e f l e x i b i l i t y ; and consum er, p ro d u o q r and s o c i a l s u r p l u s o f M ic h ig a n G re a t L akes c o m m e rc ia l fis h e rie s . The B ioeconom io Model T h is m odel w ill e x p la in th e b e h a v io ra l in t e r r e la tio n s h ip s o f f is h e r y re s o u rc e s such a s f i s h i n g fa c to rs e ffo rt, and c a tc h , p o p u la tio n b io m a s s , e a r n i n g and c o s t fro m f i s h i n g . I n t h e m o d e l, a s e r i e s o f m a t h e m a t i c a l r e l a t i o n s h i p s w h ic h a p p r o x i m a t e t h e s t r u c t u r a l b e h a v i o r o f t h e f i s h e r y r e s o u r c e from th e r e a l w o rld a r e i n t r o d u c e d . to e s tim a te th e e q u ilib riu m l e v e l. - le v e l The b io eco n o m io model i n t h i s s tu d y a tte m p ts of c o m m e rc ia l fis h e ry u tiliz a tio n a t th e The e s t i m a t e s w i l l i n c lu d e : t h e l e v e l o f maximum s u s t a i n e d y i e l d (MSY) from s e v e r a l f i s h s p e c ie s . - t h e l e v e l o f h a r v e s t i n g w h ic h p ro d u c e s maximum econom ic y i e l d (MEY). 44 - t h e l e v e l o f e f f o r t a s s o c i a t e d w ith MSY and MEY. - th e p o p u la tio n g ro w th ra te c o e ffic ie n t, c a tc h a b ility c o e f f i c i e n t s , an d e n v iro n m e n ta l c a r r y i n g c a p a c i t y f o r e a c h f i s h s p e c ie s . T he l o g i s t i c s u r p l u s y i e l d te c h n iq u e w h ich w as d e v e lo p e d from t h e l o g i s t i c g ro w th model i s u s e d . ( 3 .1 ) and ( 3 .2 ) k (B) = k (1 - B/K) w h ere: B s p o p u la tio n s i z e (b io m a s s) k = i n t r i n s i c g ro w th r a t e ( p o p u la t io n g ro w th r a t e ) K = e n v iro n m e n ta l c a r r y i n g o a p a o ity t = tim e g ro w th i n b io m a ss i n th e a b se n c e o f f i s h i n g E q u a tio n ( 3 .1 ) g ro w s e x p o n e n t i a l l y , sh o w s t h a t t h e r a t e o f p o p u l a t i o n g r o w th , w hich o a n n o t p ro c e e d i n d e f i n i t e l y . E n v iro n m e n ta l l i m i t a t i o n s i n te rm s o f c a r r y i n g c a p a c i t y w i l l f o r c e th e g ro w th r a t e t o d e c lin e . S u b s t i t u t i o n o f ( 3 .2 ) t o ( 3 .1 ) w i l l g iv e : = kB (1 - B/K) ( 3 .3 ) E q u a tio n ( 3 .3 ) i s c a l l e d a l o g i s t i c e q u a t io n The h a r v e s t e q u a t io n i s shown i n e q u a tio n (3 * 4 ) Y 2 qEB ( 3 .4 ) 46 w h e re : Y s f is h y ie ld q = c a te h a b ility r a te (c o e ffic ie n t) E = fis h in g e f f o r t By i n t r o d u c i n g a h a r v e s t e q u a t i o n i n t o t h e m o d e l, th e l o g i s t i c s u r p l u s y i e l d m odel c o u ld b e w r i t t e n a s : = kB (1 -B /K ) - qEB ( 3 .5 ) or -*5- = kB - (k /K ) B2 - qEB at E q u a tio n ( 3 .5 ) i s eq u al to sh o w s t h a t th e ch an g e i n f i s h p o p u la tio n (b io m a ss) t h e d i f f e r e n c e b e tw e e n t h e a n n u a l r a t e o f in c re a s e of p o p u la tio n s i z e and t h e h a r v e s t . S u rp lu s p r o d u c tio n i s t h e am o u n t o f b io m ass p ro d u ced t h a t c a n be ta k e n o u t ( h a r v e s te d ) w ith o u t o h an g in g th e s t o c k s i z e . In o th e r w o rd s, a t t h e e q u i l i b r i u m s t a t e , t h e a n n u a l g ro w th o f f i s h b io m ass i s e q u a l t o t h e amount o f f i s h h a r v e s te d . T h e re fo re , a t th e th e s te a d y s t a t e , d B /d t = 0; t h u s , e q u a tio n ( 3 .5 ) kB (1 - B/K) = qEB = Y e q u ilib riu m y ie ld in w i l l g iv e : (3. 6) or Y = kB - _k_B2 • K ( 3 .7 ) E q u a t i o n ( 3 .7 ) g iv e s t h e e q u ilib r iu m y i e l d t h a t w i l l o o c u r a t eaoh bio m ass l e v e l . F a c t o r i n g o u t B from e q u a t io n ( 3 . 5 ) , and th e n s u b s t i t u t i n g i t i n t o e q u a tio n ( 3 . 7 ) , r e s u l t s i n e q u a tio n (3 * 8 ). 47 Y = qKE - _K_q2 E2 k ( 3 .8 ) By d i f f e r e n t i a t i n g e q u a t io n ( 3 . 7 ) , w ith r e s p e c t t o B, and e q u a tin g it to z e ro , th e p o p u la tio n s iz e a t w h ic h th e MSY o c c u r s w i l l be o b ta in e d : dY dB = k - 2k B = 0 K ( 3 .9 ) R e a rra n g e d e q . ( 3 * 9 ) , g iv e s u s : B* =_kK_ =_K_ 2k 2 ( 3 .1 0 ) w h ere: B* = b io m a ss a t maximum s u s t a i n e d y i e l d . E q u a tio n ( 3 .1 0 ) shows t h a t t h e b io m ass ( p o p u la t io n s i z e ) a t MSY i s e q u a l t o h a l f o f th e maximum b io m ass s to c k . S u b s t i t u t i n g ( 3 .1 0 ) i n t o ( 3 . 7 ) : Y* * k J L “ J L J L 2 2 K 2 = kK 2 - kK2 4K Y* s_kK_ 4 ( 3 .1 1 ) w h e re : Y* a f i s h h a r v e s te d a t maximum s u s t a i n e d y i e l d . E q u a tio n ( 3 .1 1 ) i s a MSY e q u a t io n . Maximum f i s h i n g e f f o r t (E *) a t MSY i s : * Y* a qEB E a Y* qB kK a_4 qK 2 a 2kK 4qK 48 E* =_k 2q ( 3 .1 2 ) The s u r p l u s p r o d u c tio n m odel c a n a l s o b e a p p l ie d f o r e s t i m a t i n g th e b io m ass o f th e s to c k w h ich was. d e r iv e d from e q u a tio n (3 * 4 ): B = Y/qE ( 3 .1 3 ) E q u a tio n ( 3 .1 3 ) shows t h a t th e b io m ass i n a c e r t a i n y e a r ( t i m e ) i s eq u al to y ie ld a t c e rta in ti m e d iv id e d by t h e p r o d u c t o f c a t o h a b i l i t y r a t e and f i s h i n g e f f o r t . T he e c o n o m ic m odel ( v a r i a b l e s ) s h o u ld be in t r o d u c e d i n t o th e b i o l o g i c a l m odel t o d e te r m in e t h e maximum e c o n o m ic y i e l d (MEY). T h is r e s u l t s i n a l e v e l o f f i s h h a r v e s t t h a t w i l l y i e l d maximum econom ic r e n t (p ro fit). I n t h i s c a s e c o s t i s assum ed t o b e i n p r o p o r t i o n t o e ffo rt, th e n : TC = ( 3 .1 4 ) w h e re : TC = t o t a l c o s t ( v a r i a b l e + f ix e d c o s t ) Cf s c o s t p e r u n i t o f e f f o r t E = e ffo rt T o ta l re v e n u e (TR ) o r t o t a l v a l u e p r o d u c t (TVP) e a r n i n g s fro m f i s h i n g i s e q u a l t o th e number o f f i s h s o ld a t a c e r t a i n p r i c e ( P ) . The re v e n u e e q u a tio n i s : TR = TVP = PY = P qEB ( 3 .1 5 ) w here Y i s th e y i e l d , w h ich i s e q u a l t o qEB ( S e e e q . 3 . 4 ) , w h ic h is a ls o c a lle d p ro d u c e rs' s u rp lu s , (L ) c a n b e d e r i v e d fro m t h e d i f f e r e n c e s b etw een t o t e d re v e n u e and t o t a l c o s t . L = TR - TC p ro fit ( 3 .1 6 ) 49 P r o f i t m a x im iz a tio n i s t h e o b j e c t i v e o f t h e b io e c o n o m io m o d el, s u b j e c t t o th e b i o l o g i c a l c o n s t r a i n t s from e q u a t io n (3 * 5 ). T he L a g r a n g ia n m u l t i p l i e r te c h n iq u e i s em ployed t o m axim ize p r o f i t (L ), L = PqEB w here +X (kB - k B2/K - qEB) X i s th e shadow p r i c e o f t h e c o n s t r a i n t , ( 3 .1 7 ) th a t is th e change in p r o f i t when th e c o n s t r a i n t c h a n g e s by one u n i t . By d i f f e r e n t i a t i n g e q u a tio n (3 -1 7 ) w ith r e s p e c t t o B, E a n d L ; s e t t i n g a l l th e s e e q u a t io n s e q u a l t o z e r o , and t h e v a l u e s o f B, E and L c a n be s o lv e d . dL dB = PqE +X (k - 2kB K - qE) = 0 ( 3 .1 8 ) dL dE = PqB - c f _ A qB =0 ( 3 .1 9 ) dL dX = kB - kB2 - qEB K =0 ( 3 .2 0 ) By s o l v i n g e q u a t i o n s ( 3 .1 8 ) ; (3 * 1 9 ); and ( 3 .2 0 ) s im u lta n e o u s ly , we g e t: B® = K + Cf 2 2qP ( 3 .2 1 ) E® = _k_ (1 - CP) 2q qPK ( 3 .2 2 ) = p - Cf qB® ( 3 .2 3 ) w h ere B® i s th e b io m ass a t MEY, and E® i s e f f o r t a t MEY. By s u b s t i t u t i n g B® and E® i n t o e q u a tio n ( 3 . 4 ) , th e MEY l e v e l w i l l be o b ta in e d . MEY = qE®B® = kB® -J c _ (B ® )2 K ( 3 .2 4 ) 50 By c o m p a r in g e q u a t i o n ( 3 .2 1 ) w ith ( 3 . 1 0 ) , and e q u a t io n (3 * 2 2 ) w ith ( 3 .1 2 ) , i t c a n be c o n c lu d e d t h a t : - th e b io m a ss a t KEY i s g r e a t e r th a n a t MSY, o r Be > B* - e f f o r t a t MEY i s s m a lle r th a n a t MSY, o r Ee < E* - y i e l d a t MEY i s s m a l le r th a n a t MSY L in e a r iz e d S u r p lu s P r o d u c tio n Method As m e n tio n e d b y J e n s e n d iffic u lt w hen o n ly ( 1 9 7 6 ) t h e e s t i m a t e s o f k , K an d q a r e o a tc h and e f f o r t d a ta a re used, th e re fo re , l i n e a r i z a t i o n o f th e s u r p l u s p r o d u c tio n m odel s h o u ld be e x p lo r e d . M o d ify in g e q u a tio n ( 3 .4 ) Y = qEB t o be Bt = J _ C V Et> a ( 1 /q ) ( 0 t> Q ( 3 *25) w h ere: = y ie ld per u n it o f e f f o r t in y e a r t ; s annual y ie ld in y e a r t ; q s th e c a t c h a b i l i t y c o e f f i c i e n t . T he d e r i v a t i v e o f e q u a t i o n p o i n t f o rm u la . = v d t 't ( 3 . 5 ) c a n b e a p p ro x im a te d w ith a two T h is w i l l g iv e Bt + 1 - Bt - 1 ------------- 2------------- ( 3 .2 6 ) S u b s t i t u t i o n ( 3 .2 6 ) i n t o ( 3 .2 5 ) w i l l r e s u l t : (_dB_) = _ L (A U .) dt t q w h ere: AUt = Ut + 1 - Ut - 1 2 ( 3 .2 7 ) 51 T hen, s u b s t i t u t i n g e q u a t i o n ( 3 .2 5 ) and ( 3 .2 7 ) i n t o e q u a tio n (3*5) g iv e s : /dBx = k ( 1 /q ) (Dt ) - k0<-2 - q (Yt / q ) ^ 2k W t a Ut S k o t - k ( D t) 2 - q l t ~W ( 3 .2 8 ) ( 3 .2 9 ) E q u a tio n ( 3 .2 9 ) c a n th e n be w r i t t e n i n te rm s o f a l i n e a r r e g r e s s i o n e q u a tio n : \ = a-jX, + a 2 X2 + a 3 Y3 ( 3 .3 0 ) w here zt X1 X2 X3 a1 = = °t °t = ° t2 s *t k 4 - a2 - a3 = -q k qK The c o n s ta n ts a ^ , a2 and a3 can be estim ated by le a s t squares, so the param eters o f M, K, and q can also be solved. 52 Demand and Supply Model To a n a l y z e t h e dem and (D) a n d s u p p ly (S ) o f s e v e r a l f i s h s p e c i e s (w h ite fis h , ch u b , y e llo w p erch , c a tfis h , and a l l e w i f e ) , se v e ra l r e g r e s s i o n m o d els w i l l be u s e d . S in g le - E q u a tio n Method D and S w i l l be e s ti m a t e d by u s in g th e s i n g l e e q u a tio n m o d e l w h e re p r i c e s a n d q u a n t i t i e s a r e assu m ed t o b e d e te rm in e d i n s e q u e n c e . T h is model i s e m p i r i c a l l y r e l e v a n t when tim e l a g s b e tw e e n v a r i a b l e c h a n g e s a r e l o n g o r w hen t h e ti m e o v e r w h ic h v a r i a b l e s a r e o b s e rv e d i s s h o r t (Tomek & R o b in so n , 1977)* The g e n e r a l fo rm s o f D and S e q u a t io n s a r e : Demand: Q = a - bPQ + CPS + dY ( 3 .3 1 ) S u p p ly : Q = a + bPQ - cPs - dPx ( 3 .3 2 ) w h e re : Q s q u a n tity PQ s p r i c e o f o u tp u t Pg s p r i c e o f s u b s titu te Y = incom e X = p r i c e o f in p u t a, b, c a n d d a r e p a r a m e t e r s w h ic h i n d i c a t e how t h e v a r i a b l e s a r e re la te d . 53 T h ro u g h a s i n g l e e q u a tio n m o d e l, s u p p ly f u n c t i o n s can b e e s tim a te d b a s e d on th e a ss u m p tio n t h a t when t h e demand c u rv e s h i f t s o v e r ti m e a n d t h e s u p p ly c u rv e re m a in s s t a b l e , th e s u p p ly c u rv e c a n be i d e n t i f i e d . If th e s u p p ly c u rv e s h i f t s o v e r tim e , and th e demand c u rv e r e m a in s s t a b l e , t h e demand c u rv e i s i d e n t i f i e d a s lo n g a s th e s h i f t i n th e two f u n c t i o n s a r e n o t h ig h ly c o rre la te d (T o m e k a n d R o b in s o n , 1 9 8 1 ). In th is s i t u a t i o n , e i t h e r p r i c e c a n d e te r m in e q u a n t i t y o r q u a n t i t y c a n d e te rm in e p ric e . T h e r e i s a l s o a p o s s i b i l i t y t h a t th e o u r r e n t p r o d u o tio n o f f i s h i s a f u n c t i o n o f th e p r e v io u s y e a r 's p r i c e . o f fis h m a r k e te d i n T h is assu m es t h a t t h e q u a n t i t y th e o u r re n t y e a r i s l a r g e l y p re d e te rm in e d by th e p r e v io u s y e a r 's p r i c e . Qt * f (P t-1 > ( 3 *33) w h ere: Qt = o u tp u t a t y e a r t P t-1 * p r i c e a t y e a r t - 1 ( p r e v io u s y e a r ) T h e r e f o r e , i t i s J u s t i f i b l e t o u s e a d i s t r i b u t e d l a g m o d el i n t h e a n a ly s is . d is trib u te d S im p le o r d i n a r y l e a s t s q u a r e s (OLS) te c h n iq u e , and OLS w ith la g w i l l b e u se d in a n a ly z in g D and S f o r th e s in g le e q u a tio n m o d e l. S im u lta n e o u s - E q u a tio n Method * I n a s i t u a t i o n w here p r i o e d o e s n o t d e t e r m i n e q u a n t i t y n o r d o e s q u a n tity d e te rm in e p ric e , s im u lta n e o u s ly d e t e r m i n e d but (J o in tly ra th e r p ric e and q u a n tity d e te rm in e d ) w ith in th e p e r io d , th e n a s im u lta n e o u s e q u a t io n m odel s h o u ld be u s e d . a re sam e tim e 54 I d e n t i f i c a t i o n o f t h e E q u a tio n I n s i m u l t a n e o u s - e q u a t i o n m o d e ls th e i d e n t i f i c a t i o n p ro b lem i s v e ry im p o r ta n t and w i l l be th o r o u g h ly c o n s id e r e d (Tomek and R o b in s o n , 1 9 8 1 ) . T h is m odel i s c o n c e rn e d w ith w h e th e r o r n o t e s ti m a t e s o f s t r u c t u r a l p a ra m e te r s c a n be o b t a i n e d , an d th e n w hioh te o h n iq u e i s m ore a p p r o p r i a t e to use i n th e e s tim a tio n . T h e re a r e t h r e e c a t e g o r i e s o f i d e n t i f i c a t i o n : 1. under id e n tifie d , u n id e n tifie d , a s i t u a t i o n i n w h ic h t h e e q u a t i o n i s and any e s tim a te o f s t r u c t u r a l p a ra m e te r c o e f f i c ie n t s i s u n a v a ila b le . 2. Ju st id e n tifie d , a s i t u a t i o n i n w h ich u n iq u e e s t i m a t e s a r e o b ta in e d f o r e a c h s t r u c t u r a l c o e f f i c i e n t . 3. over id e n tifie d , a s i t u a t i o n w ith m u ltip le e s tim a t e s o f c o e f f i c i e n t s ( n o t u n iq u e ) . To d e t e r m i n e i n w h ic h c a t e g o r i e s th e e q u a tio n u n d e r c o n s i d e r a t i o n w i l l be in c lu d e d , t h e f o llo w in g fo rm u la s c a n be u se d ( F o o te , 1 9 5 8 ). J u s t i d e n t i f i e d e q u a t io n s w i l l be o b ta in e d i f : S - N s E - 1 U nder I d e n t i f i e d e q u a t i o n s i f : S - N < E - 1 Over i d e n t i f i e d e q u a t i o n s i f : S - N > E - 1 w h e re : S = number o f v a r i a b l e s i n th e sy stem N = number o f v a r i a b l e s i n e a c h e q u a tio n E = number o f en d o g en o u s v a r i a b l e s i n th e sy stem 55 T h is fo rm u la c a n be a p p l i e d t o e a c h e q u a t io n i n th e s y ste m f o r c h e c k i n g w h e th e r t h e e q u a t i o n s a r e j u s t i d e n t i f i e d , id e n tifie d . o v e r id e n tif ie d o r under The v a r i a b l e s i n th e s y ste m e q u a tio n a r e oom p o sed b o t h o f e x o g e n o u s ( p r e d e te r m in e d ) v a r i a b l e s , whose v a l u e s a r e n o t d e te r m in e d i n th e sy ste m , and en d o g en o u s v a r i a b l e s w hose v a l u e s a r e d e te r m in e d i n t h e s y s te m . I f th e e q u a tio n i s ju s t id e n tifie d , th e n re d u c e d -fo rm o r i n d i r e c t l e a s t s q u a r e s (IL S ) m e th o d s m ig h t b e u s e d i n e s t i m a t i n g t h e s t r u c t u r a l p a r a m e te r c o e f f i c i e n t s o f demand and s u p p ly e q u a t io n s . Reduced Form For jo i n tly d e t e r m i n e d v a r i a b l e s i n s im u lta n e o u s e q u a t io n s , i t i s c o n c e iv a b le t h a t t h e r e i s a c o r r e l a t i o n b e tw e e n e x p l a n a t o r y v a r i a b l e s an d t h e e r r o r t e r m . e s ti m a t e th e m o d el. C o n s e q u e n t l y , th e OLS w i l l n o t be a p p r o p r i a t e t o By tr a n s f o r m in g th e s t r u c t u r a l e q u a tio n s (3 * 3 4 ) and (3*35 ) i n t o re d u c e d fo rm , eac h e q u a t io n w i l l c o n t a in o n ly one endogenous v a r i a b l e (P and Q a r e en d o g en o u s v a r i a b l e s ) , e l i m i n a t i n g t h i s p ro b lem . D: Q = a 1 + b ,P + CjY + e j ( 3 .3 4 ) S: P = a g + b 2Q + CgX + e 2 ( 3 .3 5 ) S u b s t i t u t i n g P from e q . (3 * 3 5 ) i n t o Q i n e q . ( 3 .3 4 ) an d s u b s t i t u t i n g i n t o P, th e n re d u c e d fo rm e q u a t io n s w i l l be o b ta in e d : Q = P = a 1 + b l a2 1 - b-|b2 + a 2 + b 2a 1 1 - b-]b2 + b ic 2 X + 1 - t>ib2 °2 1 - b ib 2 V + ci V + 1 - b ib 2 b 2°1 y + 1 - b ib 2 Q . ® 1+JL i® 2 1 - b-|b2 e 2 * b 2e 1 1 - b-|b2 (3*36) (3*37) 56 E q u a tio n s ( 3 .3 6 ) and ( 3 .3 7 ) c a n b e e s tim a te d by u s in g OLS, and t h e r e s u lt w ill be: Q = P1- S u X + " 12 Y + W1 ( 3 .3 8 ) P = 92 + * 21 x + ^ 2 2 y + W2 ( 3 .3 9 ) T hen, th e o r i g i n a l c o e f f i c i e n t s o f s t r u c t u r a l e q u a tio n s ( 3 * 3 4 ) an d (3*35 ) oan be s o lv e d by t h e f o llo w in g s t e p s : TTi ] bl = TTl z *12 e1 = *12 02 = ir12 a^ s 0.| - b^ 02 a2 = 02 (1 - b 1b 2 ) (1 - b.jbg) - b2 0 <| I n t h e new e q u a t i o n s ( r e d u c e d form e q u a t io n s (3*36) and ( 3 .3 7 ) )* t h e r e w i l l be no c o r r e l a t i o n b e tw e e n new e x p l a n a t o r y v a r i a b l e s w i t h e r r o r te rm s . T he r e d u c e d - f o r m e q u a t i o n s w i l l be e s ti m a t e d by OLS, and t h e n th e e s t i m a t e s o f th e s t r u c t u r a l p a ra m e te rs c a l c u l a t e d by u s in g th e e s t i m a t e s from re d u c e d -fo rm p a r a m e te r s . In d ire c t Least Square (ILSl I n t h i s m e th o d , t h e OLS e s t i m a t e s o f t h e re d u c e d form p a ra m e te rs a r e p lu g g e d i n t o e s t i m a t e t h e v a r i a b l e from a s t r u c t u r a l e q u a t io n . ( 3 .4 0 ) 57 (3 . 41) The e s ti m a t e d v a lu e s o f Q and P a r e th e n s u b s t i t u t e d i n t o th e s t r u c t u r a l e q u a tio n , a s in d e p e n d e n t v a r i a b l e s , s tru o tu ra l p a ra m e te r t o p ro d u c e th e e s tim a te s o f th e c o e ffic ie n ts . The s tru c tu ra l p a ra m e te r c o e f f i c i e n t s c a n th e n b e e s tim a te d a s shown i n th e e q u a tio n s b e lo w : Demand: Q a A1 + b., P + C, Y ( 3 .4 2 ) S u p p ly : P = Ag + b 2 Q + C2 X ( 3 .4 3 ) T w o-S tage L e a s t S q u a re ( 2SLS1 and T h r e e - S ta g e L e a s t S q u a re (3SLS) w ith Two and F o u r E q u a tio n s V hen we p u t m o re v a r i a b l e s e q u a t io n s may be o v e r i d e n t i f i e d . ( I n f o r m a tio n ) i n t o th e s y ste m , th e E s t i m a t i o n t h r o u g h IL S w i l l g i v e m u l t i p l e s o l u t i o n s (n o n -u n iq u e s o l u t i o n s ) . T h e r e f o r e , th e 2SLS o r 3SLS te c h n iq u e w i l l b e a p p r o p r i a t e f o r e s t i m a t i n g th e p a ra m e te rs w ith two and f o u r s im u lta n e o u s e q u a t io n s y s te m s . The 2SLS i s one way o f w e ig h in g t h e m u ltip le s o lu tio n . F o r 2SLS, f i r s t , re d u c e d form e q u a t io n s a r e e s tim a te d by r e g r e s s i n g end o g en o u s v a r i a b l e s on a l l p re d e te rm in e d (e x o g e n o u s ) v a r i a b l e s i n t h e s y s te m b y OLS a s show n i n e q u a tio n s (3 * 3 8 ) and ( 3 .3 9 ) . T hese I n s tr u m e n t a l v a r i a b l e s , c r e a t e d th ro u g h re d u c e d fo rm , w i l l n o t h a v e a n y c o r r e l a t i o n w ith th e e r r o r te rm , ev en th o u g h i n th e o r i g i n a l s t r u c t u r a l e q u a tio n t h e r e m ig h t be a c o r r e l a t i o n b etw een some e x p la n a to r y v a r i a b l e s and t h e e r r o r te rm . 58 I n t h e s e c o n d s t a g e , th e e s ti m a t e d v a lu e from t h e re d u c e d form a t s ta g e o n e, e q u a tio n s ( 3 . 3 8 ) a n d ( 3 .3 9 ) > can be u se d to e s tim a te th e p a r a m e t e r s o f t h e s t r u c t u r a l e q u a t i o n s , a g a in by u s in g OLS te c h n iq u e . So e q u a t io n s ( 3 .3 4 ) and ( 3 .3 5 ) w i l l be e s ti m a t e d a s f o ll o w s : Q = a1 + b ^ + c1 Y + e, ( 3 .4 5 ) P = *2 + bgQ + e 2 X + e 2 ( 3 .4 6 ) S in c e : Q A A *Q + W1 o r a a P = P + W 2 A A Q = Q - W1 A A P = P - w2 Then, s u b s t i t u t i n g i n t o e q u a tio n s ( 3 .4 5 ) and ( 3 .4 6 ) g i v e s : Q = a , - b-jP + 0 ^ + (e 1 + b ^ g ) ( 3 .4 7 ) P 8 a 2 + b2 Q + OgX + ( e 2 - bgW,) ( 3 .4 8 ) a a w here W1 and W2 a r e th e e s ti m a t e d r e s i d u a l fro m th e re d u c e d fo rm . T h r e e - S t a g e L e a s t S q u a re s in v o l v e s t h e a p p l i c a t i o n o f g e n e r a liz e d l e a s t s q u a r e e s t i m a t e s t o th e s y ste m o f e q u a t io n s w h ic h h a s f i r s t b e e n e s tim a te d by 2S L S . F ro m th e 2S L S p a r a m e t e r s , w h ic h h av e b e e n c a l c u l a t e d , th e r e s i d u a l s o f e a c h e q u a t i o n a r e u s e d t o e s tim a te th e c r o s s e q u a tio n v a r i a n c e s and o o v a r ia n c e s . Data and Inform ation Osed in t h is Study T he p r i c e p e r pound f o r eaoh f i s h s p e c i e s i n t h i s s tu d y i s a r r i v e d a t by d iv i d i n g th e t o t a l number o f la n d in g p ounds by t h e t o t a l n o m in a l v a lu e in d o lla rs . e x - v e s s e l v a lu e T he p r i c e p e r pound o f f i s h (d o c k s id e v a lu e ) s in c e th e d a ta r e f l e c t s th e tr u e s u p p lie d b y MDNR ( M i c h i g a n D e p a r tm e n t o f N a t u r a l R e s o u r c e s ) a r e b a s e d o n t h e to ta l 59 la n d in g s and la n d in g v a l u e s r e p o r t e d by t h e f is h e r m e n . S im ila rly , d a ta f o r e f f o r t fro m d i f f e r e n t t y p e s o f g e a r u s e d a n d t h e number o f f i s h c a u g h t by eac h ty p e o f g e a r i s b a s e d on th e in f o r m a tio n p r o v id e d b y t h e f is h e rm e n . One ty p e o f g e a r i s s e l e c t e d a s a s ta n d a r d g e a r and u s e d i n t h i s s tu d y t o m e a s u re c a t o h - p e r - u n i t o f e f f o r t (C P E ). T h i s w i l l be a c c o m p li s h e d by d i v i d i n g th e number o f f i s h c a u g h t (w ith s t a n d a r d g e a r ) by th e amount o f e f f o r t (m easu red i n te rm s o f a 1000 l i n e a r f o o t n e t f o r one u n i t o f e f f o r t ) . T h e re fo re : CPE _ C atch bv s ta n d a r d g e a r. (= Ys)_________________ Amount o f e f f o r t w ith s ta n d a r d g e a r (s E s) T hen, c o n v e r tin g th e t o t a l c a tc h an d e f f o r t t o a s t a n d a r d g e a r r e s u l t s in : ■ T o ta l E f f o r t w h e re : = V CFE = /*s Yfc = t o t a l y i e l d T h i s s t u d y w i l l u s e a c o n s t a n t o r r e a l p r i c e i n d o l l a r s f o r th e a n a ly sis . p ric e The r e a s o n f o r t h i s i s t o r e f l e c t o n l y t h e r e a l e l e m e n t o f o r in c o m e by rem o v in g t h e e f f e c t o f g e n e r a l l y i n c r e a s i n g p r i c e s . T h is i s a l s o commonly c a l l e d m e a su re d a s i f d e f l a t i o n i n w h ic h p r i c e o r in c o m e a r e t h e r e w a s no I n f l a t i o n o c c u r r i n g . T h is p r o c e s s i s a c c o m p lish e d by d iv i d i n g c u r r e n t d o l l a r s by th e p r i c e s e r i e s , c a l l e d th e consum er p r i c e in d e x (C P I). T he C PI m e a s u r e s t h e a v e ra g e ch an g e i n p r i c e s o v e r tim e i n a f i x e d m a rk e t b a s k e t o f g o o d s and s e r v i c e s . Method o f C a l c u l a t i n g CPI I n o r d e r t o f a c i l i t a t e t h e v i s u a l c o m p r e h e n s io n o f p r i c e s fr o m a b a se p e r io d t h a t i s m ore up t o d a t e , a c o n v e r s io n o f CPI from 1967 « 100 60 t o 1982 = 100 a s a s ta n d a r d r e f e r e n c e b a s e , I s u s e d . c o n v e r te d by d i v i d in g e a c h v a lu e i n th e The d a t a w i l l be 1967 b a s e s e r i e s by i t s a n n u a l a v e r a g e , an d t h e n ro u n d in g t h a t p ro d u c t t o o n e d e c im a l. s tu d y , 1982 In th i s f o r p r a c t i c a l p u r p o s e s , th e CPI i s p r e s e n te d i n te rm s o f t h r e e d e c im a ls w ith o u t m u l t i p l y i n g by 100. The c o n v e r s io n p r o c e s s fro m 1967 b a se t o 1982 b a s e i s shown b elo w : Rasa Y ear 1967 1982 1967 TOO 100 x 100 = 3 4 .6 28 9 .1 1982 2 8 9 .1 28Q .1 2 8 9 .1 (= 0 .3 4 6 1 x 100 = 100 (= 1 .0 0 0 ) Now, t h e 1 9 6 7 i n d e x o n 1982 b a s e w i l l b e 0 .3 4 6 w h ere 1982 i t s e l f h as in d e x o f 1 .0 0 0 . Most o f t h e d a t a and in f o r m a tio n u se d i n t h i s s tu d y a r e s u p p lie d by g overn m en t a g e n c ie s and i n s t i t u t i o n s s u c h a s : - F i s h e r y D i v i s i o n , M ic h ig a n D e p a r tm e n t o f N a t u r a l R e s o u rc e s , L a n s in g . - G r e a t L ak es F is h e r y L a b o r a to r y , U .S . F is h and W i l d l i f e S e r v ic e , Ann A rb o r. - M in is tr y o f N a tu r a l R e s o u rc e s , P ro v in c e o f O n ta r io , C anada. * U .S . g o v ern m e n t p u b l i c a t i o n s and s t a t i s t i c a l r e p o r t s , w hich a r e c i t e d i n t h e f o o t n o t e s and b ib l io g r a p h y o f t h i s s tu d y . The p e r io d o f t h i s s tu d y i s 23 y e a r s , from 196O t o 1982. I n t h i s s tu d y , two s t a t i s t i c a l co m p u ter p ro g ra m s, SPSS ( S t a t i s t i c a l P a c k a g e f o r t h e S o c i a l S c i e n c e s ) a n d TSP (T im e S e r i e s p a c k a g e s w e re u s e d . P ro c e sso r) T h ese p a c k a g e s a r e a v a i l a b l e a t th e M iohigan S t a t e U n iv e r s it y co m p u ter c e n t e r . CHAPTER IV DESCRIPTION AND ANALYSIS OF MICHIGAN'S GREAT LAKES COMMERCIAL FISHERY The S t a t e o f M ic h ig a n 's co m m ercial f i s h e r y f o r w h ite fis h , chubsf p e r c h , c a t f i s h , and a le w i f e s p e c i e s fro m 1960-1982 w i l l be d is c u s s e d i n t h i s c h a p te r. T he d i s c u s s i o n w i l l r e la tio n s h ip s fo r each s p e c ie s , In c lu d e p ro d u c tio n t h e g r o w th o f p r i c e and p ric e an d p r o d u c t i o n d u r in g a 23 y e a r p e r io d , t h e m eth o d s an d ty p e s o f g e a r u s e d , a s w e l l a s f i s h h a rv e s tin g e f f o r t . W h ite f is h (C o reg o n u s c lu p e a f o r m ls ) M ic h ig a n w h i t e f i s h la n d in g s h a v e in c r e a s e d tre m e n d o u s ly d u r in g t h e p e r io d 1 960-1982, from a low o f 550 th o u s a n d p o u n d s i n 1960 t o a h ig h o f 7 ,1 4 8 th o u s a n d p o u n d s i n 1 9 8 2 , a tw e lv e f o l d i n o r e a s e . (T a b le I V - 1 ) . The h ig h e s t a n n u a l i n c r e a s e o f p r o d u c tio n w as a b o u t 70 p e r c e n t i n I n 1980 t h e r e w as a n i n c r e a s e o f 51 p e r c e n t , w h ic h w as t h e h i g h e s t a b s o l u t e i n c r e a s e d u r i n g t h e 23 y e a r p e r i o d , a n i n o r e a s e o f th o u sa n d p o u n d s. 1961. 1 ,7 2 9 D u rin g t h e y e a r s 1980, 1981 and 1982, th e i n c r e a s e s i n w h ite f is h p r o d u c tio n w ere p a r t l y c o n trib u te d by t h e I n d i a n (n a tiv e A m e ric a n ) c a t c h e s o f 1 ,2 1 4 th o u s a n d ; 2,041 th o u s a n d ; and 2 ,4 3 0 th o u s a n d pounds i n e a c h y e a r , r e s p e c t i v e l y . T h e ir c a t c h w as n o t i n c l u d e d i n t h e a n n u a l M ic h ig a n f i s h e r y p r o d u c tio n r e p o r t s in c e i t was n o t c a t e g o r iz e d under S ta te lic e n s e f is h in g . M ich ig an D ep artm en t o f N a t u r a l R e s o u r c e s 62 63 T a b le IV -1. T ear W h ite f is h P r o d u c tio n from M ich ig an G re a t L ak es and I t s R e l a t i o n s h i p t o U .S . and t h e Whole G re a t L akes P r o d u c tio n 1960-1982 M ich ig an P ro d u c­ tio n ( in 1000 l b s . ) 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 551 939 809 712 1 ,0 9 8 1 ,3 9 3 1 ,7 4 4 1 ,3 9 9 1 ,5 4 8 2 ,0 2 0 1 ,9 0 5 2 ,9 8 5 3 ,9 4 9 3,4 5 1 2 ,9 6 1 2 ,9 5 4 3,451 2 ,9 1 6 3 ,2 3 9 3 ,4 1 2 5 ,1 4 1 * 6 ,7 9 7 * 7 ,1 4 8 * U .S . P ro d u c­ tio n ( in 1000 l b s . ) 830 1 ,2 9 9 1,0 2 7 900 1,4 2 3 1 ,6 4 8 1 ,9 7 2 1 ,6 3 4 1 ,7 7 0 2 ,3 6 1 2 ,3 7 5 4 ,0 8 1 4 ,7 9 2 4 ,8 2 8 4 ,6 9 9 4 ,9 1 8 5 ,8 2 8 5 ,2 3 5 5 ,2 4 8 5 ,1 1 6 7 ,7 6 8 * 1 0 ,468* 1 0 ,678* M ich ig an P r o d u c tio n as a % of Whole a ) US P ro d u c­ G .L. ( i n 1000 l b s . ) t i o n ( i n %) 4 ,4 1 9 5 ,2 0 7 4 ,6 6 7 4 ,2 5 7 4 ,6 5 3 4 ,8 8 5 4 ,7 8 4 4 ,2 5 9 4 ,6 7 5 5 ,3 1 7 5 ,2 4 4 6 ,3 9 3 6 ,9 9 2 6 ,8 1 2 7 ,0 5 8 7 ,3 6 7 8 ,3 8 0 8 ,4 4 6 9 ,0 1 0 8 ,1 3 8 11,514* 1 4 ,3 1 0 * 14,600* 66 72 79 79 77 85 88 85 87 86 80 73 73 71 63 60 59 56 62 67 66 65 67 M ich ig an P r o d u c tio n as a % of th e Whole G .L. P ro d u c­ t i o n ( i n %) 12 18 17 17 24 29 36 33 33 38 36 47 50 51 42 40 41 34 36 42 45 47 49 a) U .S . p r o d u c tio n p l u s O n ta rio (C anada) p r o d u c tio n . * I n o lu d e s I n d ia n c a t c h e s fro m M ich ig an j u r i s d i c t i o n s f o r 1980, 1981 and 1982 i n th e am ount: 1214; 2041 and 2430 th o u s a n d p o u n d s, re s p e c tiv e ly . S o u rc e s : F is h e r y D iv is io n , M ich ig an D ep t, o f N a tu r a l R e s o u rc e s . N a tio n a l O ce a n ic and A tm o sp h eric A d m in i s t r a ti o n . G r e a t L akes F is h e r y L a b o r a to r y , Ann A rb o r. M in is tr y o f N a tu r a l R e s o u rc e s , O n ta r io P r o v in c e , C anada. C a lc u la te d fro m d a t a s u p p lie d by s o u r c e s ab o v e f o r M ic h ig a n 's s h a r e o f p r o d u c tio n from US and GL. 64 i s s u e s a s e p a r a t e r e p o r t f o r t h i s o a to h . H o w e v e r, i n t h i s s tu d y b o th c a tc h e s a r e u sed f o r th e a n a ly s is . D u r in g t h i s p e r i o d , M ic h ig a n 's s h a r e o f U .S . w h i t e f i s h p r o d u c tio n v a r i e d from a low o f 42 p e r c e n t i n 1961 t o a h ig h o f 88 p e r c e n t i n 1966; w ith 67 p e r o e n t in 1982. The s h a r e f r o m t h e w h o le G r e a t L a k e s p r o d u c tio n a l s o f l u c t u a t e d from a low o f 11 p e r c e n t i n 1961 t o a h ig h o f 51 p e r c e n t i n 1 9 7 3 , w ith 49 p e r o e n t i n 1982. On th e a v e r a g e , M ich ig an c o n t r i b u t e d a b o u t 72 p e r c e n t o f U .S . w h i t e f i s h p r o d u c tio n and 35 p e r c e n t o f t o t a l G re a t L akes p r o d u c tio n . T a b le IV -2 . (T a b le I V - 2 ) . A verage P e r c e n ta g e o f M ich ig an P r o d u c tio n Over U .S . and th e Whole G r e a t L akes P r o d u c tio n f o r S e v e r a l F is h S p e o ie s 1960- 1982. S p e c ie s P e r c e n ta g e o f G re a t L akes P r o d u c tio n P e r c e n ta g e o f U .S . P r o d u c tio n W h ite f is h 72 35 Chubs 41 32 Y ellow P erch 16 4 C a tfis h 39 31 A le w ife 16 16 D a ta i n T a b le I V - 1 shows t h a t M ich ig an h a s h ad a s te a d y I n o r e a s e i n w h ite fis h p r o d u c tio n , e s p e c i a ll y c a u s e d by t h e d e c l i n e i n b u ild in g up to a fte r 1963. T h i s m ig h t h a v e b e e n s e a l a m p r e y , w i t h t h e w h i t e f i s h p o p u la tio n a s t a b l e l e v e l a f t e r r e c o v e r i n g fr o m t h e b i o l o g i c a l d i s r u p t i o n c a u s e d by s e a la m p r e y p r e d a t io n i n th e 1 9 5 0 's . (G h a n b a ri, 1977). A n n u a l c u r r e n t p r i c e s o f w h i t e f i s h o v e r th e p e r io d w ere s t a b l e and n o t so r e s p o n s iv e t o t h e q u a n t i t y o f w h i t e f i s h la n d e d . P r i c e s p e r pound 65 v a r i e d from a low o f 48 c e n t s i n 1971 t o a h ig h o f 86 c e n t s i n 1980. 1979 a n d The p r i c e i n 1982 was o n ly 8 c e n t s h i g h e r th a n t h e p r i c e i n 1960. H ow ever, r e a l p r i c e s ( a f t e r d e f l a t i n g by C P I), h a v e b e e n more r e s p o n s iv e t o t h e q u a n t i t y o f w h i t e f i s h la n d e d . T hat i s , a b o u t 65 p e r o e n t , from $ 1 .8 6 p e r pound i n T a b le I V - 3 ) . th e p r i c e s h a v e d e c l i n e d 1960 t o $ .6 5 in 1982. (S e e T h is m eans t h a t th e l a r g e r th e q u a n t i t y o f w h ite f is h p ro d u c e d , t h e lo w e r th e r e a l p r i c e p a id by th e consum er ( i n t h i s c a s e by th e w h o le s a le r ) and t h e l e s s re v e n u e p e r pound r e c e i v e d by t h e f is h e rm a n (p ro d u c e r). T h is m ig h t b e c a u se d by t h e n a t u r e o f c o m m e r c ia l f i s h i n g o p e r a t i o n s w h ic h r e q u i r e a l a r g e i n v e s t m e n t i n e q u ip m e n t. in v e s tm e n t h a s b e e n made i t i s d i f f i c u l t f o r t h e f is h e r m e n t o in v e s tm e n t to o th e r s e c to rs o r re so u rc e s . i n c r e a s e t h e i r c a t o h , by i n c r e a s i n g f i s h i n g in v e s tm e n t (E v e rh a rt and Toung, 1 9 8 1 ). T h ey m u s t, e ffo rt, T h is i s Once th e s h i f t th e th e re fo re , to m a in ta in t h e i r d o n e t o o f f s e t th e d ecre ase s in p ric e s . T h e t r e n d s o f a n n u a l w h i t e f i s h l a n d i n g s fro m t h e M ich ig an G re a t L akes w a t e r s , a n n u a l c u r r e n t and r e a l l a n d i n g p r i c e s d u r i n g a r e show n i n th e F ig u re IV -1. 1 9 6 0 -1 9 8 2 A n n u al w h i t e f i s h l a n d i n g s f l u c t u a t e d c o n tin u o u s ly w ith th e s h a r p e s t i n c r e a s e s fro m 1979 a n d 1980 t o 1981. A n n u a l r e a l p r i c e s d i d n o t move i n th e same d i r e c t i o n w ith p r o d u c ti o n ; b u t moved i n an o p p o s ite d i r e c t i o n and w i t h a dow n w ard t r e n d . cu rre n t p ric e s seem ed t o b e m o v in g a l m o s t h o r i z o n t a l l y . A nnual The r e l a t i o n s h i p b etw een r e a l p r i c e s an d t o t a l q u a n t i t y o f w h i t e f i s h l a n d e d c a n b e s e e n m o re e x p l i c i t y i n F i g u r e I V - 2 , w hich show s t h a t when th e t o t a l q u a n tity o f w h ite fis h in c r e a s e s o v e r tim e , th e r e a l p r i c e s a r e d e c lin in g . T ab le IV -3 . Year Annual C u rre n t and R eal Landing P r ic e s o f Lake W h ite f is h , Chub, Lake T ro u t, f e llo w P erch , C a tf is h and A lew ife p e r pound i n M ichigan 1960-1982 (1982 i s b ase y e a r) W h ite fis h C u rre n t R eal 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 S o u rc e s: .57 .5 2 .54 .52 .61 .51 .5 0 .57 .62 .6 0 .55 .48 .51 .5 9 .70 .6 8 .71 .73 .76 .86 .86 .7 5 .65 1.86 1.67 1.72 1.64 1 .9 0 1.56 1 .4 9 1 .6 5 1.7 2 1.58 1.3 7 1.14 1.18 1.2 8 1.3 7 1.22 1.2 0 1.16 1.13 1.1 4 1.0 0 .8 0 .65 Chub C u rre n t .19 .17 .16 .1 8 .17 .1 8 .18 .17 .16 .1 4 .17 .17 .26 .43 .50 .6 5 .68 .5 0 .57 .7 0 .66 .61 .86 R eal .62 .55 .51 .57 .56 .55 .54 .4 9 .44 .37 .42 .40 .60 .93 .98 1.16 1.1 5 .80 .8 5 .93 .77 .6 5 .86 Yellow P erch T ro u t C u rre n t R eal C u rre n t R eal .5 3 1.73 .58 1.87 .6 2 1.98 1.99 .6 3 .67 2 .0 9 2.11 .6 9 2 .0 5 .69 .61 1.76 .6 0 1.6 7 .5 8 1 .5 2 1.3 2 .53 .6 2 1.48 1.45 .63 .66 1.43 .7 2 1.41 1.24 .6 9 1.24 .7 3 .76 1.21 .76 1.13 .8 4 • 1 .1 2 .80 .94 .94 .8 9 1 .1 2 1 .1 2 .14 .1 5 .11 .11 .19 .1 9 .12 .13 .14 .17 .2 2 .2 8 .33 .37 .39 .44 .5 3 .5 2 .51 .7 0 .61 .81 1.0 2 .46 .4 8 .3 5 .35 .5 9 .5 8 .36 •38 .3 9 .4 5 .5 5 .67 .76 .80 .76 .7 9 .9 0 .83 .76 .93 .71 .86 1.0 2 C a tf is h Alewive C u rren t R eal C u rre n t R eal .22 .2 5 .26 .27 .27 .2 9 .31 .3 0 .2 7 .3 0 •32 .31 .31 .37 .36 .41 .41 .42 .41 .40 .42 .44 .4 3 .7 2 .81 .83 .85 .84 .8 9 .92 .87 .85 .7 9 .80 •74 .72 .80 .70 •73 .69 .6 7 .61 .53 .4 9 .47 .43 F is h e ry D iv is io n , M ichigan Dept o f N a tu ra l R eso u rces, L an sin g . N a tio n a l O ceanic and A tm ospheric A d m in is tra tio n . G re a t Lake3 F is h e r y L a b o ra to ry , Ann A rbor. M in is try o f N a tu ra l R eso u rces, O n ta rio P ro v in c e , Canada. R eal p r ic e s a r e c a lc u la te d from d a ta s u p p lie d by th e above s o u r c e s . .02 .01 .01 .0 2 .02 .0 2 .02 .01 .01 .01 .01 .01 .01 .01 .02 .01 .01 .01 .02 .0 2 .0 2 .0 2 .02 .0 7 .03 .0 3 .06 .06 .06 .06 .0 3 .0 3 .0 3 .0 2 .0 2 .0 2 .0 2 .04 .0 2 .0 2 .0 2 .0 3 .0 3 .02 .0 2 .02 Consumer P ric e In d ex (CPI) (1982=Base Yr.] .307 .310 .313 .317 .321 .327 .336 .346 .360 .380 .402 .420 .433 .460 .511 .558 .590 .628 .672 .752 .854 .942 1.000 WHITEFISH Quantity ( m illio n pounds) P r i c e (§) 1 .4 * 1.2 - O' 1.0 - 0.8 - ••*• 0. 2 - 1960 F ig u r e IV -1 . YEAR A nnual M ich ig an Lake W h ite f is h L andings, A nnual C u r r e n t P r i c e , and A nnual R eal P r i c e 1960 - 1982 p r o d u c tio n ----------- r e a l p ric e c u rre n t p ric e R e a l P r i e s ($) 2.0 1.8 1.6 65* 1 .4 l.Z •• 78 79 1.0 0.8 • 81 0.6 0 .4 0.2 0 1 F ig u r e IV -2 . 2 3 4 5 6 R e a l P r i c e an d Q u a n tity o f W h ite f is h L an d in g s i n M ichigan 1960 - 1982 7 8 (million poounds) 69 W h ile t h e a n n u a l g ro w th o f w h i t e f i s h la n d in g s d u r in g 1960-1982 was 1 2.4 p e r o e n t , th e r e a l p r i c e s h av e d e c re a s e d 4 .7 p e ro e n t a n n u a lly . A lth o u g h t h e r e a r e no d a t a a v a i l a b l e , i t i s r e c o g n iz e d t h a t th e ty p e s o f g e a r u se d to re c e iv e . c a tc h w h ite f is h in f lu e n c e s th e p r io e s fis h e rm e n w i l l W h i t e f i s h c a u g h t u s i n g g i l l n e t s f o r i n s t a n c e h a v e lo w e r v a lu e s th a n f i s h c a u g h t u s in g t r a p n e t s . 1 T h is i s due t o th e f a c t t h a t g i l l n e t s te n d t o i n j u r e q u a lity a n d k i l l t h e f i s h w h ic h r e s u l t s i n a s o o m p a re d w ith f i s h o a u g h t by t r a p n e t s . a lo w e r T h is i s one o f t h e r e a s o n s MDNR b a n n e d t h e u s e o f g i l l n e t s an d p r o m o te d t r a p n e t s i n c o m m e r c ia l f i s h i n g o n M ich ig an G re a t L akes w a t e r s . The m ain r e a s o n f o r t h e b an i s th e a c c i d e n t a l o r u n i n t e n t i o n a l c a tc h o f o t h e r f i s h s p e c ie s , e s p e c i a l l y la k e t r o u t . Many t y p e s o f g e a r a r e u s e d t o c a t c h w h i t e f i s h . IV -4 o n ly th e pound n e t ; 2 " g i l l n e t ; 4 - 6 " g i l l a n d l a r g e m esh t r a p H owever, i n T a b le n e t; s m a l l m esh t r a p ; n e t a r e p r e s e n t e d a s th e m ost oommon g e a r s u s e d . The number o f f i s h c a u g h t by pound n e t s h a s b een q u i t e s t a b l e o v e r t h e p e r io d 1960-1980 e x c e p t d u r in g th e l a t e 1 9 6 0 ' s and e a r l y 1970' s when th e nu m b er o f w h i t e f i s h cau g h t in c re a s e d s lig h tly . h a r v e s t w as 4 1 5 t h o u s a n d p o u n d s i n 1973* The r e c o r d a n n u a l Two in c h g i l l n e t s w ere n o t u s e d a s much a s th e 4 -6 " g i l l n e t s w h ich w ere d o m in an t i n th e 1 9 6 0 's and e a r l y 1970' s . A f t e r t h e MDNR b a n n e d t h e u s e o f g i l l n e t s i n 19 7 4 , th e am ount o f f i s h c a u g h t by 4 -6 " g i l l n e t s d e c r e a s e d d r a s t i c a l l y , fro m t h e h i g h o f 2 , 0 0 0 th o u s a n d pounds i n 1973 t o o n ly a b o u t 21 th o u s a n d pounds i n 1982. 1P e r s o n a l co m m u n icatio n w ith F is h e r y D iv is io n , M ichigan D ep artm en t o f N a tu r a l R e s o u rc e s . 70 T h ese d a t a d id n o t , h o w ev er, i n c l u d e a n y f i s h i n g e f f o r t c o n d u c te d by I n d ia n f is h e r m e n . W ith th e a b s e n c e o f g i l l n e t s , m ost f is h e r m e n s h i f t e d t o l a r g e mesh tra p n e ts. fis h T h is r e s u l t e d i n a s i g n i f i c a n t i n c r e a s e c a u g h t. i n t h e am o u n t o f I n 1 9 6 0 a b o u t 2 6 9 t h o u s a n d pounds w ere c a u g h t and t h a t number in c r e a s e d t o o v e r 4 ,5 0 0 th o u s a n d p o unds i n 1982. S m all mesh t r a p n e t s o n t h e o t h e r h a n d d id n o t i n c r e a s e i n u s e , and t h e am ount o f f i s h c a u g h t d e c r e a s e d t o a b o u t 28 th o u s a n d pounds o f f i s h c a u g h t i n 1982. D u r in g 1 9 7 0 , l a r g e mesh t r a p n e t s w ere n o t u s e d , a s shown i n T a b le IV -4 . T h is i s b e c a u s e i n 1970 t h e r e w ere c h a n g e s i n t h e d e f i n i t i o n o f t h e t y p e s o f g e a r u s e d ; d eep t r a p n e t s w e re ch an g ed t o l a r g e mesh t r a p n e t s , an d s h a llo w t r a p n e t s w e re ch a n g e d t o t h e sam e t i m e , fe e t, th e re fo re s m a l l m esh t r a p At t h e ' f i s h e r m e n w e r e n o t a llo w e d t o f i s h d e e p e r th a n 90 a ll fis h in g e ffo rts c a t e g o r iz e d u n d e r s h a llo w t r a p n e t s . u s in g deep tra p u n d e r l a r g e m esh t r a p n e ts ; n e ts w e re When t h e s e d e f i n i t i o n ch a n g e s to o k p la c e , u n f o r t u n a t e l y , t h e r e w a s no c a t c h u s i n g d e e p t r a p tra p n e ts. n e ts . n e ts li s t e d a l l c a t o h e s w ere l i s t e d u n d e r s m a ll mesh T h e r e f o r e , t h e e f f o r t from s m a ll mesh t r a p n e t in 1970 w as u se d t o oom pute CPE (C a tc h P e r - u n i t E f f o r t ) f o r th e l a r g e mesh t r a p n e t . Chubs (C o reg o n u s h o v i) M ic h ig a n ch u b l a n d i n g s , u n li k e w h i t e f i s h , d e c re a se d d r a s t i c a ll y d u r in g th e p e r io d I 960 t o 1982, from a h ig h o f 6 ,8 1 2 th o u s a n d p o u n d s i n 1960 t o a lo w o f 811 th o u s a n d pounds i n 1 9 8 2 , a d e c l i n e o f more th a n 85 p e r c e n t. M ich ig an chub l a n d in g s w ere o n ly a b o u t 196 th o u s a n d p o u n d s i n T ab le IV -4. Year 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 C atch and E f f o r t f o r D if f e r e n t Types o f G ear, and C atch p e r U n it o f E f f o r t (CPE) f o r S ta n d a rd Gear f o r Lake W h ite fis h i n M iehigan G reat Lakes W ater 1960-1982 Pound Net Catch E ffo rt 38,584 69,193 84,860 142,502 175,011 244,997 308,548 117,319 114,765 186,291 226,944 296,339 408,969 415,272 414,538 272,962 212,063 60,140 86,553 55,264 18,439 23,671 28,993 S o u rc e s: 1,109 1,422 1,363 1,537 1,939 1,773 2,2 6 7 1,390 1,821 1,727 1,964 1,754 1,489 1,902 1,425 1,333 872 354 505 397 197 196 115 2" G i l l Net Catch E f f o r t 2582 1868 714 180 274 619 2924 666 425 2985 1152 121 64 2877 8596 8060 70 5725 159 16 397 1411 10 0 0 3 0 4 47 52 93 52 234 133 10 15.6 112.8 256.3 126.4 9 8 .7 230.1 56.6 2 .6 49 80 2 .4 4 -6 ” G i l l Net C atch E ffo rt 163,031 370,046 278,850 299,536 540,565 708,510 1 , 012,321 812,294 943,092 1 ,1 9 7 ,5 6 0 935,178 1 ,6 68,946 1 ,7 99,482 2 ,0 6 5 ,2 2 7 1,3 0 7 ,3 8 8 976,477 887,101 568,663 522,264 515,719 468,031 118,811 21,099 15,982 30,978 21,3 7 3 18,319 36,707 45,941 50,688 43,141 50,341 51,964 40,209 46,708 44,716 47,241 38,440 28,910 26,102 14,835 15,025 15,251 11,064 2,1 0 6 252 S m all Mesh T rap C atch E ffo rt 61,308 125,358 167,855 159,831 214,708 314,888 114,607 104,475 107,064 545,599 739,043 612,795 18,469 46,900 2,547 10,734 27,155 17,786 13,748 16,741 33,442 29,066 28,013 1,766 2 ,1 4 2 2,4 6 9 2 ,6 1 8 2,65 2 2,9 2 2 1,748 1,320 1,637 4,131 4 ,6 7 3 2 ,9 3 2 99 277 99 314 248 471 586 554 693 879 743 L arge Mesh T rap C atch E ffo rt 269,389 371,190 239,686 72,094 104,805 121,616 304,460 353,091 381,912 83,841 0 403,197 1,265,491 919,268 1,226,197 1,68 0 ,5 4 5 2 , 315,862 2 ,2 9 0 ,7 7 7 2 ,4 7 4 ,5 5 3 2,686,741 3 ,2 5 8 ,7 8 5 4 ,4 2 3 ,1 5 4 4,511,606 CPE f o r Large Mesh T rap 2030 2909 2110 1314 1050 1555 1913 2342 2856 542 0 1954 4716 4387 5632 6961 9014 9816 10317 11537 13299 14814 15562 C a lc u la te d from raw d a ta s u p p lie d by F is h e ry D iv is io n , M ichigan D ep t, o f N a tu ra l R esources f o r 1960- 1970. F is h e ry D iv is io n , M ichigan D ept, o f N a tu ra l R eso u rces f o r 1971-1982 d a ta . 132.70 127.60 113.60 54.87 99.81 78.21 159.15 150.76 133.72 154.69 158.15 206.34 268.34 209.54 217.72 241.42 256.92 223.18 239.85 232.88 245.04 298.58 289.91 72 1982, e x c lu d in g th e I n d ia n c a t c h ( a s much a s 6 1 4 .8 th o u s a n d p o u n d s ) f o r th is y e a r. T he d o w n tu r n o f c h u b p r o d u c t i o n m ig h t h a v e b e e n o a u s e d b y t h e c o m b in a tio n o f o v e r f i s h i n g and c o m p e titio n w ith a new s p e c i e s , a le w ife . O v e r f is h in g o f ch u b s w as due t o th e f is h e r m e n s h i f t i n g t h e i r e f f o r t from t h e d e o l i n i n g la k e t r o u t and w h i t e f i s h , w hich had b e e n a f l i o t e d s e a la m p re y , to th e d eep w a te r c is c o e s . by t h e A d d i t i o n a l l y , th e u s e o f th e o t t e r tr a w l w h ich c a p t u r e d l a r g e n u m b e rs o f y o u n g c h u b s i n t h e l a t e 1 9 5 0 's a n d e a r l y 1960's f u r t h e r a g g r a v a t e d t h e d e c r e a s e i n th e chub p o p u la tio n s to c k s (J o h n s o n , 1 9 8 1 ). As a r e s u l t o f t h i s d e c r e a s e i n 1976 a l l o f t h e L ak e M io h ig a n c h u b f i s h e r i e s w ere c l o s e d e x c e p t f o r s m a ll a s s e s s m e n t f i s h e r i e s i n th e r e s p e c t i v e s t a t e s . T h is p o l i c y w a s im p o s e d t o e n a b l e t h e o h u b p o p u l a t i o n s t o c k t o re n e w a n d grow t o i t s fo rm e r le v e l. W h i l e M i c h i g a n c h u b p r o d u c t i o n d e o l i n e d fro m t h e 1 9 6 0 's , its p r o d u c tio n s t i l l made u p a l a r g e p o r t i o n o f U .S . a s w e ll a s G r e a t L a k e s p r o d u c t i o n , w h ic h i n d i c a t e d t h a t t h i s d e c l i n e was n o t c o n f in e d o n ly t o th e M io h ig an p r o d u c ti o n , a s c a n be s e e n i n T a b le IV -5 . In s p ite o f th i s d e c r e a s e i n p r o d u c tio n , M ic h ig a n 's s h a r e o f t h e ohub p r o d u c tio n was th e h i g h e s t d u r in g th e p e r io d 1975 t o 1978 w ith an a v e ra g e s h a r e o f a b o u t 54 p e r c e n t o f th e U .S . chub p r o d u c tio n o v e r t h i s tim e . p r o d u c tio n d ro p p e d t o M ic h ig a n 's s h a r e o f its l o w e s t l e v e l , 19 p e r c e n t i n 1 9 8 2 . T h is * d e c l i n e w as c a u s e d by t h e MDNR's s lo w e r r e o p e n in g o f t h e chub f i s h e r y f o r co m m ercial f i s h i n g th a n W i s c o n s i n 's , p a rtly b ecau se o f p e s tic id e c o n t a m i n a t i o n s f o u n d i n M ich ig an c h u b s . M ic h ig a n 's s h a r e o f th e w hole G re a t L akes p r o d u c tio n a l s o v a r i e d from a h ig h o f 42 p e r c e n t i n a lo w o f 17 p e r c e n t i n 1982. 1970 t o O v er t h e p e r io d o f 1 9 6 0 -1 9 8 2 , M ichigan 73 T a b le IV -5 . Y ear Chub P r o d u c tio n fro m M ich ig an G re a t L ak es and I t s R e l a t i o n s h i p t o U .S . and t h e Whole G r e a t L akes P r o d u c tio n 1960-1982 M ich ig an P ro d u c­ tio n (in 1000 l b s . ) 6 ,8 1 2 6 ,4 9 4 6 ,3 3 1 4 ,8 9 1 3 ,0 1 0 5 ,2 9 6 3 ,9 0 3 4 ,7 9 3 3 ,7 1 9 3 ,4 3 9 4 ,6 7 4 3 ,2 0 0 3 ,5 0 1 3 ,0 8 8 2 ,4 2 8 1 ,5 3 9 1,071 844 814 805 773* 797* 8 1 1« 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 U .S . P ro d u c­ tio n (in 1000 l b s . ) 1 6 ,8 5 4 1 6 ,5 1 6 1 4 ,4 2 8 1 1 ,0 2 3 7 ,2 1 8 1 0 ,9 2 0 9 ,9 9 2 1 1 ,3 1 3 11,126 1 0 ,1 5 7 1 0 ,9 7 7 8 ,8 7 9 7 ,8 4 8 6 ,9 6 3 5 ,6 8 5 2 ,8 2 4 1 ,9 3 9 1 ,5 8 2 1 ,4 7 4 2 ,3 7 8 2 ,6 3 4 * 3 ,6 0 3 * 4 ,1 5 3 * M ich ig an P r o d u c tio n as a % o f Whole a ) G .L. ( i n US P ro d u c­ 1000 l b s . ) t i o n ( i n %) 1 8 ,8 7 6 1 9 ,508 17,253 1 3 ,3 5 2 9 ,2 5 3 1 2 ,8 1 2 11,257 1 2 ,4 7 8 H ‘,807 1 0 ,6 1 7 1 1 ,2 5 9 9 ,6 8 1 8 ,5 6 7 7 ,9 0 7 6 ,7 3 4 4 ,1 4 0 3,551 2 ,9 2 0 2 ,7 1 4 3 ,4 8 8 3 ,5 1 6 * 4 ,4 6 9 * 4 ,8 3 8 * 40 39 44 44 42 49 39 42 33 34 43 36 45 44 43 54 55 53 55 34 29 22 19 M iohigan P r o d u c tio n as a % o f th e Whole G.L. P ro d u c­ t i o n ( i n %) 36 33 37 37 33 41 35 38 31 32 42 33 41 39 36 37 30 29 30 23 22 18 17 a) US p r o d u c tio n p lu s O n ta rio (C an ad a) p r o d u c tio n . * I n o lu d e s I n d ia n c a t c h e s from M ich ig an j u r i s d i c t i o n s f o r 1980, 1981 and 1982 i n th e am ount: 110. 1; 5 0 4 .1 and 6 1 4 .8 th o u s a n d p o u n d s, re s p e c tiv e ly . S o u rc e s : F is h e r y D iv is io n , M ich ig an D ep t, o f N a tu r a l R e s o u rc e s . N a tio n a l O cean io and A tm o sp h eric A d m in is tr a tio n . G re a t L akes F is h e r y L a b o r a to r y , Ann A rb o r. M in is tr y o f N a tu r a l R e s o u rc e s , O n ta r io P r o v in c e , C anada. C a lc u la te d fro m d a t a s u p p lie d by s o u r c e s ab o v e f o r M ic h ig a n 's s h a r e o f p r o d u c tio n from US and GL. 74 h a r v e s te d a n a v e ra g e o f 41 p e r c e n t o f t h e U .S . o h u b p r o d u c t i o n a n d 32 p e r c e n t o f t o t a l G re a t L ak es p r o d u c tio n , a s shown i n T a b le IV -2 . The c u r r e n t a n n u a l p r i c e o f ch u b s w ere c o n s i d e r a b l y r e s p o n s i v e t o t h e q u a n t i t y o f c h u b s la n d e d . The p r i c e p e r pound h a s in c r e a s e d from 19 c e n t s i n 1960 t o 86 c e n t s i n 1982, an in o r e a s e a b o u t 350 p e r c e n t. T h is i n d i c a t e s t h a t t h e c u r r e n t p r i c e o f ch u b s r i s e s when t h e q u a n t i t y p ro d u ced h a s d e c l in e d o v e r a p e r io d . However, d u r in g th e p e r io d 1960 t o 1 9 7 1 , t h e c u r r e n t p r i c e d e c l i n e d s l i g h t l y from 19 c e n t s i n 1960 t o 17 c e n ts in s h a rp ly , 1971. u n til A fte r 1971, th e c u r r e n t p r io e s 1982. In te rm s o f re a l began to p ric e s , in o re a s e ch u b s w e re l e s s r e s p o n s iv e t o t h e q u a n t i t y la n d e d e s p e c i a l l y d u r in g t h e p e r i o d 1960 t o 1971 w h e re r e a l p r i c e s d e o r e a s e d from 62 c e n t s i n 1960 t o 40 c e n t s i n 1971* In 1972, th e p r i c e in c r e a s e d to 60 c e n t s i n c r e a s e t o t h e h i g h o f $ 1 .1 6 i n 1975. and c o n tin u e d to D u rin g t h e 1972-1982 p e r io d , r e a l p r i c e s w ere o b v i o u s l y m o re r e s p o n s i v e t o t h e q u a n t i t y o f c h u b s p ro d u c e d . The chub p r o d u c tio n o v e r th e tw e n ty y e a r p e r io d h a s d e c r e a s e d by 9*2 p e r c e n t a n n u a lly w h ile th e o u r r e n t and r e a l p r i c e s h av e I n c r e a s e d by 7 .1 a n d 1 .5 p e r c e n t , r e s p e c t i v e l y . The tr e n d o f th e a n n u a l M ichigan chub l a n d i n g s , a n n u a l c u r r e n t , and r e a l p r i c e s a r e p r e s e n t e d i n F i g u r e IV -3 . T he a n n u a l c h u b p r o d u c t i o n seem 's t o f l u c t u a t e w ith a downward tr e n d and l e v e l s o f f a f t e r 1976. T he a n n u a l r e a l p r i o e s a l s o m oved dow nw ard b e f o r e t u r n i n g upw ard a f t e r 1971. moved upw ard a f t e r 1971. The r e l a t i o n s h i p A nnual o u r r e n t p r i c e s a l s o b e tw e e n a n n u a l r e a l p r i c e s and t o t a l p r o d u c tio n o f ch u b s i s p r e s e n te d i n F ig u r e IV -4 . T h ere a r e s e v e r a l ty p e s o f g e a r u s e d t o h a r v e s t ch u b s i n M ic h ig a n 's G r e a t L a k e s w a te r s su ch as s e in e n e t , o t t e r t r a w l , 2 " g i l l n e t , 3" g i l l n e t , 4 -6 " g i l l n e t , and l a r g e mesh t r a p n e t . I n t h i s s t u d y , o n l y tw o CHUBS Q u a n tity ( m illio n pounds) P r i c e ($) 1. 2 - 7 1. 0 - 0. 8 “ - • — ■ - 3 0. 2 - 1960 F ig u re IV -3. 62 64 66 68 70 72 74 76 78 80 A nnual M ichigan Chub L an d in g s, A nnual C u r r e n t P r i c e s , and R eal P r ic e s 1960 - 1982 ( i n 1982 d o l l a r s ) ----------------------- p ro d u c tio n r e a l p ric e c u rre n t p ric e 82 A nnual Y ear Beal Price ($) • 73 0 .9 - • 65 • 67 QUANTITY (million pounds) F ig u r e 3V -4. R eal P r i c e an d Q u a n tity o f Chub la n d in g s i n M ichigan 1960-1982 77 m ain ty p e s o f g e a r a r e p r e s e n te d , th e 2" g i l l n e t and 4 -6 " g i l l n e t , as shown i n T a b le IV -6 . C hubs w e re S u p e r io r . c a u g h t fro m L ake M i c h i g a n , L ak e H u ro n , an d L ak e Lake M iohigan c h u b s a r e c o n s i d e r e d s u p e r i o r i n q u a l i t y to t h o s e fro m o t h e r l a k e s and t h e r e f o r e r e c e iv e a prem ium p r i c e (J o h n s o n , 1 9 8 1 ). Chubs u se d f o r human co n su m p tio n a r e u s u a l l y smoked and s o l d i n two g ra d e s: G rade one smoked c h u b s h av e a c o u n t o f 3 0 0 o r l e s s chubs p er 100 p o u n d s ; g r a d e tw o smoked ch u b s w h ich a r e s m a l le r f i s h h av e a c o u n t o f more th a n 300 p e r 100 p o u n d s. Y ellow P e rc h (P e r o a f l a v e s c e n s l T he y e l l o w p e r c h h a r v e s t fro m M i c h i g a n 's G r e a t L a k e s w a te r s i s f a c i n g s i m i l a r p ro b lem . P r o d u c tio n h a s d e c r e a s e d d r a s t i c a l l y from a b o u t 2 , 0 0 0 th o u s a n d pounds i n 1960 t o a lo w o f 197 th o u s a n d pounds i n 19 82 , a d e c r e a s e o f a b o u t 90 p e r c e n t , a s shown i n T a b le IV -7 . n o t c o n fin e d to M io h ig a n c a t c h , b u t a l s o r e l a t e s T h is d o w n tu r n i s t o o v e r a l l U .S . p r o d u c tio n w hich d e o r e a s e d from a h ig h o f 1 2 ,0 0 0 th o u s a n d p o u n d s i n 1962 to a lo w o f 2 , 3 0 0 t h o u s a n d p o u n d s i n p e r c e n t fro m t h e 1960 h a r v e s t . 1 9 8 2 , a d e o r e a s e o f a b o u t 78 A v erag e a n n u a l p r o d u c t i o n i n M io h ig a n d u r in g th e 1 9 6 0 's was a b o u t 1 ,8 0 0 th o u s a n d p o u n d s. r a p id ly in th e a n n u a l ly . 1970's to P r o d u c tio n d e c r e a s e d an a v e ra g e o f a b o u t 300 th o u s a n d pounds T h is d e c r e a s e was d e t e c t e d i n th e l a t e 1 9 6 0 's a s p e rc h s to c k s showed s ig n s o f s t r e s s and d e t e r i o r a t i o n (H artm an , e t a l . , 1 9 8 0 ) . M ore im m atu re p e rc h w e re c a u g h t i n th e m id -19 70 ' s th a n i n th e 1960' s , and th e a v e ra g e t o t a l le n g t h o f p e rc h i n t h e c a t c h e s a l s o d e c r e a s e d fro m o v e r 8 78 T a b le XV-6 . C atoh an d E f f o r t f o r D i f f e r e n t T ypes o f G ear, an d C atch p e r U n it o f E f f o r t (CPE) f o r S ta n d a rd G ear f o r Chubs I n M ich ig an G re a t L akes W ater 1960-1982 2" G i l l N et 4 -6 " G i l l N et C atoh E ffo rt C atoh 1960 5 ,4 2 3 ,5 5 4 1 3 6,80 0 1 ,6 0 0 - 3 9 .6 5 1961 5 ,6 6 4 ,2 7 7 123,751 703 - 4 5 .7 7 1962 5 ,3 0 9 ,7 5 3 1 2 3 ,8 8 9 123 - 4 2 .8 6 1963 4 ,3 6 1 ,4 9 2 110,991 - 9 3 9 .3 0 1964 2 ,6 2 6 ,4 0 0 5 5 ,8 4 3 42 - 4 7 .0 3 1965 5 ,0 4 5 ,9 4 3 9 2 ,7 0 3 208 16 5 4 .4 3 1966 3 ,7 1 1 ,6 1 3 6 4 ,1 3 4 3 ,1 4 9 85 5 7 .8 7 1967 4 ,6 7 1 ,0 7 7 6 6 ,4 6 0 722 278 7 0 .2 8 1968 3 ,7 0 2 ,9 7 7 4 2 ,7 0 5 496 166 86.71 1969 3 ,3 8 8 ,8 1 5 2 6 ,6 4 7 1 ,4 3 5 294 127 .1 7 1970 4 ,6 0 1 ,5 0 9 3 5 ,9 0 0 2 ,1 5 6 193 1 2 8.20 1971 3 ,1 7 3 ,4 5 7 3 1 ,8 4 3 2 5 ,7 9 6 451 9 9 .6 6 1972 3 ,4 9 9 ,0 7 6 42,591 568 12 8 2 .1 6 1973 1974 3 ,0 5 9 ,8 2 5 4 5 ,2 2 8 5 ,9 5 4 183 6 7 .6 5 2 ,4 1 0 ,3 5 4 3 8 ,0 9 7 5 ,2 0 2 536 6 3 .2 7 1975 1 ,5 3 0 ,1 1 7 2 5 ,3 0 4 9 ,2 3 8 63 6 0 .4 7 1976 1 ,0 7 1 ,4 5 9 17,7 4 9 0 0 6 0 .3 7 1977 8 4 3 ,7 3 8 1 2 ,1 5 5 0 0 69.41 1978 8 1 3 ,8 4 9 12,554 1 3 6 4 .8 3 1979 8 0 4 ,8 6 2 1 1 ,9 3 9 0 0 67.41 1980 6 6 3 ,0 9 2 9,9 6 1 0 0 6 6 .5 7 1981 2 9 3 ,1 2 8 5 ,0 2 8 0 0 5 8 .3 0 1982 1 9 6 ,1 7 8 3 ,0 2 7 2 3 6 4 .8 1 S o u rc e s: E ffo rt CPE f o r 2" G i l l N et Y ear C a lc u la te d fro m raw d a t a s u p p lie d by F i s h e r y D iv i s i o n , M ich ig an D e p t, o f N a tu r a l R e s o u rc e s f o r 1960-1970 F is h e r y D iv is io n , MDNR f o r 1971-1982 79 T a b le IV -7 . Y ear M ich ig an P ro d u c­ tio n (in 1000 l b s . ) 1,9 2 2 2 ,2 3 4 1 ,5 0 5 1 ,6 7 2 3,2 5 6 1 ,8 2 0 1 ,8 5 0 1 ,7 0 3 1 ,2 3 8 1 ,1 6 4 588 594 346 320 232 271 323 260 169 168 249* 247* 197* 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 a) Y ellow P e rc h P r o d u c tio n fro m M ich ig an G re a t L akes and I t s R e l a ti o n s h i p t o U .S . and t h e Whole G re a t L akes P r o d u c tio n 1960-1982 U .S. P ro d u c­ tio n ( in 1000 l b s . ) 10,238 9,3 5 1 1 2 ,0 2 4 1 1 ,2 7 5 8 ,3 0 3 5 ,4 9 9 6 ,1 6 4 5 ,8 0 5 5 ,3 0 3 4 ,9 2 6 4 ,2 8 3 3 ,9 9 5 3 ,3 3 8 3 ,0 0 2 3 ,9 5 7 3 ,0 4 0 3 ,1 2 5 4,1 5 1 3 ,4 7 0 4 ,4 6 0 4 ,2 5 2 * 3 , 680* 2 ,2 5 1 * M ich ig an P ro d u c tio n Whole a ) as a % o f G .L. ( i n US P ro d u c 1000 l b s . ) t i o n ( i n %) 2 2 ,5 3 9 2 7 ,9 5 9 3 3 ,6 6 3 2 9 ,9 4 6 17,666 2 4 ,9 6 4 2 7 ,3 1 6 2 8 ,5 3 6 30,271 3 5 ,4 3 3 2 5 ,6 0 3 19,2 7 2 2 0 ,1 7 4 2 2 ,0 7 7 17,3 6 9 12,489 9 ,2 4 4 13,856 13,482 17,628 17,918* 1 4 ,0 0 8 * 13,123* 19 24 13 15 39 33 30 29 23 24 14 15 10 11 6 9 10 6 5 4 6 7 9 M iohigan P r o d u c tio n as a % of t h e Whole G .L. P ro d u c­ t i o n ( i n Jf) 8 8 4 6 18 7 7 6 4 3 2 3 2 1 1 2 3 2 1 1 1 2 2 US p r o d u c tio n p lu s O n ta r io (C anada) p r o d u c tio n . I n o lu d e s I n d ia n c a to h e s from M ich ig an j u r i s d i c t i o n s f o r 1980, 1981 and 1982 i n t h e am ount: 5 4 .1 ; 6 1 .6 and 4 1 .6 th o u s a n d p o u n d s, re s p e c tiv e ly . S o u rc e s : F is h e r y D iv is io n , M ich ig an D ep t, o f N a tu r a l R e s o u rc e s . N a tio n a l O cean ic an d A tm o sp h erlo A d m in is tr a tio n . G re a t L akes F is h e r y L a b o r a to r y , Ann A rb o r. M in is tr y o f N a tu r a l R e s o u rc e s , O n ta r io P r o v in c e , C anada. C a lc u la te d from d a t a s u p p lie d by s o u r c e s above f o r M ic h ig a n 's s h a r e o f p r o d u c tio n from US an d GL. 80 in c h e s i n t h e 1 9 6 0 's t o l e s s th a n 8 i n c h e s i n t h e 1 9 7 0 's . M i c h i g a n 's s h a r e o f U .S . p e r c h p r o d u c t i o n a l s o d e c l i n e d fro m a b o u t 25 p e r c e n t a n n u a lly i n th e 1 9 6 0 's t o a b o u t 9 p e r c e n t i n th e 1 9 7 0 's . C o n c e rn o v e r t h e d e t e r i o r a t i o n o f y e llo w p e rc h s t o c k p ro m p ted s t a t e a g e n c ie s s h a r in g t h e management o f y e llo w p e rc h on Lake E r i e t o e s t a b l i s h a Y e llo w P e r c h T e c h n i c a l C o m m itte e i n F is h e r y Com m ission. in te rim 1975 u n d e r t h e a u s p i c e s o f t h e G r e a t L a k e s The c o m m itte e , w h io h w as d i r e c t e d t o d e v e l o p a n m a n ag em e n t s t r a t e g y to p r o t e c t p e r c h i n w e s t e r n L ak e E r i e , recommended i n c r e a s i n g t h e minimum s i z e l i m i t (MSL) fro m 8 . 0 i n c h e s t o 8 .5 I n c h e s . T h is ch an g e was e x p e c te d t o p r o t e c t and r e s t o r e th e y e llo w p e rc h p o p u la tio n t o fo rm e r l e v e l s o f ab u n d an ce w ith g r e a t e r s t a b i l i t y . Even th o u g h t h i s reco m m en d atio n w as a c c e p te d , i t was n o t Im posed by m ost o f th e s t a t e s , an d t h e c o n d i tio n o f t h e y e llo w p e r c h h a s n o t im p r o v e d . On th e o t h e r h an d , i n M ich ig an w a te r s su ch a s Lake E r i e , Lake H uron, and Lake M ic h ig a n ; p e rc h f i s h i n g w as r e s t r i c t e d to fa v o r s p o rt f is h in g r a t h e r t h a n t o p r o t e c t a n d r e s t o r e p e r c h s to c k s a s recommended by th e co m m itte e . B o th t h e a n n u a l c u r r e n t an d t h e r e a l p r i c e s o f y e llo w p e rc h o v e r th e p e r io d w ere a p p a r e n tly r e s p o n s iv e t o t h e q u a n t i t y o f p e r o h l a n d e d , a lth o u g h d u r in g th e i n T a b le IV -3 . pou n d i n 1 9 6 0 's th e p r i c e s w ere r e l a t i v e l y s t a b l e , a s shown A nnual c u r r e n t p r i c e s h av e in c r e a s e d fro m 14 c e n t s p e r 19 60 t o $ 1 .0 2 in 1 9 8 2 , an i n o r e a s e o f m ore th a n 600 p e r o e n t . A nnual r e a l p r i c e s a l s o h av e i n c r e a s e d a b o u t 120 p e r c e n t, fro m 46 c e n t s in 19 60 t o $ 1 .0 2 in 1982, w hich i n d i c a t e s t h a t th e d e c l i n e i n q u a n t i t y o f y e llo w p e ro h a v a i l a b l e h a s c o n t r i b u t e d t o a n i n c r e a s e i n p r i c e . A nnual y e llo w p e r c h h a r v e s t f l u c t u a t e d c o n s id e r a b ly b etw een 1960 and 1966 when t h e l e v e l o f h a r v e s t re a c h e d i t s p eak i n 1 9 6 4 , an d a f t e r 81 1966 b eg an t o d e c l in e s h a r p ly u n t i l 1970, a s shown i n F ig u r e IV -5 . 1972 t o From 1982 p e r o h p r o d u c t i o n seem e d t o be l e v e l i n g o f f below a h a l f m i l l i o n pounds a n n u a l l y . B o th a n n u a l c u r r e n t a n d r e a l p r i o e s m oved u p w a rd , a lm o s t p a r a l l e l w ith eac h o t h e r . Over th e p e r io d 1960 t o 1982, th e l e v e l o f p e rc h p r o d u c tio n d e c r e a s e d a b o u t 9 .8 p e r c e n t a n n u a l l y . At t h e sam e tim e th e o u r r e n t and r e a l p r i c e s o f p e r c h h ad an a n n u a l g ro w th o f 9 .5 and 3 . 7 p e r c e n t , r e s p e c t i v e l y . The r e l a t i o n s h i p b e tw e e n r e a l p r i c e and q u a n t i t y o f y e llo w p e ro h i s p r e s e n te d i n F ig u r e IV -6 . Most o f M ic h ig a n 's y e llo w p e r c h w e re c a u g h t fro m L a k e s M io h ig a n , H u ro n , S u p e r i o r , an d E r i e . The m ain g e a r u s e d t o h a r v e s t y e llo w p e rc h from M iohigan G re a t L ak es w a te r s i s p r e s e n te d i n T a b le IV -8 . T h ere a r e s e v e r a l o t h e r ty p e s o f g e a r su c h a s pound n e t , s e t h o o k s, and i»-6 " g i l l n e t w h ich w ere a ls o u s e d i n t h e f i s h i n g e f f o r t . o f g e a r show n i n T a b l e I V - 8 , t h e s m a l l m esh t r a p n e t i s dom in an t g e a r i n u s e . th e Among t h e t h r e e ty p e s t h e m ost Two in c h g i l l n e t h a d b e e n u s e d h e a v i l y d u r i n g 1 9 6 0 's w h ic h a c c o u n t e d f o r a b o u t 50 p e r c e n t o f t h e t o t a l c a tc h d u r in g t h a t tim e . A fte r 1972, h o w e v e r, a lm o s t a l l c a t c h e s w e re m ade u s in g s m a ll mesh t r a p n e t s . C atfish (Io ta lu ru s PunctatusV T he p r o d u c t i o n o f c a t f i s h i n M ic h ig a n w a t e r s o v e r t h e 23 y e a r p e r io d h a s in c r e a s e d fro m 370 th o u s a n d p o u n d s i n 1960 t o 6 9 2 t h o u s a n d pounds i n 1982, an i n c r e a s e o f a b o u t 87 p e r c e n t . D e s p ite a c o n s id e r a b le f l u c t u a t i o n s i n a n n u a l c a t f i s h la n d i n g s , e s p e c i a l l y d u rin g th e 1960's w here p r o d u c tio n was d e c l i n i n g , p r o d u c tio n b eg an t o i n c r e a s e s t e a d i l y i n t h e mid 1970' s u n t i l 1982. YELLOW PEFCH Q u a n tity ( m illio n pounds) 4 .0 P r i c e ($) 1.0 - 3 .5 3 .0 - 1 .5 - 1960 62 F ig u r e IV -5 . 64 66 68 .7 0 72 74 76 78 80 A nnual M ichigan P e rc h L an d in g sfA nnual C u r re n t P r i c e , and A nnual R eal P r i c e 1960 - 1982 p ro d u c tio n r e a l p ric e c u rre n t p ric e 1.0 P e a l P r i c e ($) 1.0 0 .9 0.8 7 5 .• . • • •7 2 0 .7 0.6 • 65 69 • 0 .3 6 F ig u r e IV -6 . 12 18 24 30 R e a l P r i c e an d Q u a n tity o f Y ellow P e rc h T en d in g s i n M ichigan 1960 - 1982 36 QUANTITY (x 105 pounds) 84 T a b le IV -8 . C atch an d E f f o r t f o r D i f f e r e n t T ypes o f G e a r, an d C atch p e r U n it o f E f f o r t (CPE) f o r S ta n d a rd G ear f o r Y ellow P e rc h i n M ich ig an G re a t L ak es W ater 1960-1982 Sm. Mesh T rap 2" G i l l N et L g. Mesh T rap C atoh E ffo rt CPE f o r Sm. Mesh T rap 17165 80 25 2 1 .9 9 369428 6889 300 35 5 3 .6 3 17780 274467 13545 91 45 2 0 .2 6 1090759 19566 298574 12655 0 0 2 3 .5 9 1964 1281326 33076 291086 12305 143 4 23 .6 6 1965 753030 18362 419427 11311 10322 288 3 7 .0 8 1966 632674 9068 883119 10834 0 0 81.51 1967 590682 8614 732485 8909 0 0 8 2 .2 2 1968 481841 7127 603102 7621 5 12 7 9 .1 4 1969 459942 7391 477845 7583 1802 62 6 3 .0 2 1970 261839 2559 318338 5427 0 0 5 8 .6 6 1971 404228 3596 184978 5760 40 24 32 .1 1 1972 20406 259 321456 6460 148 90 4 9 .7 6 1973 1 11 313499 7343 141 45 4 2 .6 9 1974 0 0 2296 07 6502 3 4 3 5 .3 1 1975 0 0 268911 7638 2 4 35.21 1976 15 0 321925 7201 0 0 44 .7 1 1977 0 0 259112 6546 50 1 3 9 .5 8 1978 0 0 168609 5731 71 3 2 9 .4 2 1979 0 0 167673 5144 90 20 3 2 .6 0 1980 0 0 193840 4895 0 0 3 9 .6 0 1981 0 0 182337 5428 75 4 3 3 .5 9 1982 0 0 150877 5669 0 0 26.61 Y ear C atoh 1960 E ffo rt C atch 1325177 25436 377411 1961 1446112 35434 1962 879678 1963 S o u rces: E ffo rt C a l c u la te d fro m raw d a t a s u p p lie d by F is h e r y D iv is io n M ich ig an D e p t, o f N a tu r a l R e s o u rc e s f o r 1960 -1 9 7 0 . F is h e r y D iv is io n , M lo h ig an D ep artm en t o f N a tu r a l R e s o u rc e s f o r 1970- 1982. 85 On t h e a v e r a g e , M ic h ig a n c a t f i s h p r o d u c tio n h a s made up a b o u t 39 p e r c e n t o f U .S . p r o d u c tio n d u r in g th e p e r io d 1960 t o 1982, w h ic h v a r i e d fro m a lo w o f 14 p e r c e n t i n 1968 t o a h ig h o f 75 p e r c e n t i n 1982 (show n i n T a b le s IV -2 and I V - 9 ) . I t a ls o c o n s t i t u t e d a n a v e r a g e o f a b o u t 31 p e r c e n t o f t h e w h o le G r e a t L a k e s p r o d u c tio n , v a r y in g fro m a low o f 11 p e r c e n t i n 1968, t o a h ig h o f 61 p e r o e n t i n 1982. se e m s t h a t c a t f i s h From t h e s e d a t a , it p r o d u c ti o n i n M ich ig an h a s in o r e a s e d i t s s h a r e w ith r e s p e c t t o U .S . a s w e ll a s G re a t L akes c a t f i s h p ro d u c tio n , e s p e c i a ll y fro m 1 9 7 3 t o 1982 w h ere M ich ig an o a t f i s h p r o d u c tio n d o m in ated b o th U .S . and G re a t L akes c a t f i s h p r o d u c tio n . The a n n u a l c u r r e n t p r i c e o f M ich ig an c a t f i s h h a s in o r e a s e d s t e a d i l y from 22 c e n t s p e r p o u n d i n 1960 t o 43 c e n t s i n a b o u t 95 p e r c e n t o v e r t h e p e r i o d 1982, an in c r e a s e o f ( a s p r e s e n t e d i n T a b le I V - 3 ) . i n d i c a t e s t h a t a s th e q u a n t ity o f o a t f i s h la n d in g s in o r e a s e d , c u rre n t p ric e s o f c a tf is h a ls o in o re a s e d . c u r r e n t p r i c e s d id n o t r e s p o n d t o T h is th e T h is s u g g e s ts t h a t an n u a l th e q u a n tity o f c a t f i s h h a r v e s te d . H o w e v er, r e a l p r i c e s seem r e s p o n s iv e t o th e q u a n t i t y o f c a t f i s h la n d e d . A nnual r e e d p r i c e s d e c r e a s e d from 72 c e n t s p e r pound i n 1960 t o 43 c e n t s in 1 9 8 2 , a d e c r e a s e o f a b o u t 40 p e r c e n t . c e n t s o c c u r r e d i n 1966. d u rin g 196 0 - 1 9 8 2 The h ig h e s t r e a l p r i c e o f 92 The a n n u a l g ro w th r a t e w as a b o u t of o a tfis h p ro d u c tio n 2 .9 p e rc e n t w h ile th e o u r r e n t p r ic e s in c r e a s e d by 3 .1 p e r c e n t p e r y e a r . On th e o t h e r h a n d , t h e r e a l p r i c e s d e c r e a s e d by 2 .3 p e r c e n t a n n u a lly . The tr e n d o f a n n u a l c u r r e n t and r e a l p r i c e s , a s w e ll a s p r o d u c tio n a r e p r e s e n te d i n F ig u r e IV -7 . T he f i g u r e sh o w s t h a t e v e n th o u g h a n n u a l p r o d u c tio n f l u c t u a t e s c o n s id e r a b ly , th e a n n u a l c u r r e n t p r i c e s seem more s t a b l e an d i n c r e a s e m o d e s t l y . r e a l p ric e s f lu c tu a te s lig h tly A nnual an d move i n r e s p o n s e t o th e l e v e l o f 86 T a b le IV -9 . C a t f i s h P r o d u c tio n from M ich ig an G re a t L akes and I t s R e l a ti o n s h i p t o U .S . and t h e Whole G re a t L akes P r o d u c tio n 1960-1982 Y ear M ich ig an P ro d u c­ tio n (in 1000 l b s . ) 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 370 325 228 213 201 196 198 161 123 143 227 339 265 336 281 297 416 456 458 484 515 561 692 a) U .S. P ro d u c­ tio n ( in 1000 l b s . ) 1,901 1 ,8 6 9 1 ,3 0 5 1 ,2 6 6 1 ,3 1 8 1 ,1 3 7 910 788 873 860 756 973 940 583 587 560 644 715 665 729 772 939 920 M ich ig an P r o d u c tio n as a % of Whole a ) US P roduc­ G .L. ( i n 1000 l b s . ) t i o n ( i n %) 2 ,2 2 4 2 ,1 1 3 1 ,6 1 9 1 ,5 6 6 1 ,6 0 5 1,3 8 0 1,1 8 3 1,03 8 1 ,1 2 9 1 ,0 8 0 860 1 ,1 2 9 1,096 763 774 825 780 859 857 943 961 1,196 1,1 3 2 19 17 18 17 18 17 22 20 *14 17 30 35 28 58 49 53 65 64 69 66 67 60 75 M ich ig an P r o d u c tio n as a % of t h e Whole G.L. P ro d u c­ t i o n ( i n %) 17 15 14 14 13 14 17 15 11 13 26 30 24 44 36 36 53 53 53 50 54 47 61 US p r o d u c tio n p lu s O n ta rio (C anada) p r o d u c tio n . S o u rc e s : F is h e r y D iv is io n , M ich ig an D ep t, o f N a tu r a l R e s o u rc e s . N a tio n a l O ceanio and A tm o sp h eric A d m in is tr a tio n . G re a t L ak es F is h e r y L a b o r a to r y , Ann A rb o r. M in is tr y o f N a tu r a l R e s o u rc e s , O n ta rio P r o v in c e , C anada. C a lc u la te d from d a t a s u p p lie d by s o u r c e s ab o v e f o r M ic h ig a n 's s h a r e o f p r o d u c tio n fro m US and GL. CATFISH Q u a n tity ^ . ... Price ($) (million pounds) 1. 0 - 0 .7 0.8 . 0 .6 - - 0 .5 0.6 . - 0 .4 • - 0 .3 0 .4 - - 0.2 - 0.1 0.2 - 1960 62 F ig u r e IV -7 . 64 66 68 70 72 74 76 78 80 82 A nnual M ichigan C a t f i s h L andings, A nnual C u r r e n t P r i c e , and A nnual R eal P r i c e 1960 - 1982 __________ p ro d u c tio n --------------- re a l p ric e .............. c u rre n t p ric e YEAR 88 o a tfis h p ro d u c tio n . F ig u re IV - 8 is a ls o p re s e n te d to sh o w th e r e l a t i o n s h i p b etw ee n r e a l p r i c e s and t h e q u a n t i t y o f c a t f i s h la n d in g s i n M io h ig an . Pound n e t , f y k e , hoop n e t , s e i n e , s e t h o o k s, 2" g i l l n e t , 7 -9 " g i l l n e t , s m a ll mesh t r a p , and l a r g e m esh t r a p h a r v e s t c a t f i s h from M ich ig an w a t e r s . a r e am ong t h e g e a r u s e d t o H owever, o n ly t h e m ain g e a r s u c h a s s e t h o o k s, s e i n e , s m a ll mesh t r a p , and l a r g e mesh t r a p a r e p r e s e n t e d i n T a b le I V - 10. T he q u a n t i t y o f c a t f i s h h a r v e s te d u s in g s e t hooks h a s b een q u i t e s t a b l e o v e r t h e p e r io d , and v a r i e d from 172 th o u s a n d p o u n d s in 1960 t o 184 th o u s a n d pounds i n 1982. D u rin g t h e m id - 1 9 6 0 's h o w ev er, th e q u a n t i t y o f c a t f i s h c a u g h t u s in g t h i s g e a r b eg an t o d e o l in e t o a low o f 63 th o u s a n d pounds i n 1970. h a rv e s te d s t a r t e d A f te r t h i s d e c l i n e th e am ount o f c a t f i s h to in c re a s e g ra d u a lly . T he q u a n t i t y o f o a t f i s h h a r v e s t e d u s i n g s e i n e n e t f l u c t u a t e d som ew hat, from a b o u t 82 th o u s a n d pounds i n 1960 t o 60 th o u s a n d p o u n d s i n 1982. Among t h e t y p e s o f g e a r show n i n T a b le IV -1 0 , t h e s m a ll mesh t r a p n e t i s th e m o st d o m in an t g e a r used i n h a rv e s tin g c a t f i s h . The q u a n t i t y o f c a t f i s h c a u g h t w ith t h i s g e a r h a s i n o r e a s e d s i g n i f i c a n t l y from a b o u t 103 th o u s a n d pounds i n 1960 t o 429 th o u s a n d p ounds i n 1982, a n in c r e a s e o f more th a n t h r e e f o l d o v e r th e p e rio d . T he s h a r e o f o a t f i s h h a r v e s te d w ith a s m a ll mesh t r a p n e t h a s in c r e a s e d from 28 p e r c e n t o f th e t o t a l h a r v e s t i n 1960 t o 62 p e r c e n t i n 1982. A lew iv es (A lo sa p s eu d o h are rm u s) The q u a n t i t y o f a le w i f e la n d in g s fro m M ic h ig a n 's G re a t L akes w a te r s has f lu c tu a te d c o n s i d e r a b l y fr o m 1960 t o 1982. The p r o d u c t i o n h a s R eal P r ic e ($) 1.0 - •66 •62 • .7 3 69* 72* • 78 0.2 - 1 F ig u r e IV -8 . 2 3 4 5 R eal P r i c e an d Q u a n tity o f C a t f is h L an d in g s i n M ichigan 1960 - 1982 6 7 QUANTITY ( m illio n pounds) T ab le IV -10. Year 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 S o u rce: C atch and E f f o r t f o r D if f e r e n t Types o f G ear, and C atch p e r U n it o f E f f o r t (CPE) f o r S tan d a rd Gear f o r C a tf is h on M ichigan G re a t Lakes W ater 1960-1982 S e t Hooks C atch E ffo rt 172,182 172,243 104,732 104,397 80,189 63,537 63,276 61,577 47,982 60,589 63,861 77,539 71,209 90,013 96,219 94,569 112,643 157,002 149,454 133,106 150,412 139,952 183,995 2,154 2,374 2,073 1,776 1,429 1,233 1,069 887 674 927 879 808 570 780 634 564 677 887 776 723 955 794 916 S ein e C atch E ffo rt 81,707 78,531 54,247 35,269 26,287 34,194 26,533 17i 084 12,698 9,704 7,5 6 5 56,451 67,115 80,250 45,173 71,106 105,178 119,455 101,010 89,984 80,515 95,023 59,651 719 620 572 367 213 285 193 198 176 107 100 407 471 480 281 307 360 407 354 337 320 307 293 Sm. Mesh T rap C atch E ffo rt 103,524 66,925 65,351 69,410 89,123 93,630 104,299 75,297 62,073 65,173 152,952 202,780 112,435 164,562 137,780 130,899 197,757 178,338 205,552 260,061 278,194 310,998 429,395 8,6 9 2 9 ,2 9 8 7,717 7,636 7,0 4 4 7,7 8 7 6 ,7 6 9 5 ,4 9 7 4,517 4 ,1 6 2 3,4 7 8 4 ,2 9 9 4,*166 5,3 3 4 4,9 5 8 5,3 9 5 5,3 2 8 5,2 6 5 4 ,9 0 5 4 ,4 0 9 3,7 6 4 4,8 0 6 5,0 5 9 Lg. Mesh T rap C atch E ffo rt 2 41 63 0 0 0 0 0 0 61 0 265 18 339 81 39 7 2 1204 713 968 2313 2847 7 10 6 0 0 0 0 0 0 12 0 32 18 50 8 12 6 11 98 100 108 231 474 C a lc u la te d from raw d a ta s u p p lie d by F is h e ry D iv is io n , M ichigan D ept, o f N a tu ra l R eso u rces f o r 1960-1970 F is h e ry D iv is io n , M ichigan D epartm ent o f N a tu ra l R eso u rces f o r 1971-1982 CPE f o r Sm. Mesh T rap 11.91 7 .2 0 8.47 9 .0 9 12.65 12.02 15.41 13.70 13.74 15.66 43.98 47.17 26.99 30.85 27 .7 9 24.26 37.12 33.87 41.91 58.98 73.91 64.71 84.88 91 i n c r e a s e d from a b o u t 1 ,6 9 0 th o u s a n d p o u n d s i n 1 3»3 7 0 th o u s a n d p o u n d s i n 1967* an i n c r e a s e a p p ro x im a te ly se v e n tim e s t h a t o f 1 9 6 0 's p r o d u c tio n . c o n tin u o u s ly to i t s 1960 t o a p e a k l e v e l o f A f te r 1967, th e p ro d u c tio n began to lo w e s t l e v e l o f 605 th o u s a n d pounds i n d e c r e a s e o f 95 p e r c e n t fro m 1967 l a n d i n g s . d ro p 1980, a P r o d u c t i o n w as a t 1 ,6 9 4 th o u s a n d pounds i n 1982 a s c a n b e s e e n i n T a b le IV -11. M ic h ig a n 's s h a r e o f U .S . a l e w i f e l a n d in g s a l s o d e c r e a s e d s i g n i f i c a n t l y , from a h ig h o f 71 p e rc e n t in 1 9 6 0 t o a lo w o f 4 p e r o e n t i n 1980, w ith 8 p e r c e n t i n 1982. The a v e ra g e d s h a r e o v e r th e 23 y e a r p e r io d w as a b o u t 16 p e r o e n t ( T a b l e IV -2 ). The d e c l i n e o f M ich ig an a le w iv e s h a r v e s te d a f t e r 1967 m ig h t have b een c o n t r i b u t e d t o by t h e m a ss iv e d ie o f f o f a le w iv e s i n L ake M ic h ig a n in 1 9 6 7 w h ic h p r o b a b l y w as c a u s e d h e m o rrh a g in g (Brow n, 1 9 6 8 ). h a rv e s te d w h ic h u n m a rk e ta b le . w e re by s a p r o l e g n i a i n f e c t i o n an d Due t o c o n ta m in a tio n , m ost o f t h e a l e w i v e s p rim a rily fo r a n im a l c o n s u m p tio n , w e re T h is , in e f f e c t , h a s f u r t h e r a g g r a v a te d th e d e c l in e o f M ichigan a le w i f e l a n d i n g s . 1 S in c e a l e w i v e s a r e n o t h a r v e s t e d i n C an ad ian G re a t L akes w a te r s , a l l a le w if e la n d in g s fro m th e G re a t L akes a re o o m in g f r o m U .S . ju ris d ic tio n s . A nnual c u rre n t p rio e s of a le w iv e s w e re r e l a t i v e l y s ta b le , f l u c t u a t i n g b etw een one c e n t and two c e n t s o v e r a 23 y e a r p e r i o d . It seem s t h a t an n u al c u r r e n t p r i c e s a r e n o t v e r y r e s p o n s iv e t o th e q u a n t i t y o f a le w i f e la n d in g s . A nnual r e a l p r i c e s f l u c t u a t e d an d v a r i e d fro m a h i g h o f 7 c e n t s p e r pound i n 1960 t o a low o f 2 c e n t s d u r in g 1970-1973; 1 9 7 5 - 1 9 7 7 t a n d 1 9 8 0 - 1 9 8 2 , a d e c r e a s e o f a b o u t 71 p e r o e n t o v e r t h e 1P e r s o n a l co m m u n icatio n w ith F is h e r y D iv is io n , M ich ig an D ep artm ent o f N a tu r a l R e s o u rc e s . 92 T a b le IV -1 1 . T ear 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1071 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 N o te: S o u rc e s : A le w ife P r o d u c tio n from M ich ig an G re a t L ak es and I t s S h a re o f U .S . P r o d u c tio n 1960-1982 M ich ig an P r o d u c tio n ( i n 000 l b s . ) 1,6 9 0 1 ,0 9 4 1 ,3 9 9 1 ,5 8 0 3 ,3 3 1 3 ,1 4 0 6 ,4 4 3 1 3 ,3 7 0 9 ,0 3 8 7 ,4 9 0 5,981 4 ,3 6 8 5,1 9 6 5 ,2 5 4 5 ,7 7 0 3 ,6 7 8 4,6 2 1 4 ,4 7 6 3 ,4 5 5 2 ,5 9 9 605 1 ,0 8 2 1 ,6 9 4 U .S . P r o d u c tio n ( i n 000 l b s . ) 2,381 3,211 4 ,7 4 6 5 ,3 9 8 1 1 ,7 4 5 1 4 ,0 0 7 2 9 ,0 0 8 4 1 ,8 9 5 2 7 ,1 9 4 2 9 ,2 4 8 3 3 ,4 6 1 3 0 ,4 1 8 3 1 ,0 3 3 3 6 ,7 0 6 4 5 ,0 9 5 3 5 ,2 1 6 3 9 ,2 1 2 4 8 ,4 0 6 4 3 ,8 7 9 2 7 ,5 0 3 1 3 ,5 1 2 1 9 ,3 2 4 2 2 ,1 5 9 M ich ig an S h a re o f U .S . P r o d u c tio n ( i n p e r o e n t) 71 34 29 29 28 22 22 32 33 26 18. 14 17 14 13 10 12 9 8 9 4 6 8 T h e r e i s no a l e w i f e p ro d u ced from C an ad ian G re a t L akes w a te r s . The w hole p r o d u c tio n comes from th e U .S . a r e a . F is h e r y d i v i s i o n , M ich ig an D ep artm en t o f N a tu r a l R e s o u rc e s . N a tio n a l O c e a n ic and A tm o sp h eric A d m in is tr a tio n . G r e a t L akes F is h e r y L a b o r a to r y , Ann A rb o r. C a lc u la te d from d a t a s u p p lie d by s o u r c e s ab o v e f o r M ic h ig a n 's s h a r e o f p r o d u c tio n from U .S . and GL. 93 p e r io d . (S ee T a b le I V - 3 ) . The q u a n t i t y o f a le w iv e s p r o d u c ti o n i n 1982 w as o n l y f o u r t h o u s a n d p o u n d s h i g h e r t h a n th e l e v e l o f p r o d u o tio n i n 1960. On th e a v e r a g e , d u r in g t h i s p e r io d , t h e r e w as a lm o s t n o i n c r e a s e i n a n n u a l a le w iv e s p r o d u o tio n , and t h e an n u a l c u r r e n t p r i c e a l s o d id n o t change o v e r t h e p e r i o d . v a lu e , A lth o u g h v e r y s m a l l , i n te rm s o f a b s o lu t e t h e a n n u a l r e a l p r i c e s h a v e d e c r e a s e d by a n a v e r a g e o f 5 .5 p e r o e n t o v e r th e p e r i o d . P ro d u o tio n t r e n d , a n n u a l c u r r e n t and r e a l p r i c e s o f a l e w i v e s o v e r 1960-1982 p e r io d a r e p r e s e n te d i n F ig u r e IV -9 , w h ile th e r e l a t i o n s h i p b etw ee n a n n u a l r e a l p r i c e s a n d t h e q u a n t i t y o f a le w iv e s l a n d in g s i s p r e s e n te d i n F ig u r e XV-10. T h ere a r e many ty p e s o f g e a r u se 'd t o h a r v e s t a l e w i v e s ; h o w e v e r, o n l y f o u r t y p e s o f g e a r c o n s i d e r e d a s t h e m ain g e a r , u se d t o c a tc h a l a r g e p o r t i o n o f t h i s s p e c i e s , a r e p r e s e n te d i n T a b le IV -1 2 . The p o u n d n e t i s th e m ost d o m in an t g e a r u s e d from 1960 t o th e p r e s e n t . The u s e o f th e o t t e r t r a w l h a s d e c r e a s e d d r a s t i c a l l y , e s p e c i a l l y in c h a fte r 1974* Two and 4- 6 " g i l l n e ts d id n o t have a s i g n i f i c a n t c a to h o v e r th e p e r io d . ALEWIFE Q u a n tity (m illio n pounds) P r ic e « 0 7 6 5 4 •— • 3 2 • • 1 0 1960 62 F ig u r e IV -9 . 64 66 68 70 72 74 76 78 80 82 A nnual M ichigan A le w ife L an d in g s, A nnual C u r re n t P r i c e , and A nnual R eal P r i c e 1960 - 1982 p ro d u c tio n r e a l p ric e c u rre n t p ric e YEAR R eal P r ic e (£) 7 6 65 64 5 4 3 2 61 80 81 62 82 ..77 ?672..73 73 1 0 (million pounds) F ig u r e IV -10. R e a l P r i c e an d Q u a n tity o f A le w ife Landings i n M ichigan 1960 - 1982 T able IV -12. C atch and E f f o r t f o r D if f e r e n t Types o f G ear, and C atch p e r U n it o f E f f o r t (CPE) f o r S ta n d a rd Gear f o r A lew ives I n M ichigan G reat Lakes V a te r 1960-1982 Year 2" G i l l N et C atch E ffo rt 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 15,057 2 ,2 3 0 5,047 1,240 2 ,9 2 4 616 5,154 81 201 2 ,1 2 9 1,150 5,5 0 5 599 6,0 1 9 4,365 3,3 4 9 4,7 5 2 3 600 41 16 10 733 S o u rc e s: 0 324 0 121 215 63 122 46 132 319 863 895 412 623 604 888 1157 26 150 187 35 80 502 Found Net Catch E ffo rt 1,585,146 723,940 1 ,0 6 9 ,6 3 2 1 ,0 3 0 ,9 6 5 1 ,0 4 8 ,7 0 5 700,800 3 ,0 4 6 ,6 2 0 9,8 56,421 4 ,9 1 4 ,2 5 5 5 ,7 4 0 ,1 3 2 4 ,0 8 5 ,2 8 0 3 ,7 4 4 ,7 0 0 5 ,1 3 3 ,6 6 0 4 ,7 5 5 ,4 5 0 5 ,0 2 4 ,8 0 0 3 ,6 5 2 ,3 8 0 4 ,5 8 9 ,8 7 0 4 ,4 7 2 ,8 6 5 3 ,4 5 0 ,3 1 3 2 ,5 8 6 ,8 0 0 604,500 1 ,0 8 2 ,2 3 0 1,687,506 0 0 0 249 232 96 557 2416 848 1066 944 611 547 460 663 441 745 912 687 531 122 164 445 4-6 " G i l l Net C atch E f f o r t 85 30 1 68 37 80 41 15 1 1647 1458 720 2544 4725 861 5474 4624 2585 3935 11960 350 0 0 0 0 0 6 2 12 50 11 6 880 1630 976 4102 4732 1475 3222 2722 990 1561 1771 396 0 0 O tte r Traw l Catch E ffo rt 44,800 3 ,5 4 ,5 1 0 319,945 402,986 2 ,2 7 8 ,4 1 5 2 ,4 3 8 ,6 9 0 3 ,3 9 0 ,7 2 2 3 ,5 1 3 ,1 7 5 3 ,8 4 5 ,3 3 3 1 ,7 3 8 ,6 0 0 1 ,8 9 3 ,5 1 0 617,325 59,227 240,955 739,460 17,040 21,540 275 0 0 0 0 4 ,6 0 0 0 815 1,365 7,806 1,470 12,203 14,578 1,355 1,370 510 392 61 53 99 134 75 35 5 0 0 0 0 7 C a lc u la te d from raw d a ta s u p p lie d by F is h e r y D iv is io n , M ichigan D ept, o f N a tu ra l R eso u rces f o r 1960-1970. F is h e ry D iv is io n , M ichigan D epartm ent o f N a tu ra l R eso u rces, f o r 1971-1982. CPE f o r Pound Net 0 0 0 4 ,1 4 0 .4 4 ,5 2 0 .3 7 ,3 0 0 .0 5 ,4 6 9 .7 4 ,0 7 9 .6 5 ,7 9 5 .1 5 ,3 8 4 .7 4 ,3 2 7 .6 6 ,1 2 8 .8 9*385.1 1 0 ,3 3 7 .9 7 ,5 7 8 .9 8 ,2 8 2 .0 6 ,1 6 0 .9 4 ,9 0 4 .5 5 ,0 2 2 .3 4 ,8 7 1 .6 4 ,9 5 4 .9 6 ,5 9 9 .0 3 ,7 9 2 .1 97 The annual growth rate of production, ourrent prices, and real prices of whltefish, chubs, yellow perch, catfish, and alewives are summarized In Table IV-13. T a b le IV -1 3 . S p e c ie s W h lte f is h Chubs Y ellow P erch C a tfis h A lew iv es A nnual Growth R a te o f P r o d u c tio n , C u r r e n t P r i c e s , and R e a l P r i c e s o f S e v e r a l M ich ig an Com m ercial F is h S p e c ie s 1960-1982 P ro d u o tio n C u rren t P ric e s ( i n P e r c e n t) 1 2 .4 - 9 .2 - 9 .8 2 .9 0 .0 .6 7 .1 9 .5 3 .1 0 .0 R eal P r i c e s - 4 .7 1 .5 3 .7 - 2 .3 - 5 .5 * N e g a tiv e s i g n s i n d i c a t e t h a t p r o d u c t i o n / p r i c e s d e o r e a s e d . I n T a b le IV -1 4 , a n n u a l U .S . o u r r e n t and r e a l p r i c e s o f f i s h s p e c i e s in c lu d e d i n t h i s s tu d y a r e p r e s e n te d . T able IV -14. Year Annual US C u rre n t and R eal ( p e r pound) P r ic e s o f S e v e ra l Commercial F is h S p e c ie s from US G re a t Lakes H a te rs (1960-1982) W h lte fis h C u rre n t Real 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 .57 .5 2 .53 .51 .59 .5 0 .5 0 .57 .6 0 .60 .56 .44 .50 .55 .6 7 .67 •71 .74 .77 .85 .82 .74 .6 7 S o u rc e s: * 1.86 1.68 1.69 1.61 1.84 1.5 3 1.49 1 .6 5 1.67 1.58 1.39 1.05 1.15 1 .2 0 1.31 1 .2 0 1.20 1.18 1.15 1.13 .96 .79 .67 _. Chubs C u rre n t Real .1 5 .13 .1 2 .14 .16 .17 .19 .15 .15 .15 .1 8 .17 .24 .38 .5 0 .5 7 .61 .52 .58 .73 .76 .73 .6 5 .4 3 .4 2 .3 8 .44 .5 0 .5 2 .5 7 .4 3 .4 2 .3 9 .4 5 .4 0 .5 5 .8 3 .9 8 1.02 1.03 .83 .86 .9 7 .89 .77 .6 5 P erch C u rre n t .11 .13 .0 9 .09 .17 .18 .1 2 .1 2 .1 2 .14 .1 8 .13 .3 4 .38 .3 8 .53 .7 9 .61 .68 .88 .5 2 1.02 1.26 R eal .3 6 .4 2 .2 9 .2 8 .53 .5 5 .3 6 .35 .3 3 .37 .45 .31 .7 9 .8 3 .74 .95 1.34 .9 7 1.01 1.17 .61 1.08 1.26 C a tf is h C u rre n t R eal .21 .23 .22 .25 .27 .29 .26 .30 .28 .34 .41 .38 .33 .38 .40 .46 .45 .45 .4 5 .43 .45 .45 .43 .68 .7 4 .7 3 .79 .84 .8 9 .77 .87 .7 8 .89 .9 8 .88 .7 6 .83 .7 8 .82 .7 6 .7 2 .67 .5 7 .53 .48 .43 A lew ives C u rre n t ]Real .0 2 .01 .01 .02 .0 2 .02 .0 2 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .0 2 .02 .0 2 .0 2 .02 .0 2 .07 .03 .03 .06 .06 .06 .06 .03 .0 3 .03 .0 2 .02 .0 2 .0 2 .0 2 .0 2 .0 2 .03 .03 .03 .0 2 .02 .02 G re a t Lakes F is h e r y L a b o ra to ry , Ann A rbor. N a tio n a l O ceanic and A tm ospheric A d m in is tra tio n . N a tio n a l M arine F i s h e r i e s . R eal P r ic e s a r e c a lc u la te d from d a ta s u p p lie d by th e same s o u rc e s above. CHAPTER V ESTIMATION OF BIOECONOMIC MODEL PARAMETERS The e s t i m a t e o f b io e co n o m ic p a ra m e te rs u s in g t h e l i n e a r i z e d s u r p l u s p ro d u o tio n m o d e l, w hich i s d e r iv e d from t h e m odel d e v e lo p e d by S c h a e f e r , i s one te c h n iq u e t h a t i s e m p lo y ed u t i l i z e i n f o r m a t i o n fr o m y i e l d a n d e f f o r t d a ta . In th is s t u d y a n n u a l d a t a f o r c a t c h p e r u n i t o f e f f o r t (CPE) and t o t a l e f f o r t (E) a r e b a s e d on s ta n d a r d g e a r u se d f o r e a c h f i s h s p e c ie s fro m 1 9 6 0 - 1 9 8 2 , w h ic h a r e g iv e n i n T a b le s V -1; V -2 ; V -3; V -4 ; and V -5 . T he f o r m u l a w h ic h h a s b e e n u s e d t o c o n v e rt c a tc h and e ffo rt to a s ta n d a r d g e a r h a s b e e n d is c u s s e d i n C h a p te r I I I . T he CPE f o r w h i t e f i s h u s i n g e i t h e r a l a r g e m esh t r a p g i l l n e t h a s i n c r e a s e d c o n s id e r a b ly from 1 9 6 0 -1 9 8 2 . net or a The c a t c h p e r u n i t o f e f f o r t f o r l a r g e mesh t r a p n e t s h a s I n c r e a s e d fro m a b o u t 133 p o u n d s in 19 6 0 t o 290 p o u n d s i n 1 9 8 2 , a n i n c r e a s e o f more th a n one f o l d . A s i m i l a r t r e n d a l s o o c c u r r e d w i t h g i l l n e t s , w h e re CPE i n c r e a s e d fro m ab o u t 10 pounds i n 1960 t o 84 pounds i n 19 8 2 , an i n o r e a s e o f ab o u t se v e n fo ld . T h is in o r e a s e m ig h t b e c a u s e d b y b i o l o g i c a l a n d t e c h n o l o g i c a l e f f e c t s a s m e n tio n e d by G h a n b a ri (1 9 7 7 )* th e CPE f l u c t u a t e s a s f i s h s to c k f lu c t u a te s . i n c r e a s e t h e n t h e CPE w i l l i n o r e a s e , e f f e c ts in c lu d e in f o r m a tio n . im p ro v e d The b i o l o g i c a l a s p e c t i s t h a t gear When t h e f i s h s to c k s an d v i s e v e r s a . T e c h n o lo g ic a l e ffic ie n c y and im p ro v e d w e a th e r F o r i n s t a n c e , th e i n t r o d u c t i o n o f m o n o filam en t n e t i n th e l a t e 1 9 5 0 's an d e a r l y 1 9 6 0 's , i n c r e a s e d e f f i c i e n c y o v e r th e u s e o f n y lo n n e ts . T h i s n e t a l s o a llo w s f o r f i s h i n g i n d e e p e r w a te r . 99 The i n c r e a s e 100 Table V-1. Total Catoh, Catoh per Unit of Effort, and Total Effort of Whltefish from Michigan's Great Lakes Waters 1960-1982 (Using Large Mesh Trap Nets and Gillnets as Standard Gear) L a rg e Mesh T rap C a tc h /E ffo rt (CPE) T o ta l E ffo rt 4 -6 " G i l l N et C a t o h /E f f o r t (CPE) T o ta l E ffo rt Y ear T o ta l C atch (In lb .) 1960 5 5 0 ,7 0 0 1 3 2 .7 0 4 ,1 4 9 .9 6 1 0 .2 0 5 3 ,9 9 0 .2 1961 9 3 8 ,9 0 0 1 2 7 .6 0 7 ,3 5 8 .1 5 1 1 .9 5 7 8 ,5 6 9 .0 1962 8 0 9 ,3 0 0 1 1 3 .6 0 7 ,1 2 4 .1 2 1 3 .0 5 6 2 ,0 1 5 .3 1963 7 1 2 ,1 0 0 5 4 .8 7 1 4 ,7 4 9 .4 1 1 6 .3 5 4 3 ,5 5 3 .5 1964 1 ,0 9 7 ,8 0 0 99.81 1 0 ,9 9 8 .9 0 1 4 .7 3 7 4 ,5 2 8 .2 1965 1 ,3 9 3 ,1 0 0 7 8 .2 1 1 7 ,8 1 2 .3 0 1 5 .4 2 9 0 ,3 4 3 .7 1966 1 ,7 4 4 ,2 0 0 1 5 9 .1 5 1 0 ,9 5 9 .4 7 1 9 .9 7 8 7 ,3 4 1 .0 1967 1 ,3 9 8 ,6 0 0 1 5 0 .7 6 9 ,2 7 7 .0 0 1 8 .8 3 7 4 ,2 7 5 .1 1968 1 ,5 4 8 ,2 0 0 13 3 .7 2 1 1 ,5 7 7 .9 2 1 8 .7 3 8 2 ,6 5 8 .8 1969 2 ,0 2 0 ,3 0 0 1 5 4 .6 9 1 3 ,0 6 0 .3 1 2 3 .0 5 8 7 ,6 4 8 .6 1970 1 ,9 0 4 ,7 2 6 1 5 8 .1 5 1 2 ,0 4 3 .7 9 2 3 .2 6 8 1 ,8 8 8 .5 1971 2 ,9 8 5 ,1 4 1 2 0 6 .3 4 1 4 ,4 6 7 .1 0 3 5 .7 3 8 3 ,5 4 7 .2 1972 3 ,4 9 3 ,9 7 1 2 6 8 .3 4 1 3 ,0 2 0 .6 9 4 0 .2 4 8 6 ,8 2 8 .3 1973 3 ,4 5 0 ,5 1 5 2 0 9 .5 4 1 6 ,4 6 7 .0 9 4 3 .7 2 7 8 ,9 2 3 .0 1974 2 ,9 6 0 ,5 5 8 2 1 7 .7 2 1 3 ,5 9 8 .0 1 3 4 .0 1 8 7 ,0 4 9 .6 1975 2 ,9 5 4 ,0 2 9 2 4 1 .4 2 1 2 ,2 3 6 .0 6 3 3 .7 8 8 7 ,4 4 9 .1 1976 3 ,4 5 1 ,3 0 8 2 5 6 .9 2 1 3 ,4 3 3 .4 0 3 3 .9 9 1 0 1 ,5 3 8 .9 1977 2 ,9 1 5 ,7 6 5 2 2 3 .1 8 1 3 ,0 6 4 .6 3 3 8 .3 3 7 6 ,0 7 0 .0 1978 3 ,2 3 9 ,1 7 5 2 3 9 .8 5 1 3 ,5 0 5 .0 0 3 4 .7 6 9 3 ,1 8 6 .9 1979 3 ,4 1 2 ,4 4 2 2 3 2 .8 8 1 4 ,6 5 3 .2 2 3 3 .8 2 1 0 0 ,9 0 0 .1 1980 5 ,1 4 0 ,7 2 6 2 4 5 .0 4 2 0 ,9 7 9 .1 3 4 2 .3 0 1 2 1 ,5 3 0 .2 1981 6 ,7 9 7 ,1 6 6 2 9 8 .5 8 2 2 ,7 6 4 .9 7 5 6 .4 2 1 2 0 ,4 7 4 .4 1982 7 ,1 4 8 ,2 3 6 2 89 .9 1 2 4 ,6 5 6 .7 4 8 3 .7 3 8 5 ,3 7 2 .5 101 Table V-2. Total Catch, Catoh per Unit of Effort, and Total Effort of Chubs from Michigan's Great Lakes Haters 1960-1982 (Using 2 Inch Gillnets as Standard Gear) Y ear T o t a l C ato h (in l b . ) C a tc h /E ffo rt (CPE) 1960 6 ,8 1 2 ,3 0 0 3 9 .6 5 1 7 1 ,8 1 0 .8 1961 6 ,4 9 3 ,7 0 0 4 5 .7 7 1 4 1 ,8 7 6 .8 1962 6 ,3 3 1 ,0 0 0 4 2 .8 6 1 4 7 ,7 1 3 .5 1963 4 ,8 9 0 ,6 0 0 3 9 .3 0 1 2 4 ,4 4 2 .7 1964 3 ,0 1 0 ,1 0 0 4 7 .0 3 6 4 ,0 0 3 .8 1965 5 ,2 9 6 ,3 0 0 5 4 .4 3 9 7 ,3 0 4 .8 1966 3 ,9 0 2 ,5 0 0 5 7 .8 7 6 7 ,4 3 6 .6 1967 4 ,7 9 2 ,9 0 0 7 0 .2 8 6 8 ,1 9 7 .2 1968 3 ,7 1 8 ,5 0 0 8 6 .7 1 4 2 ,8 8 4 .3 1969 3 ,4 3 9 ,0 0 0 1 2 7 .1 7 2 7 ,0 4 2 .5 1970 4 ,6 7 3 ,9 6 8 1 2 8 .2 0 3 6 ,4 5 8 .4 1971 3 ,1 9 9 ,5 8 3 9 9 .6 6 3 2 ,1 0 5 .0 1972 3 ,5 0 0 ,8 9 9 8 2 .1 6 4 2 ,6 1 0 .7 1973 3 ,0 8 7 ,9 4 9 6 7 .6 5 4 5 ,6 4 6 .0 1974 2 ,4 2 8 ,2 5 5 6 3 .2 7 3 8 ,3 7 9 .2 1975 1 ,5 3 9 ,3 5 5 6 0 .4 7 2 5 ,4 5 6 .5 1976 1 ,0 7 1 ,4 5 9 6 0 .3 7 1 7 ,7 4 8 .2 1977 843,741 69 .4 1 1 2 ,1 5 5 .9 1978 8 1 3 ,8 5 9 6 4 .8 3 . 1 2 ,5 5 3 .7 1979 8 0 5 ,4 4 7 67 .4 1 1 1 ,9 4 8 .5 1980 7 7 3 ,1 9 2 6 6 .5 7 1 1 ,6 1 4 .7 1981 7 9 7 ,2 2 8 5 8 .3 0 1 3 ,6 7 4 .6 1982 8 1 0 ,9 8 0 64.81 1 2 ,5 1 3 .2 ' T o ta l E f f o r t 102 Table V-3. Total Catoh, Catoh per Unit of Effort, and Total Effort of Yellow Perch from Michigan's Great Lakes Waters 1960-1982 (Using Small Mesh Trap Nets as Standard Gear) Y ear T o ta l C atoh (in l b . ) C a t c h /E f f o r t (CEE) 1960 1 ,9 2 1 ,9 0 0 2 1 .9 9 8 7 ,3 9 8 .8 1961 2 ,2 3 3 ,9 0 0 5 3 .6 3 4 1 ,6 5 3 .9 1962 1 ,5 0 4 ,8 0 0 2 0 .2 6 7 4 ,2 7 4 .4 1963 1 ,6 7 2 ,4 0 0 2 3 .5 9 7 0 ,8 9 4 .4 1964 3 ,2 5 6 ,2 0 0 2 3 .6 6 1 3 7 ,6 2 4 .7 1965 1 ,8 1 9 ,5 0 0 3 7 .0 8 4 9 ,0 6 9 .6 1966 1 ,8 4 9 ,5 0 0 81.51 2 2 ,6 9 0 .5 1967 1 ,7 0 3 ,2 0 0 8 2 .2 2 2 0 ,7 1 5 .2 1968 1 ,2 3 8 ,4 0 0 7 9 .1 4 1 5 ,6 4 8 .2 1969 1 ,1 6 4 ,3 0 0 6 3 .0 2 1 8 ,4 7 5 .1 1970 5 8 8 ,269 5 8 .6 6 1 0 ,0 2 8 .5 1971 5 9 3 ,9 6 0 3 2 .1 1 1 8 ,4 9 7 .7 1972 345,855- 4 9 .7 6 6 ,9 5 0 .5 1973 3 2 0 ,3 5 8 4 2 .6 9 7 ,5 0 4 .3 1974 2 3 1 ,7 9 7 3 5 .3 1 6 ,5 6 4 .6 1975 2 7 0 ,799 3 5 .2 1 7 ,6 9 1 .0 1976 323,071 44 .7 1 7 ,2 2 5 .9 1977 260,184 3 9 .5 8 6 ,5 7 3 .6 1978 1 6 8 ,879 2 9 .4 2 5 ,7 4 0 .3 1979 167,763 3 2 .6 0 5 ,1 4 6 .1 1980 2 4 9 ,1 7 5 3 9 .6 0 6 ,2 9 2 .3 1981 2 4 6 ,7 7 7 3 3 .5 9 7 ,3 4 6 .7 1982 1 9 6 ,844 2 6 .6 1 7 ,3 9 7 .4 T o ta l E f f o r t 103 Table V-4. Total Catoh, Catoh per Unit of Effort, and Total Effort of Catfish from Michigan's Great Lakes Waters 1960-1982 (Using Small Mesh Trap Nets as Standard Gear) Y ear T o ta l C ato h (In lb .) C a t o h /E f f o r t (CFE) 1960 3 7 0 ,1 0 0 1961 3 2 5 ,4 0 0 11.91 7 .2 0 3 1 ,0 7 4 .7 4 5 ,1 9 4 .4 1962 2 2 8 ,3 0 0 8 .4 7 2 6 ,9 5 4 .0 1963 2 1 2 ,5 0 0 9 .0 9 2 3 ,3 7 7 .3 1964 2 0 0 ,8 0 0 1 2 .6 5 1 5 ,8 7 3 .5 1965 195,500 1 2 .0 2 1 6 ,2 6 4 .6 1966 1 9 7 ,5 0 0 15.41 1 2 ,8 1 6 .4 1967 1 6 0 ,500 1 3 .7 0 1 1 ,7 1 5 .3 1968 12 3 ,4 0 0 1 3 .7 4 8 ,9 8 1 .1 1969 1 4 3 ,200 1 5 .6 6 9 ,1 4 4 .3 1970 2 2 7 ,2 7 9 4 3 .9 8 5 ,1 6 7 .8 1971 3 3 9 ,4 0 2 4 7 .1 7 7 ,1 9 5 .3 1972 2 6 5 ,1 3 6 2 6 .9 9 9 ,8 2 3 .5 1973 33 6 ,4 7 8 3 0 .8 5 1 0 ,9 0 6 .9 1974 2 8 1 ,4 8 2 2 7 .7 9 1 0 ,1 2 8 .9 1975 2 9 6 ,8 0 4 2 4 .2 6 1 2 ,2 3 4 .3 1976 415,606 3 7 .1 2 1 1 ,1 9 6 .3 1977 4 5 5 ,6 8 9 3 3 .8 7 1 3 ,4 5 4 .1 1978 4 5 8 ,0 2 7 41 .9 1 1 0 ,9 2 8 .8 1979 483,864. 5 8 .9 8 8 ,2 3 0 .9 1980 5 1 4 ,527 73 .9 1 6 ,9 6 1 .5 1981 560,953 6 4 .7 1 8 ,6 6 8 .7 1982 6 9 2 ,3 7 3 8 4 .8 8 8 ,1 5 7 .1 T o ta l E f f o r t 104 Table V-5. Total Catch, Catoh per Unit of Effort, and Total Effort of Alewives from Michigan's Great Lakes Waters 1960-1982 (Using Pound Nets as Standard Gear) Y ear T o t a l C ato h (in l b .) C a t o h /E f f o r t (CPE) 1960 1 ,6 9 0 ,2 0 0 0 0 1961 1 ,0 9 4 ,2 0 0 0 0 1962 1 ,3 9 8 ,6 0 0 0 0 1963 1 ,5 8 0 ,1 0 0 4 ,1 4 0 .4 3 8 1 .6 1964 3 ,3 3 1 ,2 0 0 4 ,5 2 0 .3 7 3 6 .9 1965 3 ,1 4 0 ,3 0 0 7 ,3 0 0 .0 4 3 0 .2 1966 6 ,4 4 2 ,7 0 0 5 ,4 6 9 .7 1 ,1 7 7 .9 1967 1 3 ,3 6 9 ,9 0 0 4 ,0 7 6 .6 3 ,2 7 9 .7 1968 9 ,0 3 7 ,7 0 0 5 ,7 9 5 .1 1 ,5 5 9 .5 1969 7 ,4 8 9 ,7 0 0 5 ,3 8 4 .7 1 ,3 9 0 .9 1970 5 ,9 8 1 ,4 1 8 4 ,3 2 7 .6 1 ,3 8 2 .2 1971 4 ,3 6 8 ,4 5 6 6 ,1 2 8 .8 7 1 2 .8 1972 5 ,1 9 6 ,1 6 0 9 ,3 8 5 .1 5 5 3 .7 1973 5 ,2 5 4 ,1 6 9 1 0 ,3 3 7 .9 5 0 8 .2 1974 5 ,7 6 9 ,6 7 6 7 ,5 7 8 .9 7 6 1 .3 1975 3 ,6 7 8 ,2 6 3 8 ,2 8 2 .0 44 4 .1 1976 4 ,6 2 0 ,7 8 6 6 ,1 6 0 .9 7 5 0 .0 1977 4 ,4 7 5 ,9 7 4 4 ,9 0 4 .5 91 2 .6 1978 3 ,4 5 4 ,8 9 8 5 ,0 2 2 .3 6 8 7 .9 1979 2 ,5 9 8 ,8 0 1 4 ,8 7 1 .6 5 3 3 .5 1980 6 0 4 ,8 6 6 4 ,9 5 4 .9 122.1 1981 1 ,0 8 2 ,3 9 0 6 ,5 9 9 .0 1 6 4 .0 1982 1 ,6 9 4 ,3 1 8 3 ,7 9 2 .1 4 4 6 .8 T o ta l E f f o r t 105 in CPE of whltefish is accompanied by an increase in the total catch over the period. D e s p ite a n n u a l f l u c t u a t i o n s in CPE o f o h u b s , p e r c e n t i n c r e a s e i n CPE from 1960 -1 9 8 2 . chubs i s t h e r e w as a s i x t y H owever, th e i n c r e a s e i n CPE o f n o t a s s o c i a t e d w ith an i n c r e a s e in t o t a l c a tc h , in s te a d th e t o t a l c a tc h d e c r e a s e d . The c a u s e s o f t h i s d e c r e a s e i n t o t a l c a t c h w e re d is c u s s e d i n C h a p te r IT . C a tc h p e r u n i t o f e f f o r t o f y e l l o w p e rc h d u rin g th e 1 9 6 0 -1 9 8 2 p e r io d h a s f l u c t u a t e d c o n s id e r a b ly , w ith th e peak l e v e l r e a c h e d i n 1967* In 1 9 8 2 , h o w e v e r , CPE o f y e l l o w p e r c e n t above 1960 l e v e l . in o re a s e d C atch p e r u n i t o f e f f o r t o f c a t f i s h h a s a l s o fro m 12 p o u n d s i n 1 9 6 0 t o 85 p o u n d s i n i n c r e a s e o v e r th e 23 y e a r p e r i o d . a ls o p e r c h i n o r e a s e d o n l y a b o u t tw e n t y a s s o c ia t e d w ith an in c r e a s e T he i n c r e a s e in 1982, a s ix fo ld i n CPE o f c a t f i s h to ta l c a tc h . is C atoh p e r u n i t o f e f f o r t o f a le w iv e s a l s o f l u c t u a t e d c o n s id e r a b ly from 4140 p o unds i n 1963 t o a p e a k l e v e l o f 10338 p o u n d s i n 1 9 7 3 , a n d t h e n d r o p p i n g t o 3792 pounds i n 1982. T o t a l c a t c h , CPE, and t o t a l e f f o r t , w hich a r e p r e s e n te d in to T a b le s V -1 b io eco n o m ic m o d el. s p e c ie s : V -5 , a r e u s e d to e s tim a te th e p a ra m e te rs o f th e T he e s t i m a t e s o f t h e s e w h lte fis h , chubs, p a ra m e te rs f o r e a c h f i s h y e l lo w p e r c h , c a t f i s h , and a le w iv e s from M ic h ig a n 's G re a t L ak es w a t e r s , a r e p r e s e n te d i n T a b le V -6. 106 T a b le V -6. S p e c ie s E s tim a te s o f th e P a r a m e te r s , k , K, and q f o r th e L o g i s t i c S u r p lu s P ro d u o tio n Model k K q W ith L arg e Mesh T ra p s W h lte f is h 0 .1 4 6 2 ,3 0 0 ,0 0 0 0 .5 1 x 10“ 5 W ith G i l l n e t s 0 .4 8 7 0 ,7 0 0 ,0 0 0 0 .6 7 x 10“ 5 W ith G i l l n e t s (1 9 7 1 -1 9 8 2 d a t a ) 1 7 ,2 5 0 ,0 0 0 0 .7 5 0 .5 7 x 10“ 5 W ith G i l l n e t s (1 9 7 1 -1 9 8 2 d a t a ) Chubs 0 .0 4 6 1 8 ,6 2 3 ,0 0 0 ,0 0 0 - 0 .3 3 x 10"5 W ith S m all Mesh T ra p s P e rc h 0 .1 4 3 4 ,8 0 0 ,0 0 0 - 0 .3 3 x 10"5 W ith S m all Mesh T ra p s C a tfis h 1 3 ,4 0 0 ,0 0 0 0 .3 0 - 0 .1 0 X 10"5 W ith Pound N e ts A le w ife 2 2 ,8 0 0 ,0 0 0 0 .0 0 5 0 .5 3 x 10“ 4 W ith Pound N e ts (1 9 7 1 -1 9 8 2 d a t a ) 4 6 9 ,8 5 4 ,0 0 0 0 .0 5 N o te : 0 .7 4 x 10"4 U n le s s s p e c i f i e d , a l l e s t i m a t e s a r e u s in g 1960-1982 d a t a . k = p o p u la tio n g ro w th r a t e K = e n v iro n m e n ta l c a r r y i n g c a p a c i t y q = c a to h a b ility c o e ffic ie n t The e s t i m a t e s o f k f o r w h l t e f i s h v a r y from 0 .1 4 w ith th e l a r g e mesh t r a p n e t s t o 0 .4 8 w ith g i l l n e t s and 0 .7 5 w ith g i l l n e t s u s in g 1 9 7 1 -1 9 8 2 d a t a . T he e s t i m a t e s o f c a r r y i n g c a p a c i t y , K, o b ta in e d by u s in g g i l l n e t s i s l a r g e r th a n th o s e o f u s in g l a r g e mesh t r a p s , h o w ev er, 197 1 -1 9 8 2 g i l l n e t 107 d a ta g iv e s th e s m a lle s t c a rry in g c a p a c ity . The c a t c h a b l l i t y c o e f f i c i e n t s a l s o v a r y fro m 0 .5 1 x 10“ ^ w ith l a r g e mesh t r a p s , 0 .6 7 x 10~5 a n d 0 .5 7 x 10” ^ w ith g i l l n e t s . The e s ti m a t e s o f k and q p a r a m e te rs f o r ch u b s seem r a t h e r c l o s e t o t h e e s t i m a t i o n s p e c ie s , c o e f f ic ie n ts o f o th e r h o w e v e r , t h e e s t i m a t e s o f o h u b s c a r r y i n g o a p a c ity i s q u i t e l a r g e ev e n a f t e r a d ju s tm e n t o f t h e 1 9 6 0 -1 9 8 2 d a t a t o 1 9 7 1 -1 9 8 2 d a t a . The e s ti m a t e o f k f o r y e llo w p e rc h i s 0 .1 4 and t h e c a t c h a b i l i t y r a t e , q , i s 0 . 3 3 x 10“ 5 . W ith t h e same s ta n d a r d g e a r , s m a ll mesh t r a p n e t s , th e c a t c h a b i l i t y c o e f f i c i e n t f o r o a t f i s h i s 0 .1 0 x 10” ^ and k i s 0 .3 0 . a le w iv e s w ith pound n e t s a s th e s t a n d a r d c o e ffic ie n t is 0 .5 3 x 1 0 " 1*; 1971-1982 d a t a , r e s p e c t i v e l y . g e a r, For th e c a tc h a b ility a n d 0 .7 4 x 10” 1* u s i n g 1 9 6 0 -1 9 8 2 an d The k p a r a m e te r s v a ry fro m 0 .0 0 5 t o 0 .0 5 by u s i n g d i f f e r e n t ti m e p e r i o d s . T he e s t i m a t e o f c a r r y i n g c a p a c i t y seem s t o be q u i t e d i f f e r e n t b etw een t h e s e tw o e s t i m a t e s , v a r y i n g fro m ab o u t 23 m i l l i o n pounds t o m ore th a n 400 m i l l i o n p ounds. The e s tim a te d p a r a m e te r s f o r e a c h f i s h s p e c i e s i n T a b l e V -6 a r e s u b s t i t u t e d i n t o e q u a tio n ( 3 .8 ) t o o b t a i n p r o d u o tio n f u n c t i o n s f o r eac h s p e c i e s a s show n b e lo w . T hese p ro d u c tio n f u n c tio n s r e p r e s e n t r e l a t i o n s h i p s b etw ee n e s ti m a t e d e q u i l i b r i u m y i e l d and e f f o r t . * HhttjrflaE L arg e Mesh T ra p s Y = 318E - 0.012E 2 ( 5 .1 ) G illn e ts Y = 474E - 0.006E 2 ( 5 .2 ) G i l l n e t s (1 9 7 1 -1 9 8 2 ) Y = 98.5E - 0.00074E 2 ( 5 .3 ) 115E - 0.0026E 2 ( 5 .4 ) P e rc h S m all Mesh T ra p s th e 108 Catfish S m all Mesh T ra p s Y s 134E - 0.0045E 2 ( 5 .5 ) A lS X lfS Pound N e ts Y = 1208E - 12.8E 2 ( 5 .6 ) Pound N e ts (1 9 7 1 -1 9 8 2 ) y = 34800E - 5 1 . 5E2 ( 5 .7 ) T h ese p r o d u c tio n f u n c t i o n s c a n be p l o t t e d i n t o i n F i g u r e s V - 1; V -2 ; V - 3 ; V -4 and V -5 . p a r a b o l a s a s show n (From e q u a t io n 5 . 2 j 5 .3 ; 5 .4 ; 5 . 5 ; and 5 . 7 ) . By c o m p a r in g F i g u r e 7 - 1 w i t h V -2 w h ic h h a s d i f f e r e n t e s t i m a t e p e r io d s , f o r w h l t e f i s h tw o I m p o r ta n t f e a t u r e s a r e e v i d e n t . 1 9 6 0 -1 9 8 2 d a t a r e s u l t s i n n eed e d t o c a t c h w h l t e f i s h . of e ffo rt is re la tiv e ly F i r s t , u s in g a n e s t i m a t e w h ich show s t h a t l e s s e f f o r t i s I n o t h e r w o rd s, CPE i s h ig h . lo w C atch p e r u n i t in th e second e s tim a te . E xcept f o r o b s e r v a ti o n s i n 1980, 1981 and 1982; a l l p o i n t s o f o b s e r v a t i o n fro m 1960 t o 1979 f a l l u n d e r o r v e r y n e a r th e y i e l d c u rv e ( F ig u r e V -2 ). I n F ig u r e V -1, ho w ev er, m ost o b s e r v a t i o n s a r e o u t s i d e t h e e s t i m a t e d e q u i l i b r i u m y ie ld cu rv e. F o r y e llo w 1 960s. p e r c h , h ig h l e v e l s o f e f f o r t and y i e l d o o o u rre d d u r in g Most p o s t-1 9 7 0 o b s e r v a t i o n s w e r e v e r y n e a r t h e o r i g i n , w h io h in d ic a te s t h a t th e am ount o f y e llo w p e rc h e a u g h t d e c l i n e d t o i t s lo w e s t l e v e l ( F ig u r e V -3 ). C a t f i s h h a v e tw o d i s t i n c t o b s e r v a t i o n p a t t e r n s , d u r in g th e 1960’ s and th e o t h e r i n th e 1 9 7 0 's . one o c c u r r in g D u rin g t h e 1 9 6 0 's , t h e r e w as a h ig h l e v e l o f e f f o r t w ith lo w e r y i e l d and d u r in g t h e 1 9 7 0 's t h e r e Total Catch (lb x 10^) Y = 474 E - 0 .0 0 6 6 E 8 •82 7 6 5 109 4 3 71 *74 2 1 100 125 E f f o r t x 10 Figure V-l. Estimated Equilibrium Catch (yield) and Effort Relation of Whitefish Using Linearized Surplus Production Technique (1960-1982) T o t a l C a tc h ( l b x 10 ) Y = 9 8 .1 5 E - 0 .0 0 0 7 4 E .82 .8 0 3. .66 60- 50 100 125 E f f o r t x 10 Figure V-2. Estimated Equilibrium Catch (Yield) and Effort Relation of Whitefish Using Linearized Surplus Production Technique (1971-1982) Total Catch (lb x 105) 115 E - 0 . 0 0 2 6 E 111 60 • 73 76 74 ’ 74 75 78 80 81 82 100 150 Figure V-3. Estimated Equilibrium Catch (Yield) and Effort Relation of Perch Using Linearized Surplus Production Technique (1960-1982) Effort x 10 T o t a l C a t c h (Lb x 10 ) 100 134 E - 0 . 0 0 4 5 E I 0 10 20 30 40 50 E f f o r t x 10 F i g u r e V - 4 . E s t i m a t e d E q u i l i b r i u m C a t c h ( y i e l d ) and E f f o r t R e l a t i o n of" C a t f i s h U sin g L in e a r iz e d S u r p lu s P r o d u c tio n T ech n iq u e (1 9 6 0 -1 9 8 2 ) Total Catch (in Lb x 10 ) 1 4 .0 Y = 34800 E - 5 1 .5 E 67 2 12.0 10.0 68 8.U 69 Hi 66 6.0 70 77 nr 0 5 10 15 l 20 I I 25 30 Figure V-5. Estimated Equilibrium Catch (Yield) and Effort Relation of Alewife using Linearized Surplus Production Technique (1971-1982) 1 35 Effort x 102 114 was a lower level of effort with a higher yield. It seems likely that current catfish production was below the point of maximum sustained yield (Figure V-4). A -lew ife p r o d u c t i o n , o n t h e o t h e r h a n d , sh o w ed a g r e a t d e a l o f f l u c t u a t i o n d u r in g th e 1960-1982 o b s e r v a ti o n p e r io d . Many o b s e r v a t i o n s f a l l o u t o f th e p r o d u c tio n c u rv e a s w e l l a s u n d e r th e c u r v e . E s tim a te o f B ioeconom lo A n a ly s is P s in g L i n e a r i z a t i o n . S u r p lu s PrpftwUgn TechplflMS S u b s t i t u t i n g t h e p a r a m e te r s k , q , and K w h ich have b e e n e s tim a te d (T a b le V -6) f o r w h l t e f i s h , u s in g 1960-1982 and 1971-1982 d a t a , i n t o t h e b io e c o n o m lo m o d e l g i v e s t h e r e s u l t p r e s e n t e d i n T a b le s V-7 and V -8. From th e s e e s t i m a t e s i t can b e s e e n t h a t optimum e f f o r t ( e f f o r t a t MET) is s m a l l e r t h a n e f f o r t a t MS7. ( y i e l d ) a t MET i s lo w e r th a n MSY. S i m i l a r l y , t h e amount o f f i s h c a u g h t In s p i t e o f lo w e r c a tc h r a t e s , MEY o b v io u s ly p r o v id e s h i g h e r p r o d u c e r s ' s u r p l u s (econom ic r e n t ) th a n MBY. Com paring t h e d i f f e r e n t e s t i m a t e s o f b io eco n o m lo v a l u e s fro m T a b le V -7 a n d T a b le V-8 shows t h a t t h e r e a r e c o n s id e r a b le d i f f e r e n c e s b etw ee n th e s e two e s t i m a t e s . T h ese d i f f e r e n c e s m ig h t be due t o d i f f e r e n t c a t c h p e r u n i t o f e f f o r t t r e n d s f o r t h e tw o s e t s o f o b s e r v a t i o n p e r i o d s exam in ed . The u s e o f 1960-1982 d a t a r e s u l t s i n a s m a l l e r e s t i m a t e o f t h e am o u n t o f e f f o r t w i t h much a h ig h e r y i e l d , w hich p r o v id e s a l a r g e p r o d u c e r 's s u r p l u s . On th e o t h e r h a n d , u s i n g 1 9 7 1 -1 9 8 2 d a t a g i v e s a l a r g e r e s t i m a t e o f t h e am o u n t o f e f f o r t w i t h a s m a l l e r y i e l d , w hich e v e n t u a l l y g i v e s a s m a l le r p r o d u c e r 's s u r p l u s . 115 T a b le V -7. E s tim a tio n o f B ioeconom lo V a lu e s f o r W h lte f is h (U sin g 1960-1982 d a t a ) P a ra m e te rs M agnitude U n its Optimum E f f o r t (Ee ) Maximum Econom ic Y ie ld (MEY) T o ta l V alu e P ro d u c t a t MEY T o t a l Long Run C o st a t MEY P r o d u c e r s ' S u r p lu s a t MEY 3 3 ,1 0 0 8 ,4 2 0 ,0 0 0 1 0 ,7 7 7 ,6 0 0 1 ,5 6 5 ,6 0 0 9 ,2 1 2 ,0 0 0 1000 f e e t o f 4 1 /2 in c h e s g i l l n e t pounds d o lla rs d o lla rs d o lla rs MSY E f f o r t (E*) Maximum S u s ta in a b le Y ie ld (MSY) T o ta l V alue P ro d u c t a t MSY T o ta l Long Run C o st a t MSY P r o d u c e r 's S u r p lu s a t MSY 3 5 ,9 0 0 8 ,5 0 0 ,0 0 0 1 0 ,8 8 0 ,0 0 0 1 ,6 9 8 ,0 0 0 9 ,1 8 2 ,0 0 0 1000 f e e t o f 4 1 /2 in o h e s g i l l n e t pounds d o lla rs d o lla rs d o lla rs T a b le V -8. E s tim a tio n o f th e B ioeconom lo V a lu e s f o r W h lte f is h (U sin g 1971-1982 d a t a ) P a ra m e te rs M agnitude Optimum E f f o r t (Ee ) Maximum Econom ic Y ie ld (MEY) T o ta l V alue P ro d u c t a t FEY T o t a l Long Run C o st a t MEY P r o d u c e r s ' S u r p lu s a t MEY MSY E f f o r t (E») Maximum S u s ta in a b le Y ie ld (MSY) T o ta l V alue P ro d u c t a t MSY T o t a l Long Run C o st a t MSY P r o d u c e r 's S u r p lu s a t MSY 4 1 ,0 0 0 2 ,7 7 0 ,0 0 0 3 ,5 4 5 ,6 0 0 1 ,9 3 9 ,3 0 0 1 ,6 0 6 ,3 00 6 6 ,0 0 0 3 ,2 3 4 ,0 0 0 4 ,1 4 0 ,0 0 0 3 ,1 2 2 ,0 0 0 1 ,0 1 8 ,0 0 0 U n its 1000 f e e t o f 4 1 /2 in o h e s g i l l n e t pounds d o lla rs d o lla rs d o lla rs 1000 f e e t o f 4 1 /2 in o h e s g i l l n e t pounds d o lla rs d o lla rs d o lla rs 116 A c o m p a r is o n o f t h e e s ti m a t e o f b io eco n o m lo v a l u e s from T a b le s V-7 and V-8 w ith th e e s ti m a t e d b io eco n o m lo v a lu e i n T a b le V -9 , r e v e a l s t h a t t h e r e p o r t e d e x i s t i n g e f f o r t i s much h ig h e r th a n th e e s ti m a t e d e f f o r t u s in g t h e b io e c o n o m lo m o d e l e i t h e r a t MEY o r a t MSY. e f f o r t e s tim a te d in T he am o u n t o f 1 9 7 3 w as a l m o s t t w i c e t h a t o f t h e optimum e f f o r t from t h e 1971-1982 d a t a ( T a b le V - 8 ) t a n d m o re t h a n t w i o e t h e o p tim u m e f f o r t fro m th e 1960-1982 d a t a (T a b le V -7 ). h i g h e r t h a n MEY o r MSY fro m t h e The t o t a l y i e l d i n 1973 was 1 9 7 1 -1 9 8 2 p e r i o d (T a b le V - 8 ) f b u t s m a l le r th a n MEY o r MSY from t h e 1960-1982 p e r io d (T a b le V -7 ). th e 1973 p r o d u c e r 's s u r p l u s w as l e s s th a n th e e s t i m a t e d H owever, p ro d u c e r s u r p l u s e s fro m b o th t h e 1960-1982 and 1971-1983 p e r i o d s (T a b le V-7 and V -8 ). T a b le V -9. E s tim a tio n o f t h e B ioeconom ic V a lu e s f o r W h lte f is h B ased o n 1973 D ata* P a ra m e te rs M agnitude T o ta l E f f o r t (TE) T o t a l Y ie ld (Y) T o ta l V alue P ro d u c t (TVP) T o t a l Long Run C o st (TLC) P r o d u c e r s ' S u r p lu s 7 8 ,9 0 0 3 ,4 5 1 ,0 0 0 4 ,4 1 7 ,2 8 0 3 ,7 3 1 ,9 7 0 6 8 5 ,3 1 0 U n its 1000 f e e t o f 4 1 /2 in c h e s g i l l n e t pounds d o lla rs d o lla rs d o lla rs * The d a t a ab o u t c o s t s and r e t u r n s w ere o b ta in e d from t h e M ich ig an S ea G ran t s tu d y i n 1976 c o n d u c te d by F . P a t t i a s o n and D.R. T alh elm (1 9 7 7 ). From t h i s c o m p a r is o n i t c a n n o t be f i r m l y c o n c lu d e d w h e th e r o r n o t w h l t e f i s h s t o c k s i n M ic h ig a n 's G re a t L a k e s w a t e r s a r e o v e r e x p l o i t e d . By c o m p a r in g t h e r e s u l t s f o u n d i n T a b l e V-7 w ith th o s e i n T a b le V -9, m ig h t be s a i d t h a t w h l t e f i s h s t o c k s h av e b een o v e r e x p l o i t e d b e c a u se th e e s t i m a t e fro m t h e 1960-1982 p e r io d shows t h a t l e s s e f f o r t c a n p ro d u ce a h ig h e r y i e l d th a n th e 1973 e f f o r t . B u t t h i s i s n o t t r u e u s in g d a t a from 117 T a b le V-8 w ith T a b le V -9. o p tim a l e f f o r t , Even th o u g h 1 9 7 3 's e f f o r t i s h i g h e r t h a n t h e t h e am o u n t o f f i s h p r e d i c t e d y i e l d e i t h e r a t MEY o r MSY. caught is a l s o h ig h e r th a n th e H o w e v e r, t h e s u r p l u s g a i n e d by t h e f is h e r m e n i n 1973 w ere s m a l le r th a n th e s u r p l u s g a in e d e i t h e r a t MSY o r MEY i n s p i t e o f h i g h e r c a t c h e s a n d e f f o r t s . y ie ld Maximum s u s t a i n a b l e (MSY) o f w h l t e f i s h w as e s ti m a t e d a t 8 .5 m i l l i o n pounds w ith th e maximum e f f o r t o f 3 5 ,9 0 0 u n i t s . m illio n . T he p r o d u c e r s u r p l u s w a s a b o u t $ 9 .2 Maximum econom ic y i e l d (MEY) was r e a c h e d a t 8 .4 m i l l i o n pounds w ith t h e maximum e f f o r t o f 3 3 ,1 0 0 u n i t s , a n d p r o d u c e r s u r p l u s o f $ 9 .2 m illio n . A ll o f th e s e e s t i m a t e d v a l u e s w ere o b ta in e d u s in g t h e 1960-1982 d a t a a s shown i n T a b le V -7. However, u s in g th e 1971-1982 d a t a ( T a b l e V -8 ) r e s u l t e d i n MSY o f 3 .2 3 m i l l i o n pounds w ith maximum e f f o r t o f 6 6 ,0 0 0 u n i t s and p ro d u c e r s u r p l u s o f $ 1 .0 8 m i l l i o n . Maximum econom ic y i e l d w as r e a c h e d a t 2 .7 7 m i l l i o n pounds w ith maximum e f f o r t o f 4 1 ,0 0 0 u n i t s , and $1 .6 1 m i l l i o n o f p ro d u c e r s u r p l u s . C o s t d a t a w e re n o t a v a i l a b l e f o r th e o t h e r f i s h s p e c i e s , t h e r e f o r e o n ly MSY a n d i t s e f f o r t w e re e s t i m a t e d f o r t h e s e s p e o i e s . Maximum s u s t a i n a b l e y i e l d o f p e r c h w as r e a c h e d a t 1 .2 2 m i l l i o n pounds a s th e maximum e f f o r t o f 2 1 ,5 0 0 u n i t s . w as $ 1 .0 m illio n F o r o a t f i s h , maximum s u s t a i n a b l e y i e l d p o u n d s w i t h t h e maximum e f f o r t o f 1 4 ,7 0 0 u n i t s . Maximum s u s t a i n a b l e y i e l d o f a l e w i f e was o b ta in e d a t 5 .8 7 m i l l i o n pounds w ith th e maximum e f f o r t o f 1 4 ,7 0 0 u n i t s . The f i n d i n g s f o r w h i t e f i s h i n d i c a t e d t h a t t h e w h i t e f i s h w as o v e r e x p l o i t e d , s in c e m ost o f t h e p r o d u c tio n o c c u r r e d i n t h e a r e a w e l l beyond MSY a s shown i n b o th F ig u r e s V-1 and V -2 . E s tim a tio n u s in g 1 9 6 0 -1 9 8 2 d a t a show t h a t t h e f is h e r m e n p ro d u ced o u t s i d e s u s t a i n a b l e y i e l d c u r v e , w here u s in g 1971-1982 d a t a th e p r o d u c tio n m o s tly f a l l s u n d er th e y ie ld 118 c u r v e , b u t b o th a r e o p e r a te d byond MSY. H o w e v e r, I t i s b e lie v e d th a t o u r r e n t w h i t e f i s h p r o d u c tio n i s v e r y n e a r th e ra n g e o f maximum s u s t a i n e d y ie ld . C lo s e o b s e rv a tio n s h o u ld be u n d e rta k e n to m o n ito r th e p e rfo rm a n c e o f w h i t e f i s h p r o d u c tio n r e g u l a r l y , in o l u d in g m easu rem en ts o f th e s i z e and w e ig h t o f w h i t e f i s h c a u g h t, sudden o o lla p s e o f th e s to o k s . I t is to h e lp re d u c e th e r i s k o f a d m itte d t h a t th e s to c h a s tic n a t u r e o f f i s h e r y b io m ass c a u s e s d i f f i c u l t i e s i n f o r e c a s t i n g t h e am o u n t o f fis h t h a t w i l l b e c a u g h t. The abundance o f f i s h s to o k s c a n v a r y i n many u n p r e d i c t a b l e w ays ( E v e r h a r t and Y oungs, 1 9 8 1 ). V a r ia tio n oan be c a u s e d by m i g r a t i o n , v a r i a b i l i t y i n th e spawn s u r v i v a l , o h an g es i n th e e n v iro n m e n t, p r o d u c t i v i t y , w e a th e r , s a l i n i t y , and c h a r a c t e r i s t i c s o f th e lo c a lity fis h e d . In a d d itio n , c a tc h a b ility i n t e n s i f i e s th e s to c h a s tic or c a tc h p e r u n it o f e f f o r t a ls o d ile m m a o f t h e f i s h e r y re so u rc e . m e a s u r e m e n t o f c a t c h p e r u n i t e f f o r t (CFE) i s im p r e o is e . p r o b le m s i n t h e a n a l y s i s of CPE d a t a . The T h is c a u se d M e a s u re m e n ts o f CPE a r e o v e r s i m p l i f i e d and u s u a l l y u n d e r e s ti m a t e d ( H ile , 1 9 6 2 ). 1 H ile g av e an exam p le r e g a r d i n g t h e t o t a l l i f t f is h e r m e n on y e llo w p e rc h . o f g i l l n e t s w h ic h w e r e s e t b y t h e T h e n e t s w ere s e t i n d eep w a te r f o r chubs and la k e h e r r i n g , b u t a l s o in c lu d e d y e llo w p e r c h . S in c e n e t s u s e d f o r chubs and h e r r i n g r a r e l y c a tc h any p e r c h , th e i n c l u s i o n o f th o s e n e t s i n t h e c o m p u ta tio n o f CPE f o r p e r c h y i e l d e d a v e ry lo w CPE f o r p e r c h . th is c o m p u ta tio n , one t h o u s a n d f e e t o f s m a l l m esh g i l l n e t s , i n s t a n c e , w as e s ti m a t e d t o c a t c h l e s s re a lity if In fo r t h a n 5 p o u n d s o f p e r c h w hen i n d i r e c t e d o n l y to w a r d p e r c h , t h e c a t c h e s w ere h ig h e r them 1P e r s o n a l c o m m u n ic a tio n w i t h F i s h e r y D iv is io n , MDNR a l s o r e v e a l s th e same p ro b lem i n th e m easurem ent o f CPE. 119 tw e n ty p o u n d s. a tte m p ts to T h is p ro b lem i s i n t e n s i f i e d f u r t h e r by t h e f i s h e r m e n 's t a k e s e v e r a l s p e c ie s s im u lta n e o u s ly when s e t t i n g t h e n e t s . T h e re fo re , any e f f o r t s d iffic u lt. t o o b t a i n a n u n b i a s e d m e a s u r e m e n t o f CPE i s W ith o u t c o r r e c t i n g t h i s problem * any a n a l y s i s u s in g CPE d a t a w ill g iv e in a c c u r a te r e s u l t s . F o r s i m p l e b io e o o n o m ic m o d e ls , t h i s s i t u a t i o n b eca m e m o re c r i t i c a l a s o n ly c a tc h and e f f o r t d a t a w e re u se d i n th e a n a l y s e s . CHAPTER VI ESTIMATION OF DEMAND AND SUPPLY PARAMETERS In tro d u c tio n The m ain p u rp o se o f t h i s c h a p t e r I s t o p r e s e n t an econom ic a n a l y s i s o f t h e dem and a n d s u p p l y o f s e v e r a l c o m m e r c ia l f i s h s p e c ie s . The e s t i m a t e s o f demand and s u p p ly p a ra m e te rs h av e b een o b ta in e d by s e v e r a l te c h n iq u e s and m e th o d s. By u n d e r t a k i n g dem and a n d s u p p ly a n a l y s i s i n t h i s s tu d y , s e v e r a l g o a l s a r e e x p e c te d t o b e a c c o m p lis h e d : - t o d e te r m in e econom ic f o r c e s and f a c t o r s t h a t i n f l u e n c e p r i c e s and q u a n t i t i e s o f f i s h p u rc h a se d ( s o ld ) , a s w e ll a s w hat c a u s e s p r i c e s and q u a n t i t i e s t o b e a t e x i s t i n g l e v e l s , to q u a n tif y and i s o l a t e v a r i a b l e s a f f e c t i n g t h e p r i c e and q u a n t i t y o f f i s h c o m m o d itie s. t o d e te r m in e th e r e s p o n s iv e n e s s o f p r i c e s o r q u a n t iti e s to c h a n g e s i n th e v a r i a b l e s o r f a c t o r s . I n a n a l y z i n g dem and a n d s u p p l y , a m o d el i s s p e c i f i e d b a se d upon s e l e c t e d econom ic p r i n c i p l e s . fis h d em an d ed i s One p r i n c i p l e s t a t e s t h a t th e q u a n t i t y o f d e t e r m i n e d by i t s p r o d u c ts , consum er in co m e, t a s t e , a d d itio n , a n o th e r p r in c i p le own p r i c e , p ric e o f s u b s titu te p o p u la tio n , and o th e r f a c t o r s . In s t a t e s t h a t th e q u a n t i t y o f f i s h s u p p lie d (p ro d u c e d ) i s d e te rm in e d by i t s own p r i c e , th e p r i c e o f o t h e r p r o d u c t s w hich a r e s u b s t i t u t e i n p r o d u c tio n , c o s t o f p r o d u c tio n , and te c h n o lo g y . 120 121 Based on economic principles, the expected effects caused by all these factors will be as follows: Demand f u n c t i o n . 1. W hen t h e p ric e s of fis h in c re a s e , th e q u a n tity o f f is h d em an d ed /p u rch a se d i s e x p e c te d to d e c r e a s e , on th e o t h e r h a n d , w hen t h e q u a n t i t y f i s h s o l d i n c r e a s e s , p r i c e i s e x p e c te d t o d e c r e a s e ( a l l p r i o e s u s e d h e r e a r e d o c k s id e p r i c e s ) . 2. I n c r e a s e s i n incom e a r e e x p e c te d t o r a i s e th e q u a n t i t y o f f i s h p u rc h a se d . T h is m ig h t n o t be t r u e i n th e c a s e o f i n f e r i o r o r G iffe n g o o d s, i n w h ic h t h e g o o d s d em an d ed w i l l d e c r e a s e i n s p i t e o f i n c r e a s e s i n in co m e. 3. P ric e s o f s u b s titu te p r o d u c t s i n c o n su m p tio n a r e e x p e c te d t o move i n th e sam e d i r e c t i o n w i t h r e s p e c t t o t h e q u a n t i t y o f fis h u n d e r c o n s id e ra tio n . When th e p r i c e o f s u b s t i t u t e goods d e c r e a s e , i t i s l i k e l y t h a t th e q u a n t i t y o f s u b s t i t u t e dem anded w i l l in c re a s e , re s p e c tiv e goods ( f is h ) th e re fo re , goods th e q u a n tity o f th e d e m a n d e d /s o ld w i l l d e c r e a s e . T he c l o s e r th e s u b s t i t u t e , th e m ore th e e f f e c t w i l l be f e l t . S u p p ly F u n c tio n 1. As th e price of fish increases, h a r v e s t e d / p r o d u c e d by t h e f i s h e r m e n . more fish w ill be F is h e rm e n w ill be m o tiv a te d t o i n c r e a s e t h e i r p r o d u c tio n . 2. Prices of opposite s u b s titu te goods in p r o d u c t i o n w i l l move i n a n d irection quantity c o n s id e ra tio n . to the of fish under I f t h e p r i c e o f s u b s t i t u t e g o ods i n c r e a s e s , 122 th e p r o d u c tio n of fis h m ig h t d e c r e a s e , a s m ost f is h e r m e n ( p r o d u c e r s ) w i l l now p ro d u c e more s u b s t i t u t e g o o d s r a t h e r t h a n th e r e s p e c t i v e f i s h p r o d u c tio n . 3. F a c t o r o o s t s o r c o s t s o f p r o d u c tio n and t h e q u a n t i t y o f f i s h p r o d u c e d t e n d t o move i n o p p o s i t e d i r e c t i o n s . Commonly, w h e n e v e r c o s t s i n c r e a s e , th e f is h e r m e n m ig h t p a s s them a lo n g i n t h e fo rm o f h ig h e r f i s h p r i c e s . T h is w i l l d r i v e u p p r i c e , a n d c o n s e q u e n t l y w i l l d r i v e down t h e q u a n t i t y dem anded. In o r d e r t o d e a r t h e m a rk e t, l e s s o f th e f i s h co m m o d ity m u s t be o f f e r e d o t h e r w i s e t h e f i s h e r m e n 's p r o f i t a t c u r r e n t p r i c e s w i l l go down. As a r e s u l t , some f is h e r m e n m ig h t b e d r iv e n o u t o f b u s i n e s s and a l l p r o d u c e r s w i l l end up w ith a s m a lle r am ount o f f i s h p ro d u c e d . Some v a r i a b l e s ( f a c t o r s ) , a lth o u g h c o n s id e r e d d o m in an t i n a f f e c t i n g dem and s u c h a s c o n s u m e r t a s t e s , a re not a v a ila b le . In t h i s case, in c o m e , o t h e r th a n i t s e f f e c t on dem and, i s c o n s id e r e d a good p ro x y f o r th e t a s t e v a r i a b l e . In a d d itio n , t h e c o s t o f f a c t o r s w h ic h h a v e a n e f f e o t on th e s u p p ly f u n c t i o n a r e n o t a v a i l a b l e , and t h e r e f o r e e f f o r t o r c a t c h p e r u n i t o f e f f o r t i s u s e d a s i t s p ro x y . The m o d e l u s e d i n th is s t u d y w i l l b e b a s e d o n t h e c e t e r i s p a r ib u s ( o t h e r th i n g s b e in g e q u a l) a s s u m p tio n , t h a t i s , o t h e r v a r i a b l e s w h ich c a n n o t b e m e a s u r e d a r e h e l d c o n s ta n t. B ased o n in f o r m a tio n p ro v id e d by t h e F i s h e r i e s D iv is io n o f t h e MDNR a b o u t p o s s i b l e s u b s t i t u t e s i n th e c o n s u m p tio n (d e m a n d ) a n d p r o d u c t i o n (supply) o f each fis h s p e c i e s e x a m in e d t h e m odel was s p e c i f i e d . The p r i c e s o f s u b s t i t u t a b l e co m m o d ities w ere in c o r p o r a te d i n t o t h e m o d e l t o 123 e s t i m a t e demand an d s u p p l y f u n c t i o n s . T he s u b s t i t u t e goods f o r th e demand f u n c t i o n s o f e a c h s p e c i e s a r e : b e e f, W h ite f is h = s e a f o o d , s h rim p , c o d , f i l l e t , p o u l t r y , and f lo u n d e r a r e c o n s id e r e d s u b s t i t u t e s f o r w h i t e f i s h . sm o k ed Chubs = fis h , ocean h e r r in g ,, and canned fis h are c o n s id e r e d s u b s t i t u t e s f o r c h u b s. P e rc h = ocean p e rc h , s h r im p a n d s c a l l o p s a r e s u b s t i t u t e s f o r p e rc h . C a tfis h = w h ite fis h , tro u t, fille t and o t h e r o c e a n fo o d a r e c o n s id e r e d s u b s t i t u t e s f o r c a t f i s h . A le w ife = fo r a le w ife , t h e r e w as no s u b s t i t u t e u s e d i n th e m odel, b e e f w as u s e d a s a c o m p le m e n ta r y g o o d r a t h e r th a n a s u b s titu te . The s u b s t i t u t e g o o d s f o r s u p p ly a r e : W h ite f is h = t r o u t w as c o n s id e r e d a s th e c l o s e s t s u b s t i t u t e . Chubs= t h e s u b s t i t u t e g o o d s f o r ch u b s w ere w h i t e f l h , t r o u t , and p e rc h . •* P e rc h = Chubs and c a t f i s h w e re t h e s u b s t i t u t e s f o r p e r c h , C a tfis h = p e rc h w as t h e o n ly good s u b s t i t u t e f o r c a t f i s h , A le w ife = no s u b s t i t u t e . S in c e th e d e m a n d s e s t i m a t e d i n t h e m o d e l w e re d em an d s a t t h e d o c k s id e l e v e l ( n o t a t consum er l e v e l ) , t h e r e w ere no d i r e c t s u b s t i t u t e s b e tw e e n f i s h s p e c ie s . The d i r e c t s u b s t i t u t e o f g o o d s i s e x p e c te d t o 124 o c c u r a t t h e consum er l e v e l ( r e t a i l m a r k e t) . H ow ever, th o s e s u b s t i t u t e g o o d s w e re s t i l l f u n c ti o n in g a s i n d i r e o t s u b s t i t u t e s ( d e r iv e d ) i n te rm s o f in f l u e n c i n g th e p r o c e s s o r s ' o r w h o l e s a l e r s ' d e c i s i o n s o n how much and a t w h a t p r i c e t h e y w o u ld b u y t h e f i s h from M ic h ig a n 's G r e a t L akes ( a t d o o k s id e l e v e l ) . A l l t h e p r i n c i p l e s d i s c u s s e d a b o v e , a lo n g w ith s t a t i s t i c a l t e s t s , w i l l b e u s e d t o d e te r m in e th e b e s t r e s u l t s from th e e s t i m a t e s o f dem and and s u p p ly . E s tim a tio n P ro c e d u re To e s t i m a t e demand and s u p p ly f u n c t i o n s , two s t e p s w ere u s e d t o ru n th e r e g r e s s i o n . 1. A s e rie s o f e q u a t i o n s w e re ru n t r e a t i n g t h e q u a n t i t y o f f i s h la n d e d ( c a t c h ) a s a d e p e n d e n t v a r i a b l e w h ic h w as a f f e c t e d by a l l o t h e r in d e p e n d e n t v a r i a b l e s . 2. T h e n , a s e r i e s o f e q u a t io n s w ere ru n t r e a t i n g p r i c e a s a d ep en d en t v a ria b le w h ic h w as a ffe o te d by o th e r in d e p e n d e n t v a r i a b l e s . I n s e l e c t i n g w h ic h v a r i a b l e s t o i n c l u d e a s e r i e s o f e q u a t io n s , m u l t i c o l l i n e a r i t y am ong t h e i n d e p e n d e n t v a r i a b l e s c o n s id e ra tio n . w as ta k e n in to T h is w as done by u s in g a c o r r e l a t i o n c o e f f i c i e n t m a t r i x , t h a t i s , by a v o id in g t h e v a r i a b l e s w hich hav e h ig h m u l t i c o l l i n e a r i t y i n t h e sam e e q u a t i o n . As m e n tio n e d by Kmenta (1971)» m u l t i c o l l i n e a r i t y i s a q u e s ti o n o f d e g re e an d n o t o f k in d . T he d i s t i n c t i o n is n o t b e tw e e n t h e p r e s e n c e o r a b s e n c e o f m u l t i c o l l i n e a r i t y , b u t b etw ee n i t s v a r i o u s d e g r e e s , o r th e d e g re e t o w hich two o r m o re i n d e p e n d e n t v a r i a b l e s a r e 125 c o r r e l a t e d t o e a c h o t h e r o r a l i n e a r c o m b in a ti o n o f o t h e r i n d e p e n d e n t v a ria b le s . A h i g h d e g r e e m u l t i c o l l i n e a r i t y i s h a rm fu l i n th e s e n s e t h a t th e e s tim a te s o f th e r e g r e s s io n c o e ffic ie n ts a re not p re c is e . The i m p r e c i s i o n a r i s e s b e c a u s e o f t h e l a r g e v a r i a n c e s o f t h e l e a s t s q u a re e s tim a to rs . T hese h ig h v a r ia n c e s o c c u r b e c a u s e m u l t i c o l l i n e a r i t y w i l l p r e v e n t t h e GLS p r o c e d u r e from b e in g g iv e n enough in d e p e n d e n t v a r i a t i o n to c a l c u l a t e th e e f f e c t i t h a s on th e d ep en d e n t v a r ia b le 1 9 8 3 ). d e v e lo p in g .T h e r e f o r e , in re g re s s io n (K e n n e d y , m o d e ls , th e m u l t i c o l l i n e a r i t y p ro b lem w i l l be re d u c e d by in o l u d in g v a r i a b l e s i n t h e m o d el w h io h have c o r r e l a t i o n c o e f f i c i e n t s r £ 0 .8 0 . C o n s e q u e n tly , some v a r i a b l e s w i l l be e x c lu d e d , o r in c lu d e d i n s e p a r a t e e q u a t io n s . s tu d y , th e c o r r e l a t i o n c o e f f i c i e n t m a tr ix among th e v a r i a b l e s , in T a b le s V I-1 , In th is a s show n V I - 2 , V I-3 * an d V I - 4 , w i l l be u s e d a s a g u i d e i n e s t i m a t i n g demand and s u p p ly f o r e a c h f i s h c o m m o d ity . H o w e v e r, t h i s r u l e m ig h t be v i o l a t e d i f , i n th e a u t h o r 's ju d g m e n t, t h e r e a r e v a r i a b l e s to o im p o r ta n t t o be e x c lu d e d d e s p i t e h ig h m u l t i c o l l i n e a r i t y . case, In th is t h e r u l e o f th u m b a s s u g g e s t e d b y Kennedy (1 9 8 3 ) w i l l be u s e d . T hat i s , m u ltic o llin e a rity i s ig n o re d i f t h e ' R2 fro m th e r e g r e s s i o n e x c e e d s t h e R2 o f a n y i n d e p e n d e n t v a r i a b l e re g re s s e d on th e o th e r in d e p e n d e n t v a r i a b l e s o r i f th e " t " s t a t i s t i c s a r e a l l g r e a t e r th a n tw o. A n o th e r f a c t o r w h ic h w i l l b e c o n s i d e r e d i s th e e x is te n o e o f a s e r i a l c o r r e l a t i o n , a s i t u a t i o n i n w h ich t h e d i s t u r b a n c e o c c u r r i n g a t o n e p o i n t o f o b s e r v a t i o n i s c o r r e l a t e d w ith any o t h e r d i s t u r b a n c e . a n o t h e r w o r d s , i t m i g h t be s a i d t h a t t h e e f f e c t of In a d is tu rb a n c e o c c u r r i n g i n one p e r io d may c a r r y o v e r t o a n o th e r p e r io d . The p re s e n c e o f a s e r i a l c o r r e l a t i o n w i l l c a u s e th e l e a s t s q u a re e s t i m a t o r s t o become Table VI-1. C orrelation C oefficients Aaong the V ariables Used In the E stla atlo n o f Deaand and Supply Funotlons o f W hltefish T 1.000 QV .091 1.000 PUD -.916 -.923 QT .481 -.263 1.000 .858 -.361 -.919 -.842 -.4*6 -.358 .403 -.104 PTD PBD PCFD 1.000 .191 .818 1.000 .340 1.000 .640 -.680 .009 .763 -.419 1.000 .020 -.859 -.420 .031 -.561 -.084 .747 1.000 .611 .623 1.000 .889 .844 .678 1.000 .776 .840 .610 .884 1.000 .802 .870 .634 .926 .960 1.000 .890 .825 .592 .934 .870 .896 1.000 .455 .454 1.000 DICD .962 .802 -.848 PSD .687 .608 -.612 PFLD .851 .660 -.771 PCD .836 -.103 -.802 -.391 .705 -.793 -.158 -.784 -.209 PFID .879 .860 .825 -.785 -.191 -.793 -.314 .717 -.777 -.010 -.806 -.507 PSTD M WTE .707 .793 -.737 .346 -.534 -.362 .416 .633 .445 .379 .428 WCPE .883 .883 -.882 .245 -.881 -.323 .704 .837 .590 .802 .851 .833 .821 .468 1.000 .329 -.863 -.449 .306 -.640 -.511 .841 .803 .619 .817 .806 .789 .876 .682 .879 1.000 .708 .623 .509 .554 .708 .710 .603 .833 .555 .633 .284 .598 .677 -.512 -.172 .489 .304 .216 .158 .363 .516 .403 .632 QVH QWO .763 .927 -.897 .769 -.750 PGD .497 .628 -.463 FWD1 .913 -.280 -.327 T QV .270 .267 FVD QT .457 -.130 -.326 -.224 -.209 -.404 -.424 FTP FBD PCFO DICD PSD PFLD PCD .308 - .3 2 0 PFID PSTD .058 -.471 WTE VCPE 1.000 •633 1.000 -.363 *.123 -0.282 OWN QWO POD 1.000 PWD1 Table VI-2. Correlation C oefflolent Among the Variables Used in the Estimation o f Demand and Supply Functions of Chubs QCH 1.000 PCHD -.618 1.000 PCHD1 -.767 .742 1.000 PHD -.649 .531 .514 -.056 .496 1.000 -.506 .031 PBD 1.000 PCFD -.830 .784 .852 -.906 .586 .659 .689 -.419 .636 -.430 1.000 DICD .7*7 1.000 PFLD -.828 .765 .746 .703 -.391 .889 .84* 1.000 PSTD -.838 .758 .818 .546 -.507 .890 .825 •93* 1.000 PFID -.844 .799 .718 .802 .918 .926 896 PGD -.437 .259 .412 .618 -.311 .552 -.172 .555 .284 .304 .158 1.000 363 ,698 -.777 -.223 1.000 .146 -.26* -.52* 1.000 013 CHTE CHCPE QCHH .898 -.384 -.596 -.476 -.144 -.338 -.168 -.099 -.249 -.135 QCHG .663 -.718 -.443 -.556 .644 -.623 -.328 -.519 PHD .788 -.471 -.571 .741 .655 PPD PTD .565 -.613 -.928 -.674 -.802 PCHD PCHD1 .215 -.7*0 -.587 -.761 719 -.693 -.3*2 .*31 .188 1.000 .213 -.668 -.620 -.715 - .3 1 0 .*85 .020 .976 .403 -.680 -.848 -.771 -.284 .760 -.810 .837 .653 -.566 .791 -.529 -.537 -.641 QCH .358 -.005 PHD 1.000 .3*0 -.763 -.859 -.802 PBD PCFD DICD PFLD 667 -.67* 1.000 .520 1.000 .751 -.220 .509 777 -.785 -.*63 .888 -.686 -.680 -.795 ,813 .031 -.715 •317 1.000 ,806 -.793 -.512 .755 -.326 .631 .672 .858 -.755 PSTD CHTE CHCPB QCHH QCHG PHD PFID POD PPD 1.000 PTD Table VI-3. C orrelation Coefflolente Among the Variablee Oaed in tbe Estimation o f Demand and Supply Functions o f Tellow Peroit 1.000 QP PPD -.726 PPD1 -.7*6 .768 1.000 POPD -.680 .790 1.000 .718 1.000 PSD -.512 .633 .63* .811 1.000 PSCD -.827 .739 .677 .661 .587 PCHD -.552 .7*1 .660 .617 .519 PC1TD DICD POD 1.000 .386 1 .000 .676 -.705 -.5*7 -.867 -.657 -.728 -.4*1 1.000 -.865 .810 .825 .726 .623 .869 .586 -.666 1.000 -.263 .317 .3** .616 .*89 .323 .259 -.7*1 .28* PTE .852 -.500 -.668 -.463 .391 -.71* -.35* .085 -.358 -.111 -.3*5 -.17* -.012 -.329 .352 -.*70 -.126 -.195 -.063 QPO .329 -.602 -.186 -.*63 -.216 -.1 9 0 QP PPD PPD1 POPD PSD •1 M U > O PCPE QPH PSCD -.289 -.58* 1.000 .450 -.785 -.169 .328 1.000 .031 -.201 -.398 1.000 .361 -.1*1 .327 -.465 -.0*0 .486 .500 -.28* -.27* -.03* PCHD PCATD DICD POD PTE PCPE 1.000 .635 1.000 QPH QPO Table VI-4. C orrelation C oefflclenta Among the Variables Used In the Estimation of Demand and Supply Functions o f Catfish QCAT 1.000 PCATD -.864 1.000 PCAD1 .586 .530 1.000 FVD .747 .7*15 .136 PTD -.760 .875 •357 .858 1.000 .598 -.596 -.061 -.785 -.793 PFID PSTD PPD PBD PGD CATE CACPE QCAH QCAG DICD 1.000 1.000 .708 -.678 -.163 -.777 -.806 -.896 1.000 .746 -.705 -.233 -.795 -.775 .888 .813 1.000 -.214 .228 -.222 .340 -.314 -.507 -.284 .403 .654 -.711 -.010 -.431 .338 -.242 -.463 -.512 .574 -.570 .601 .564 .579 .567 -.666 .317 -.172 .615 .622 -.725 -.307 •363 .543 -.567 -.420 .785 -.850 -.282 -.868 -.865 1.000 .158 .594 1.000 .407 -.085 .538 .564 .733 -.707 -.652 .705 .151 -.280 .584 .531 .715 -.670 -.619 .682 .141 -;232 .011 -.848 -.859 QCAT PCATD PCAD1 FVD PTD .918 .825 -.865 -.420 PFID PSTD PPD PBD 1-.000 .625 -.592 .284 -.769 POD 1.000 •533 -.584 .488 -.564 1.000 .991 1.000 .768 -.699 CATE CACPE QCAM QCAG DICD 130 V a r ia b l e s name: T QW PWD QT PTD PBD PCFD DICD PSD PFLD PCD PFID PSTD WTE WCFE QWM QWG PGD PWD1 QCH PCHD PCHD1 PHD CHTE CHCPE QCHM QCHG PPD QP PPD1 POPD PSCD PTE PCPE QDM QPG PCATD QCAT PCAD1 CATE = = a = s = s = = s tim e 1 y e a r q u a n tity o f w h ite fis h p ric e o f w h ite fis h d e fla te d q u a n t i t y o f la k e t r o u t p r i c e o f la k e t r o u t d e f l a t e d p ric e o f b e e f d e fla te d p r i c e o f can n ed f i s h d e f l a t e d d is p o s a b le incom e p e r c a p i t a d e f l a t e d p r i c e o f sh rim p d e f l a t e d p r i c e o f f lo u n d e r d e f l a t e d a p r i c e o f cod d e f l a t e d = p ric e o f f i l l e t s d e fla te d a p r ic e o f s te a k s d e fla te d a w h ite fis h t o t a l e f f o r t a w h i t e f i s h o a tc h p e r u n i t o f e f f o r t a q u a n t i t y o f w h l t e f i s h from M ich ig an G re a t L akes s u b t r a c t e d f r o i US G r e a t L akes a q u a n t i t y o f w h i t e f i s h M ich ig an G r e a t L ak es s u b t r a c t e d from th e w hole G re a t L ak es a p r ic e o f g a s o lin e d e f la te d a l a g one y e a r o f p r ic e o f w h ite fis h d e f la te d a q u a n t i t y o f ohubs a p r i c e o f ch u b s d e f l a t e d a l a g one y e a r o f p r io e o f ohubs d e f l a t e d a p ric e o f ocean h e rrin g d e f la te d a ch u b s t o t a l e f f o r t a ch u b s o a tc h p e r u n i t o f e f f o r t a q u a n t i t y o f ch u b s fro m M ich ig an G re a t L ak es s u b t r a c t e d from US G r e a t L ak es a q u a n t i t y o f ohubs fro m M ich ig an G r e a t L ak es s u b t r a c t e d from t h e w hole G re a t L akes a p r i c e o f p e ro h d e f l a t e d a q u a n t i t y o f p e rc h a l a g one y e a r o f p r i c e o f p e rc h d e f l a t e d a p r i c e o f o c e a n p e ro h d e f l a t e d a p ric e o f s c a llo p s d e fla te d a p e rc h t o t a l e f f o r t a p e ro h c a tc h p e r u n i t o f e f f o r t a q u a n t i t y o f p e rc h from M ich ig an G re a t L ak es s u b t r a c t e d from US G r e a t L akes a q u a n t i t y o f p e rc h from M ich ig an G r e a t L akes s u b t r a c t e d from t h e w hole G re a t L akes a p ric e o f c a tf is h d e fla te d a q u a n tity o f c a t f is h a l a g one y e a r o f p r i c e o f c a t f i s h d e f l a t e d a c a tfis h to ta l e ffo rt 131 CACPE = c a t f i s h c a t c h p e r u n i t o f e f f o r t QCAM = q u a n t i t y o f c a t f i s h from M ichigan G r e a t L akes s u b t r a c t e d from US G re a t L akes QCAG = q u a n t i t y o f c a t f i s h from M ich ig an G r e a t L akes s u b t r a c t e d from th e w hole G re a t L akes QAL = q u a n tity o f a le w ife PALD s p r i c e o f a le w i f e d e f l a t e d PALD1 = l a g one y e a r o f p r i c e o f a le w if e d e f l a t e d ALTE = a le w if e t o t a l e f f o r t ALCPE s a le w if e c a t c h p e r u n i t o f e f f o r t QALM s q u a n t i t y o f a l e w i f e from M ich ig an G re a t L ak es s u b t r a c t e d from US G r e a t L akes HTEG = w h i t e f i s h t o t a l e f f o r t w ith g i l l n e t WCEG = w h i t e f i s h c a tc h p e r u n i t o f e f f o r t w ith g i l l n e t 132 i n e f f i c i e n t e s tim a to rs . T h is i s d ue t o th e f a c t t h a t th e d ep en d en ce among t h e d i s t u r b a n c e s r e d u c e s t h e e f f e c t i y e n u m b er o f in d e p e n d e n t p ie c e s o f in f o r m a tio n i n th e sam ple (K m entai 1971)* T h e r e f o r e , t o oheck s e r i a l c o r r e l a t i o n i n th e m o d e l, a D u rb ln -U a ts o n t e s t i s em ployed. To a p p ly t h i s t e s t , t h e v a lu e t h e v a lu e o f s t a t i s t i c "d " i s c a l c u l a t e d b y : T d = £ t= 2 (® t ” e t - 1 ^ 2 6 * T £ ef 2 t= 1 1 w here e i s th e o r d in a r y l e a s t s q u a r e s r e s i d u a l . v a lu e i s com pared w ith th e t a b l e v a l u e . Then th e c a l c u l a t e d "d " The d e c i s i o n r u l e s a r e : if d >du ; th e h y p o th e s is o f no s e r i a l c o r r e l a t i o n i s a c c e p te d , if d t h e t e s t i s i n c o n c lu s iv e ( t h e h y p o th e s is i s n e i t h e r a c c e p te d n o r r e j e o t e d ) . d u s v a lu e o f d f o r u p p e r l i m i t dL = v a lu e o f d f o r lo w e r l i m i t E s tim a te s U sin g , t h e S in g le E q u a tio n Method In e s tim a tin g dem and a n d s u p p l y f u n c t i o n s f o r eac h s p e c i e s w ith d i f f e r e n t m o d els and t e c h n i q u e s , many c o m b i n a t i o n s o f v a r i a b l e s w e re trie d . F o r e a c h f i n a l e q u a tio n p r e s e n te d t h e number o f r u n s a tte m p te d f o r ea c h e q u a tio n v a r i e d from 10 t o 60 r u n s e a o h . The e q u a t io n y i e l d i n g th e m ost s a t i s f a c t o r y r e s u l t was th e n s e l e c t e d a s th e b e s t e s t i m a t e . 133 Demand Estimations W h ite fis h A n u m b er o f c o m b i n a t i o n s o f v a r i a b l e s w e re u s e d t o e s ti m a t e th e demand f u n c t i o n o f w h i t e f i s h . E q u a tio n ( 6 .1 ) i n T a b le V I-5 w as s e l e c t e d a s t h e b e s t e s t i m a t e fr o m am ong t h e o t h e r e q u a t io n s . The q u a n t i t y o f w h i t e f i s h , a s w e ll a s th e p r i c e , w e re p l a c e d a s d e p e n d e n t v a r i a b l e s . Most o f th e . s ig n s o f th e c o e f f i c i e n t p a r a m e te r s i n e q u a t io n ( 6 .1 ) a r e as e x p e c te d e x c e p t f o r t h e d e f l a t e d s u b s titu te fo r w h ite fis h p ric e o f f i l l e t c o n s u m p t io n . p a ra m e te r i s e x p e c te d t o be p o s i t i v e . d e fla te d (P F ID ), u s e d a s a T he s i g n o f t h e f i l l e t p r i c e The s ig n o f c o e f f i c i e n t s o f t h e p r i c e o f s h r im p (PSD) and d i s p o s a b le incom e p e r c a p i t a (DICD) are p o s itiv e , a s e x p e c te d . T he n e g a t i v e r e l a t i o n s h i p b e t w e e n t h e q u a n t i t y o f f i s h demanded and t h e d e f l a t e d p r i c e o f w h i t e f i s h i n d l o a t e s th a t any in c r e a s e dem anded. in p r i c e w i l l d e c r e a s e th e q u a n t i t y o f w h i t e f i s h The c o e f f i c i e n t f o r th e p r i c e o f w h i t e f i s h from t h e e s ti m a t o r i s s i g n i f i c a n t a t th e .01 l e v e l . The d i r e c t i o n o f q u a n t i t y changes is a l s o c o n s i s t e n t w ith th e ch an g e i n in co m e, w h ere i n c r e a s e s i n incom e a r e a s s o c i a t e d w ith p o s i t i v e c h a n g e s i n q u a n t i t y . te r m s o f p r i c e e la s tic ity . a p ric e e l a s t i c i t y a ls o show n i n E q u a tio n ( 6 .1 ) y i e l d s a f a i r l y h ig h p r i c e e l a s t i c i t y o f - 2 .3 8 a t t h e mean v a l u e . le a d to T h is i s Use o f 1973-1982 a v e r a g e v a l u e s e s ti m a t e o f - 1 .2 4 . The f a c t t h a t b o th o f th e s e e s t i m a t e s r e s u l t i n a b s o l u t e v a l u e s g r e a t e r t h a n o n e i n d i c a t e s t h a t t h e f i s h e r m e n w o u ld b e a b l e t o l a n d m ore w h i t e f i s h and w ould be w i l l i n g t o r e c e i v e l o w e r p r i c e s w h ic h w o u ld r e s u l t i n h i g h e r t o t a l re v e n u e s . P r ic e incom e e l a s t i c i t y i s a l s o h ig h , 1 .4 a t th e mean v a l u e s . H owever, i t d r o p s t o o n l y 0 . 6 i f 1 9 7 3 -1 9 8 2 a v e r a g e v a l u e s a r e u s e d . T able V I-5 . The E stim ated Demand F u n c tio n s f o r S e v e ra l F ish S p e c ie s on M ichigan G reat Lakes Commercial F is h e ry w ith O rd in ary L e a st S quares W h ite fis h QW = 7111963 - 4699468 ( 2 .4 ) ( 6 .2 ) R2 = 0.907 PWD + 894549 PSD - 1993891 PFID+452.6 DICD ( 1 .3 ) ( 1 .9 ) ( 1 .3 ) D-W S t a t i s t i c s = 1 .5 7 F S t a t i s t i c s = 4 4 .2 Chubs QCH = 8525001 - 2372964 PCHD + 3958459 PBD + 2 1 7 1 9 1 0 PCFD- 1512 DICD ( 3 .2 ) ( 2 .8 ) ( 2 .7 ) ( 2 .7 ) ( 7 .2 ) R2 = 0.91 D-W = 1.99 Perch QP = 3044476 - 1202093 ( 6 .2 ) ( 1 .4 ) R2 =0 .7 3 C a tf is h QCAT = 807043 - 867364 ( 2 .9 ) ( 5 .9 ) R2 = 0.81 ( 6 .3 ) F = 15.9 PCATD + 32818 PSTD + 58923 PBD ( 1 .0 ) ( 0 .4 ) D-W = 1.47 ( 6 .2 ) F = 42 .9 PPD + 151642 PSD - 526050 PSCD ( 0 .3 ) ( 3 .6 ) D-W = 1.76 (6 .1 ) (6 .4 ) F = 2 6 .0 A lew ife QAL = 2031991300 - 36043716 PALD - 9670131 PBD + 5461 DICD - 1045593 T ear (6 .5 ) ( 4 .1 ) ( 0 .8 ) ( 1 .9 ) ( 3 .6 ) (4 .1 ) R2 =0.5 7 D-W= 1 . 2 5 F = 4 .7 r ----------------------------------------------------------------------N ote: Numbers i n p a r e n th e s is a r e " t" v a lu e s . 135 C ro ss p r i c e e l a s t i c i t y o f demand w ith sh rim p w as 0 .4 i n d i c a t i n g t h a t a s th e p r ic e o f sh rim p i n c r e a s e s by one p e r c e n t , th e q u a n t i t y o f w h i t e f i s h demanded a t th e d o c k s id e i n c r e a s e s by 0 .4 p e r c e n t. Chubs T he dem and f u n c t i o n f o r ch u b s was e s ti m a t e d u s in g e q u a t io n ( 6 . 2 ) . The c o e f f i c i e n t f o r chub p r i c e i s s i g n i f i c a n t a t th e .0 1 l e v e l . The q u a n t i t y o f chubs h a s a n e g a tiv e r e l a t i o n s h i p w ith p r i c e and a p o s i t i v e r e l a t i o n s h i p w ith th e p r i o e o f s u b s t i t u t e g o o d s , nam ely b e e f a n d c a n n e d fis h , a s e x p e c te d . u n e x p e c te d . H ow ever, th e n e g a t iv e s ig n o f incom e p e r c a p i t a w as V a rio u s c o m b in a tio n s o f v a r i a b l e s w e re e x a m in e d , b u t n o n e y ie ld e d a p o s itiv e s i g n w i t h r e s p e c t t o in co m e. demand f o r c h u b s i s - 0 . 5 1 . in c re a s e d to - 1 .6 6 . r a t h e r h ig h a t 1 .4 8 . P r ic e e l a s t i c i t y o f U sing 1973-1982 a v e r a g e s , C ro ss p r ic e e la s tic ity p rio e e l a s t i c i t y o f dem and w ith b e e f was S im ila r ly , th e c ro s s p r ic e e l a s t i c i t y w ith oan n ed f i s h w as 1 .3 4 a t th e mean v a l u e . P e rc h The demand f u n c t i o n a s shown i n e q u a t io n ( 6 .3 ) i s t h e b e s t e s t i m a t e from t h e v a r i o u s e s t i m a t e s exam in ed on p e r c h , w here t h e c o e f f i c i e n t f o r th e p r ic e o f p erch i s s i g n i f i c a n t a t t h e .1 0 l e v e l . The s ig n o f th e c o e f f i c i e n t s , e x c e p t f o r s c a l l o p p r i c e (PSCD), w ere a s e x p e c te d . c o m b i n a t i o n s , w h ic h i n c l u d e O th e r t h e In c o m e p e r o a p i t a a s t h e in d e p e n d e n t v a r i a b l e w e r e e x a m in e d , b u t a l l r e s u l t e d in u n e x p e c te d n e g a tiv e r e l a t i o n s h i p s b e tw e e n incom e and t h e q u a n t i t y o f p e rc h dem anded. 73 p e r c e n t o f th e v a r i a t i o n in th e q u a n tity o f p e r c h dem anded Only is e x p l a i n e d b y t h e v a r i a b l e i n th e e q u a t io n , h o w ev er, t h e r e i s no s e r i a l 136 c o r r e l a t i o n o c e u r r i n g i n th e e s t i m a t e . o f dem and w as - 0 . 8 The e s ti m a t e o f p r i c e e l a s t i c i t y a t t h e m ean v a l u e . p r ic e e l a s t i c i t y in c re a s e d d r a s t i c a l l y U sin g 1973-1982 a v e r a g e s , th e to - 4 .1 2 5 . T h i s i n c r e a s e w as p r o b a b l y c a u s e d by t h e s u b s t a n t i a l d e c r e a s e i n p e rc h l a n d in g s due t o re s tric tio n s im p o s e d b y MDNR i n th e d e t e r i o r a t i o n o f th e y e llo w p e rc h s t o c k s . 1 9 7 0 's to p re v e n t fu r th e r I t seem s, t h e r e f o r e , t h a t th e s m a ll i n c r e a s e s i n th e p r i c e o f p e rc h g e n e r a t e s a h u g e d e c r e a s e i n t h e q u a n t i t y o f p e rc h dem anded. C a tfis h The e s t i m a t e of th e d em an d f u n c t i o n f o r c a t f i s h is show n i n e q u a tio n ( 6 . 4 ) . The l e v e l o f s i g n i f i c a n c e f o r t h e p r i c e o f c a t f i s h .0 1 . s ig n s A ll th e show n i n t h i s e q u a t i o n w ere e x p e c te d . is O th e r c o m b in a tio n s o f v a r i a b l e s w h ic h i n c l u d e d in c o m e p e r c a p i t a w e r e a l s o e x a m in e d , b u t th o s e e q u a t io n s d id n o t g iv e b e t t e r e s t i m a t e s . The p r i c e e l a s t i c i t y o f demand f o r c a t f i s h w as - 1 . 9 3 a t t h e m ean v a l u e . p ric e e la s tic ity C ro ss w i t h f i s h s t e a k s was 0 .2 4 ; and c r o s s p r i c e e l a s t i c i t y w ith b e e f w as 0 .2 1 . T h ese r e s u l t s w h ich g av e p o s i t i v e c r o s s e l a s t i c i t y f o r th e s u b s t i t u t e p r o d u c ts w ere e x p e c te d . v a lu e w as u s e d , th e n th e p r i c e e l a s t i c i t y I f t h e 1973-1982 a v e ra g e o f c a tfis h dem and d e c r e a s e d , s l i g h t l y t o - 1 . 1 8 , s t i l l i n th e e l a s t i c r a n g e . Alewif.e The dem and f u n c t i o n f o r a l e w i f e was e s ti m a t e d by e q u a tio n ( 6 . 5 ) . A l l s i g n s fro m t h e c o e f f i c i e n t s a tis fa c to ry . p a ra m e te rs in th is e q u a tio n w e re Q u a n tity o f a l e w i f e demanded h a s a n e g a t iv e r e l a t i o n s h i p w ith i t s own p r i c e . B e e f (PBD) h a s a c o m p le m e n ta r y r e l a t i o n s h i p w i t h 137 a le w if e r a t h e r th a n s u b s t i t u t e . co n su m e a l e w i f e i n d i r e c t l y T h i s i s d u e t o t h e f a c t t h a t hum ans t h r o u g h b e e f o r p o u l t r y s to c k s w h ich u s e a le w if e a s t h e i r fo o d . A le w if e h a s a n e g a t i v e r e l a t i o n s h i p w i t h t h e p ric e o f b e e f in t h i s case. P r i c e e l a s t i c i t y o f demand w as a - 0 .2 8 . C ro ss p r i c e e l a s t i c i t y w ith b e e f w as - 2 . 7 . h ig h a t 1 0 .8 . Income e l a s t i c i t y was f a i r l y A g a in , t h i s m ig h t b e c a u s e d by a n i n c r e a s e i n incom e w hich I n c r e a s e s th e demand f o r a le w if e a s fo o d f o r l i v e s t o c k , a s w e ll a s o th e r a n im a ls and p e t s . w h ic h y i e l d p o u ltry , I n s p i t e o f low R2 and D-W t e s t s i n c o n c l u s i v e r e s u l t s o n w h e th e r o r n o t t o accept th e h y p o t h e s i s o f no s e r i a l c o r r e l a t i o n i n th e e s t i m a t i o n , a l l t h e s i g n s o f t h i s e s t i m a t e w ere e x p e c te d . The c o e f f i c i e n t f o r a l e w i f e p r i c e i s not s i g n i f i c a n t a t th e .1 0 l e v e l . S u p p ly E s tim a tio n s As i n th e c a s e o f dem and e s t i m a t i o n , v a r io u s c o m b in a tio n s o f v a r i a b l e s w e re a l s o e x a m in e d i n e s t i m a t i n g t h e s u p p l y f u n c t i o n s o f w h ite fis h . E q u a tio n e s tim a te . ( 6 .6 ) The q u a n t i t y i n T a b l e V I-6 w as s e l e c t e d a s t h e b e s t o f w h ite fis h s u p p lie d has a p o s itiv e r e l a t i o n s h i p w ith th e d e f l a t e d p r i c e o f w h i t e f i s h , a s e x p e c te d . e x p e o te d t h a t th e p r ic e o f g a s o lin e c o e ffic ie n t, h o w e v e r, i t p r i c e o f la k e t r o u t have a n e g a tiv e tu rn e d o u t to be p o s itiv e . Even th o u g h th e (PTD) w as e x p e c t e d t o h a v e a n e g a t i v e s u b s titu te f o r w h ite fis h e x p la in e d . ( PGD) w o u ld t h e s i g n w as p o s i t i v e . I t was s ig n as a T h is r e s u l t c a n b e The f is h e r m e n c a t c h la k e t r o u t t o g e t h e r w ith w h i t e f i s h u s in g t h e sam e n e t s . T h i s w as g e n e r a l l y c o n s id e r e d an i n c i d e n t a l c a tc h when Table VI-6. The Eatiaated Supply Funotlona for Several Flab Speolea on Michigan Great Lakea Coaaarolal Plabery with Ordinary Leaat Squarea M<flriah QM « -5282190 (3.7) S2 * 0.98 ♦ 398017 FVD + 1751820 POD + 206017 PID ♦ 165.6 VTB ♦ 16433 «CPE (0.7) (4.1) (0.7) (7.4) (7.7) D-V « 1.44 (6.6) F > 192.5 Chuba QCH « 5100214 * 1081973 PCHD - 3259661 PCHD + 1765519 W D - 3685902 PPD - 607797 POD (1.3) (0.62) (2.7) " (1.3) (1.45) (0.35) R2 * 0.81 D-V * 1.81 F «14.4 Perch QP > 3106155 + 671583 PPD ♦ 23.2 PTE + 21273 POPE ♦ 1844737 PC1TD + 981975 (1.7) (0.74) (7.3) (3.7) (1.7) (1.6) R2 « 0.95 D-V * 2.47 POD - 397518 PCHD+0.035 QPM - 0.006 QPO (0.9) (0.6) (0.3) F «13.2 PCATD « 1.14 - 0.38 * 10-6 QCAT - 0.001 CACPE - 0.294 POD ♦ 0.32 x 10~7 QP♦ 0.43 * 10-5 CATE (12.2) (2.7) (1.0) (2.5) (1.77) R2 a 0.90 D-V . 1.85 0.60 D-V a 1.4 (6.9) F «31.7 Al fl Vl fC . a c t PALD a 0.066 ♦ 0.469 x 10 QAL - 0.0036 POD - 0.63 x 10~9 QALM - 0.368 x 10-5 ALCPB - 0.186 X 10 ALTB (2.2) (1.35) (0.13) (1.6) (2.6) (1.5) R2 a (6.7) ‘ Fa Note: Nuabera In parentheala are *ta valuta. 3.8 (6.10) (6.8) 139 g o v e rn m e n t r e g u l a t i o n b e g a n c o m m e r c ia l f i s h i n g . to re s tric t la k e tro u t c a tc h e s fo r The p o s i t i v e s ig n th e n , i s n o t r e a l l y u n e x p e c te d , s i n c e la k e t r o u t c o u ld a l s o b e c o n s id e r e d a s a com plem ent t o w h i t e f i s h . The p o s i t i v e s ig n s o f th e t o t a l e f f o r t e f f o r t (WCFE) p a r a m e te r s w ere e x p e c te d . (WTE) a n d c a t c h p e r u n i t o f T h is i n d i c a t e s t h a t w hen WCPE and WTE in c r e a s e d , th e number o f w h i t e f i s h c a u g h t a l s o i n c r e a s e s . e l a s t i c i t y o f s u p p ly o f w h i t e f i s h w as 0 .2 . o f s u p p l y w as 0 . 8 3 . P r ic e The t o t a l e f f o r t e l a s t i c i t y I n d i c a t i n g t h a t ea c h p e r c e n t i n c r e a s e i n f i s h i n g e f f o r t w i l l i n c r e a s e t h e f i s h c a u g h t by 0 .8 3 p e r c e n t. .Chub.? T he c h u b s u p p l y f u n c t i o n w as e s t i m a t e d by e q u a t i o n ( 6 . 7 ) . The q u a n t i t y o f f i s h s u p p lie d h a s a p o s i t i v e r e l a t i o n s h i p w ith i t s own p r i c e (PC H D ). The n e g a tiv e r e l a t i o n s h i p w ith th e p r i c e o f g a s o l i n e (PGD) and p r i c e o f th e p e rc h (PPD) w ere e x p e o t e d , b u t n o t s o w i t h t h e n e g a t i v e s i g n o f a o n e y e a r l a g i n t h e p r i c e o f c h u b s a n d a p o s i t i v e s ig n o f p r i c e o f w h i t e f i s h (FWD). P r ic e e l a s t i c i t y o f ch u b s was 0 .2 3 u s i n g t h e m ean v a l u e b u t i n o r e a s e d t o used. 0 .7 6 i f th e 1 9 7 3 -1 9 8 2 a v e ra g e v a lu e was C ro s s e l a s t i c i t y o f s u p p ly w ith p e rc h w as - 0 .7 4 . in c re a s e d s u b s ta n tia lly T h is m a g n itu d e t o > 2 .3 8 ( i n a b s o l u t e v a l u e ) i f t h e 1973-1982 a v e ra g e v a lu e was u s e d . Jtereh E q u a tio n ( 6 .8 ) was th e e s ti m a t e o f s u p p ly f u n c t i o n f o r p e r c h . Most o f th e s ig n s f o r p a ra m e te r c o e f f i c i e n t s i n t h i s e s t i m a t e w e r e e x p e c t e d e x c e p t f o r th e p r i c e o f g a s o l i n e (PGD) and t h e p r i c e o f c a t f i s h d e f l a t e d 140 (PCATD). The p r i c e e l a s t i c i t y e l a s t i c i t y w ith ch u b s w as - 0 .2 8 . o f s u p p ly w as 0 .4 4 . C ro ss p ric e T o ta l e f f o r t e l a s t i c i t y was 0 .6 7 * C a tfis h The s u p p ly e x p e c ta tio n . fu n c tio n e s tim a te f o r c a t f is h V a rio u s c o m b i n a t i o n s d id n o t s a t i s f y o f v a ria b le s any w e re e x a m in e d , u n f o r t u n a t e l y none y i e l d e d a p o s i t i v e l y s lo p e d s u p p ly c u r v e . One o f th e e x a m p le e q u a t i o n s u s e d t o e s t i m a t e c a t f i s h s u p p ly i s p re s e n te d in e q u a tio n ( 6 .9 ) * A le w ife T he b e s t e s t i m a t i o n f o r th e s u p p ly f u n c t i o n o f a le w i f e i s shown i n e q u a tio n ( 6 . 1 0 ) , a lth o u g h o n ly a b o u t s i x t y p e r c e n t o f t h e v a r i a t i o n i n th e q u a n tity o f a l e w i f e s u p p l i e d w as e x p l a i n e d by t h e i n d e p e n d e n t v a r ia b le s (th e r e g r e s s o r s ) . oan be used to P r i c e f l e x i b i l i t y o f s u p p l y w as 0 .6 w h ic h a p p ro x im a te th e e l a s t i c i t y o f s u p p l y by t a k i n g t h e i n v e r s e o f t h i s f l e x i b i l i t y c o e f f i c i e n t w hich r e s u l t s i n a m a g n itu d e o f 1 .6 7 . E x cep t a le w ife , a l l c o e f f i c ie n t s f o r p r ic e s o f w h ite f is h , chubs, and p e rc h a r e n o t s i g n i f i c a n t a t th e .1 0 l e v e l . E s tim a te s P s in g S im u lta n e o u s E q u a tio n s Method S e v e r a l te c h n iq u e s from s im u lta n e o u s e q u a tio n m eth o d s w ere u s e d t o e s t i m a t e demand and s u p p ly o f co m m ercial f i s h e r i e s i n M io h ig an . Reduced Form I n s i t u a t i o n s w here th e s y s te m o f demand and s u p p l y e q u a t i o n s f o r each f is h s p e c i e s w as J u s t i d e n t i f i e d , t h e re d u c e d fo rm te c h n iq u e was u s e d t o e s t i m a t e th e s t r u c t u r a l p a ra m e te rs o f dem and a n d s u p p l y . T h is m ean s t h a t e v e r y e n d o g e n o u s v a r i a b l e (d e p e n d e n t v a r i a b l e ) i s e x p r e s s e d a s a f u n c t i o n o f a l l e x o g e n o u s v a r i a b l e s i n th e s y s te m . T hus, no e n d o g e n o u s v a r i a b l e s a p p e a r a s t h e in d e p e n d e n t v a r i a b l e s . Each re d u c e d fo rm e q u a t i o n w as e s t i m a t e d by o r d i n a r y l e a s t s q u a r e s (O L S ). The e s t i m a t e s o f t h e re d u c e d form p a r a m e te r s w ere th e n c a l c u l a t e d t o o b ta in th e e s t i m a t e s o f th e s t r u c t u r a l p a r a m e te r s ( o r i g i n a l dem and a n d s u p p l y fu n c tio n s ). T he e s t i m a t e d o r i g i n a l dem and and s u p p ly f o r w h i t e f i s h , p e rc h and c a t f i s h a s w e l l a s re d u c e d fo rm e q u a t i o n s , a r e p r e s e n t e d i n T a b le V I - 7 . The e s t i m a t e s f o r w h i t e f i s h demand- and s u p p ly f u n c t i o n s i n e q u a t i o n s ( 6 . 1 3 ) a n d ( 6 . 1 4 ) w e r e d e r i v e d fro m e q u a t i o n s 6 .1 2 ). The e s tim a te d dem and ( 6 .1 3 ) g iv e s a l l t h e e x p e c te d s i g n s w ith r e g a r d t o p r i c e and in co m e. a n e g a tiv e ly ( 6 . 1 1 ) an d H owever, t h e s u p p ly e q u a tio n ( 6 .1 4 ) y i e l d s s lo p e d c u rv e w ith r e s p e c t to i t s own q u a n t i t y . O th er c o m b in a tio n s o f v a r i a b l e s w ere a l s o ex am in ed , b u t m o s t y i e l d e d s i m i l a r re s u lts . T he e s t i m a t e f o r c h u b s u s i n g t h e r e d u c e d form te c h n iq u e d i d n o t g iv e s a t i s f a c t o r y * r e s u l t s . U sin g t o t a l e f f o r t and d e f l a t e d in c o m e p e r c a p i t a a s p r e d e t e r m i n e d v a r i a b l e s g av e a p o s i t i v e s lo p e o f demand and n e g a tiv e s lo p e o f s u p p ly in th e o r i g i n a l s t r u c t u r a l e q u a tio n , o p p o s ite e q u a tio n s of w hat w as e x p e c te d . ( 6 .1 5 ) ; ( 6 .1 6 ) ; th e T he e s t i m a t e f o r p e r c h , s e e n i n ( 6 .1 7 ) ; and ( 6 .1 8 ) , d id n o t g iv e a T able V I-7. The E stim a te d Demand and Supply F u n c tio n s f o r S e v e ra l F ish S p e c ie s U sing th e Reduced Form Method W h ite fis h Reduced Form QW = -528197 - 1010032.7 ™Dt « + 1114.26 DICD PWD = 3 .1 2 + 0.1235 PW D ^ - o7000229 DICD (6 .1 1 ) (6 .1 2 ) atr-Ms t -ural . EflM.tJ-.an Demand QW=30801811 - 8178402 PWD + 3028 DICD Supply PWD=-2 .0 1 - 2.1 x 10~7 QW + 0.336 PW D ^ (6 .1 3 ) (6 .1 4 ) P erch Reduced Form QP = 6262198 - 413143 PPD . - 602.2 DICD PPD = -0.3 4 1 + 0.327 MDt - 1 “ + 0.9 3 8 x 10 (6 .1 5 ) (6 .1 6 ) DICD StE-us.tur a l . EauflU.on Demand QP=5831367 - 1263434 PPD - 483.6 DICD Supply PPD=-0 .6 3 6 - 0.156 x 10"6 QP + 0.2 6 3 PPDt- 1 (6 .1 7 ) (6 .1 8 ) C a tf is h Reduced Form QCAT = -497264 + 3 .6 7 2 CATE + 90.82 DICD PCATD = 1.573 - 0.3 2 4 x 10"5 CATE - 0.9 4 9 x 10 . DICD S t m s t o r a l E q u atio n Demand QCAT = 1285469 - 1133333 PCATD - 16.71 DICD Supply PCATD s 1.053 - 0.1045 x 10"5 QCAT + 0.596 x 10 (6 .1 9 ) (6 .2 0 ) CATE (6 .2 1 ) (6 .2 2 ) 143 s a t i s f a c t o r y r e s u l t e x c e p t f o r th e q u a n t i t y p r i c e r e l a t i o n s h i p demand e q u a t io n o f t h e s t r u c t u r a l form ( 6 . 1 7 ) . y ie ld s u n s a tis f a c to r y r e s u l t s a l s o . in th e The e s t i m a t e f o r c a t f i s h None o f t h e e s t i m a t e s g a v e t h e e x p e c te d s i g n s a s shown i n e q u a t io n s ( 6 .2 1 ) and ( 6 .2 2 ) . A lth o u g h demand e s t i m a t e s g av e a n e g a tiv e s lo p e o f t h e demand o u r v e , a n e g a t i v e s i g n o n in c o m e p a r a m e t e r s w as n o t e x p e c t e d . O th e r c o m b in a tio n s o f v a r i a b l e s w ere a l s o ex am in ed , b u t none o f th e e s t i m a t e s g av e a b e t t e r r e s u l t . Due t o th e l i m i t a t i o n s o f t h e d a t a and in f o r m a tio n on a le w if e s p e o i e s , t h e r e w as no s im u lta n e o u s e q u a tio n m ethod exam ined f o r a l e w i f e . lAflir-g.o.t. Lg.agJL.S.q.uar.3a T he e s t i m a t e o f dem and a n d s u p p ly f u n c t i o n s u s in g i n d i r e c t l e a s t s q u a r e s (IL S ) te c h n iq u e w as o b ta in e d by i n s e r t i n g t h e e s t i m a t e s o f t h e p a ra m e te rs fro m t h e r e d u c e d fo rm i n t o s tr u c t u r a l e q u a tio n s . T he en d o g en eo u s (d e p e n d e n t) v a r i a b l e c o e f f i c i e n t s e s t i m a t e d i n t h e r e d u c e d fo rm w e re s u b s t i t u t e d i n t o th e s t r u c t u r a l e q u a t io n s ; th e n th e p a ra m e te r c o e f f i c i e n t s from th e s t r u c t u r a l e q u a tio n s o o u ld be e s ti m a t e d . U nder j u s t - i d e n t i f i e d dem and a n d s u p p l y , e s tim a te s u s in g c o n d itio n s a s used in th e e s tim a tio n o f IL S t e c h n i q u e g a v e a r e s u l t e q u i v a l e n t th e to Two S t a g e L e a s t S q u a r e s ( 2S L S ) m e th o d . th e The d i f f e r e n c e s i n th e p a ra m e te r c o e f f i c i e n t s b e tw e e n t h e e s t i m a t e s u s i n g t h e s e tw o m e th o d s w as c a u s e d by a ro u n d in g e r r o r su c h a s shown b etw ee n e q u a tio n s ( 6 .2 3 ) a n d ( 6 . 2 4 ) , w h ic h r e p r e s e n t s t h e dem and a n d s u p p l y e s t i m a t e s f o r p e r c h , w ith e q u a t io n s ( 6 .3 1 ) and ( 6 .3 2 ) , t o b e p r e s e n te d below . QP = 5831873 - 1263433 PPD - 4 8 3 .7 DICD ( 6 .2 3 ) PPD = 0 .6 3 5 - 0.1 5 6 x 10"6 QP + 0 .2 6 3 ( 6 .2 4 ) T h e r e f o r e , t h i s s tu d y p r e s e n t s o n ly th e e s t i m a t e s u s in g 2SLS m ethod w ith th e j u s t - i d e n t i f i e d c a se . Two and T h re e S ta g e L e a s t S q u a re s (2SLS and 3SLS) U nder t h e j u s t - i d e n t i f i e d c o n d i t i o n , e s t i m a t i o n u s in g two and t h r e e s ta g e l e a s t s q u a r e s te c h n iq u e s g a v e i d e n t i c a l r e s u l t s . and ( 6 .2 6 ) w h ite fis h E q u a tio n s ( 6 .2 5 ) i n T a b l e V I - 8 a r e t h e dem and a n d s u p p l y e q u a t i o n s e s t i m a t e d by 2SLS an d 3SLS. fo r A n o th e r c o m b in a tio n , su ch a s e q u a tio n s ( 6 .2 7 ) and ( 6 . 2 8 ) , u s e d incom e p e r c a p i t a an d t o t a l e f f o r t a s th e exogeneous v a r ia b le s . s lo p e d s u p p ly c u r v e s . B o th o f t h e s e e s t i m a t e s g a v e n e g a t i v e l y The dem and f u n c t i o n , a s e s tim a te d by e q u a tio n ( 6 . 2 5 ) i g a v e s a t i s f a c t o r y r e s u l t s w h ere th e d e f l a t e d p r i c e o f w h i t e f i s h c o e f f i c i e n t h ad a n e g a tiv e s ig n an d t h e d e f l a t e d p r i c e o f la k e t r o u t , a s s u b s titu te fo r w h ite fis h , had a p o s itiv e s ig n . H o w e v e r, dem and e s tim a te d by e q u a t i o n ( 6 .2 7 ) d id in c o m e The e s ti m a t e o f chub demand and s u p p ly , a s shown i n p a ra m e te r. n o t g iv e th e e x p e c te d s ig n f o r th e e q u a tio n s ( 6 .2 9 ) and ( 6 . 3 0 ) , g av e th e e x p e c t e d r e s u l t f o r d em an d , b u t n o t f o r s u p p ly . The s u p p l y f u n c t i o n h a s a n e g a tiv e s l o p e . The same r e s u l t s w ere o b t a i n e d i n t h e e s t i m a t i o n o f t h e dem and a n d s u p p l y o f p e r c h an d c a t f i s h ( 6 .3 4 ) . a s show n i n e q u a t i o n s ( 6 .3 1 ) » ( 6 . 3 2 ) , (6 .3 3 )> and The s u p p ly f u n c t i o n s f o r b o t h s p e c i e s h a v e n e g a t i v e s l o p e s . In co m e p a r a m e t e r s i n b o t h dem and e q u a t i o n s g a v e u n e x p e c te d s ig n s . n e g a tiv e f a b l e V I-8 . H h ltg f is h Demand Supply Demand Supply The E stim ated Demand and Supply F u n c tio n s f o r S e v e ra l F is h S p e c ie s U sing Two and Three S ta g e L e a st S q u ares (2SLS and 3SLS) Method (W ith J u s t - I d e n t i f i e d C ase) QW=12139038 - 14712698 PWD + 7048540 PTD PWD=1.85 - 0.221 x 10- 6 QW + 0 .6 5 4 x 10"6QT (6 .2 5 ) (6 .2 6 ) QW=16572644 - 7096133 PWD - 498.6 DICD PWD=1 .7 - 0.258 x 10 QW + 0.266 x 10 WTE (6 .2 7 ) (6 .2 8 ) Chubs Demand PCHD = 0.734 - 0.474 x 10~7 QCH+ 1.06 PHD Supply QCH = 4187284 - 6585434 PCHD + 2549048 PWD (6 .2 9 ) (6 .3 0 ) P erch Demand Supply (6 .3 1 ) (6 .3 2 ) QP=5831797 - 1263567 Pj?D - 483.6 DICD PPD=0 .6 3 5 - 0.156 x 10"6 QP + 0 .2 6 3 PPD. , t* l C a tf is h Demand QCAT = 1344684 - 1175357 gCATD - 20.1 DICD Supply PCATD s 1 .1 5 - 0.109 x 10"5 QCAT - 0.107 PCATD. , V -1 (6 .3 3 ) (6 .3 4 ) A dding m ore v a r i a b l e s i n t o th e j u s t - i d e n t i f i e d e q u a t i o n sy stem w i l l o r e a t e an o v e r - i d e n t i f i o a t i o n o a s e w h ich c a n b e e s t i m a t e d b y 2SLS a n d 3SLS t e c h n i q u e s . S im ila r r e s u l t s in p a r a m e te r c o e f f i c i e n t e s t i m a t e s w e re o b t a i n e d fr o m t h e 2SLS a n d 3SLS t e c h n i q u e s , m a g n itu d e s o f t h e p a r a m e te r c o e f f i c i e n t s . th e T h e re w e re no d i f f e r e n c e s i n th e s ig n s o f c o e f f i c i e n t s betw een th e s e two e s t i m a t e s . th re e ex cep t fo r H o w e v e r, s in c e s t a g e l e a s t s q u a r e s e s t i m a t o r s a r e m ore e f f i c i e n t th a n 2SLS, o n ly 3SLS w i l l be p r e s e n te d I n t h i s s tu d y . p e rc h and c a t f i s h , a l l From t h e e s t i m a t e s , e x c e p t f o r s p e c i e s h a v e p o s t i v e l y s lo p e d s u p p ly f u n c t i o n s a s c a n be s e e n i n t h e r e s u l t s o f e q u a t i o n s (T a b le V I-9 )* ( 6 .3 6 ) , ( 6 .3 8 ) , and ( 6 .4 4 ) M o r e o v e r , t h e c o e f f i c i e n t s f o r p r i c e o f w h i t e f i s h and q u a n t i t y o f a le w i f e i n th e s u p p ly f u n c t i o n s a r e s i g n i f i c a n t a t t h e le v e l. .0 5 T he c o e f f i c i e n t o f ch u b p r i c e , h o w ev er, i s n o t s i g n i f i c a n t a t th e .1 0 l e v e l , a lth o u g h i t w as more s i g n i f i c a n t t h a n t h a t e s t i m a t e d by th e s in g le e q u a t i o n m e th o d . T he e s t i m a t e s u s i n g t h e f o u r e q u a t i o n sy ste m f o r w h i t e f i s h and c a t f i s h a s show n i n e q u a t i o n s ( 6 .5 2 ) in T a b le V I-1 0 d id n o t g iv e ( 6 .4 5 ) th r o u g h e x p e c te d r e s u l t s . P o s itiv e r e l a t i o n s h i p s b etw een t h e p r i o e a n d q u a n t i t y i n t h e s u p p l y f u n c t i o n s w e re n o t o b t a i n e d fr o m t h e s e e s t i m a t e s . The e s t i m a t e s u s in g 2SLS and 3SLS d i d n o t show R2 b e c a u s e R2 i s n o t m e a n in g fu l in t h i s m e th o d , and SPSS d o e s n o t e s t i m a t e R2 v a lu e s f o r 2SLS and 3SLS. O nly th e s i n g l e e q u a tio n and 3SLS m e th o d s g a v e p o s i t i v e l y s u p p ly f u n c t i o n s f o r w h i t e f i s h , c h u b s , and a l e w i f e s p e c i e s . s lo p in g The r e a s o n s t h a t th e o t h e r m ethods d i d n o t g iv e th e e x p e o te d r e s u l t s a r e n o t c l e a r , d e s p i t e th e f a c t t h a t th e v a r i a b l e s h a v e b e e n s p e c i f i e d a c c o r d in g t o th e b e s t a v a i l a b l e in f o r m a tio n . The r e s u l t s c a n b e c a u se d by f a c t o r s o t h e r t h a n c o s t s an d p r i c e s t h a t a f f e c t e d t h e a v a i l a b i l i t y o f f i s h , b u t w ere T ab le V I-9 . The E stim a te d Demand and Supply F u n c tio n s f o r S e v e ra l F is h S p e o ie s U sing Two and T h ree S ta g e L e a s t S q u ares (2SLS and 3SLS) Method (W ith O v e r - I d e n tifie d Case) fflilteflsh Demand QW = Supply QW = Chubs Demand QCH = Supply QCH = Peroh Demand QP = Supply QP = 9528834 - 5708355 PWD + 297356 PSD - 1859269 PFID + 730443 PBD + 286 DICD ( 2 .1 ) ( 4 .4 7 ) ( 3 .4 ) ( 1 .5 6 ) (4 .9 7 ) 117745 ♦ 615967 PWD - 1739062 PTD + 777583 PGD + 5633 WCPE + 1 8 5 WTE (3 .8 6 ) (2 .1 9 ) (1 .1 9 ) ( 6 .0 9 ) (1 .9 4 ) (1 .9 3 ) 6481854 - 4186541 PCHD + 4328013 PBD + 3934575 PCFD - 1594 DICD (2 .1 9 ) ( 3 .4 7 ) (2 .7 4 ) (2 .7 7 ) (5 .7 5 ) 5835477 + 3960452 PCHD - 4484195 PCHD, t- 1 + 1080317 PWD - 6167263 PPD (1 .7 1 ) ( 1 .2 5 ) (2 .5 9 ) ( 6 .6 7 ) (1 .7 8 ) 3314867 - 3798355 PPD + 298287 PSD - 93473 PSCD (6 .5 8 ) ( 1 .7 7 ) (3 .4 1 ) (4 .6 8 ) 2835116 - 375580 PPD + 384429 PCATD + 2608343 PGD (3 .9 5 ) ( 1 .4 4 ) (8 .1 1 ) (1 .1 9 ) (6 .3 5 ) (6 .3 6 ) (6 .3 7 ) (6 .38 ) (6 .3 9 ) (6 .4 0 ) Catfish Demand QCAT = Supply QCAT = 795647 - 879162 PCATD + 28702 PSTD + 80076 PBD ( 2 .5 ) (4 .4 2 ) (8 .2 8 ) (7 .8 3 ) 2010226 - 1653290 PCATD - 189960 PPD - 365003 PGD ( 1 .5 ) ( 1 .8 ) ( 7 .1 9 ) (7 .2 3 ) (6 .4 1 ) (6 .4 2 ) AlfiKlfe Demand QAL 2204931100 - 30611176 PALD - 7315562 PBD + 5516 DICD - 1135008 YEAR ( 3 .7 ) ( 4 .4 ) ( 9 .6 ) ( 2 .6 ) (3 .6 5 ) Supply PALD — 0.0 6 + 0 .1 9 8 x 10**8 QAL - 0.0 0 8 PGD - 0 .3 2 x 10-5 ALCPE - 0.51 x 10“ 9 QALM (1 .2 7 ) N ote: ( 2 .1 ) Numbers i n p a r e n th e s is a r e " t ” v a lu e s . ( 3 .3 ) (1 .9 5 ) (1 .5 1 ) (6 .4 3 ) (6 .4 4 ) Table VI-10. The Estimated Demand and Supply Functions fo r Several Fish Species Using Two and Three Stage Least Squares (2SLS and 3SLS) Method (With Four-Equation Systems). MUUefiah Three Stage Least Souares Demand QU = 13076628 - 11531108W D ♦ 0629500 PTD * 1209067 PFID - 007.2 DICD Supply W D = 1.89 - 0.216 * 10~6 QU + Demand QT = 2202089 ♦ 082383 PTD - 1260059PUD - 126.9 (6.05) 0.378x 10-6 QT ♦ 0.263 x 10~3 UCPE ♦ 0.109 POD (6.06) DICD ♦ 02020 PCATD (6.07) (6.08) S a tn a h Three Stage Least Souares Demand QCAT * 1398813 - 1163708 PCATD - 170030 W D - 68.8 DICD ♦ 167339 PTD ♦232326 PFID (6.09) Supply PCATD = 1.07 - 0.010 x 10-6 QCAT + 0.521 x 10~7 QP - 0.17 POD - 0.0017 CACPE - 0.62 x 10"5 QCAM Demand QU = 11302719 - 5695366 W D ♦ 269 DICD - 135781 PTD - 2886799 PFID Supply PPD = 1.06 - 0.397 x ID’7 QP ♦ 0.113x 10-5 QCAT - 0.368 x 10-7 QCH - + (6.50) 0307978 PCD(6.51) 0.377 POPE- 0.61 PGD(6.52) 148 Supply PTD = 1.82 ♦ 1135580 QT *25062299 QU + 0.137 PGD ♦ 0.129 x 10-7QCH 149 n o t in c o r p o r a te d i n t o t h e m odel. T h ere a r e many s t r u c t u r a l c h a n g e s i n t h e M ic h ig a n G re a t L akes com m ercial f i s h e r i e s sy stem w hich c o u ld n o t be a c c o m o d a te d i n t o p o llu tio n t h e m o d e l. E n v i r o n m e n ta l c h a n g e s su ch a s w a te r b y DDT, PCB, m e rc u r y an d o t h e r p o l l u t a n t s c o u l d n o t b e s p e c i f i e d e x p l i c i t l y i n th e m o d e l. T h e re fo re , it i s n o t p o s s ib le to o s b e r v e w h a t e f f e c t s th e s e ch an g e s w ould h av e on th e s u p p ly and demand o f com m ercial f i s h e r i e s . P u b lic p o l i c y and r e g u l a t i o n s a l s o c o u ld n o t b e i n c o r p o r a t e d i n t o t h e m o d e l, a lth o u g h th e s e f a c t o r s a r e b e l i e v e t o h av e a s tr o n g i n f l u e n c e on t h e com m ercial f i s h s u p p ly a n d d em an d . m odel i n t h i s The s tu d y a n a ly z e d th e o v e r a l l ( a g g r e g a te ) e f f e c t s o f a l l t h e s e f a c t o r s on demand and s u p p ly w ith o u t d i s a g g r e g a t i n g th e i n d i v i d u a l e f f e c t o f each f a c to r . T h e re is a ls o a p o s s ib ility com m ercial f i s h e r i e s m ig h t a c t u a l l y t h a t th e s u p p ly c u rv e s o f th e s e s l o p e b a c k w a r d s , a s d i s c u s s e d by C r u t c h f i e l d and P o n te c o rv o , 1969; C opes, 1970; and C la r k , 1976. In th is c a s e , th e e s ti m a t e d s u p p ly c a n be p o s i t i v e i n t h e l o w e r p o r t i o n o f t h e s u p p ly c u r v e , and n e g a t iv e i n th e h ig h e r p o r t i o n o f t h e s u p p ly c u rv e . E l a s t i c i t i e s and F l e x i b i l i t i e s P r i c e e l a s t i c i t y o f demand c a n b e d e f in e d a s th e p e r c e n ta g e change in q u a n tity r e s u ltin g P ric e -q u a n tity fro m fle x ib ility , a g iv e n p e rc e n ta g e change in p ric e . o n t h e o t h e r h a n d , sh o w s th e p e r c e n ta g e ohange i n p r i c e r e s u l t i n g from a g iv e n p e r c e n t c h a n g e i n t h e q u a n t i t y ( g i v e n t h a t t h e e f f e c t s o f o t h e r v a r i a b l e s on p r i c e re m a in c o n s t a n t ) . P r i c e f l e x i b i l i t y i s o f t e n t r e a t e d a s th e in v e r s e o f e l a s t i c i t y . (1 9 7 6 ) and G h a n b a ri (1 9 7 7 ) C a to I n t h e i r s t u d i e s u se d t h e in v e r s e o f p r i c e e l a s t i c i t y ( p r i c e f l e x i b i l i t y ) t o a p p ro x im a te p r i c e f l e x i b i l i t y (p ric e 150 e la s tic ity ). re la tio n s h ip T h e re i s fro m a n a d v a n t a g e t o e x a m in in g t h e p r i c e q u a n t i t y d if f e r e n t a s p e c ts , su o h a s by a p p ro x im a tio n o f p r i o e - e l a s t i o i t i e s from th e p r i c e - q u a n t i t y fle x ib ilitie s . T h is w ill a f lo w m e a su re m e n ts and c o m p a ris o n s o f th e e f f e c t on to t e d re v e n u e s from p r o d u o tio n i n c r e a s e s and d e c r e a s e s t o be made. On t h e o t h e r h a n d , t o know t h e p r i c e f l e x i b i l i t y c o e f f i c i e n t w i l l a l s o b e im p o r ta n t f o r c e r t a i n p r o d u c ts t h a t by t h e i r b i o l o g i c a l n a t u r e a re fix e d in s u p p ly , suoh a s c e r t a i n a g r i c u l t u r a l and f i s h p r o d u c ts . F o r th e s e p r o d u c ts th e im p o r ta n t in f o r m a tio n i s th e e f f e o t s o n p r i c e o f g iv e n p r o d u o tio n l e v e l s . H ence, in t h i s s tu d y , r e l a t i o n s h i p s ( e l a s t i o i t i e s and f l e x i b i l i t i e s ) T a b le V I-1 1 , a ll e la s tio itie s t h e i n v e r s e s o f th e a re a ls o s u p p ly e l a s t i o i t i e s . In a n d f l e x i b i l i t i e s w h ic h h a v e b e e n e s ti m a t e d from th e s i n g l e e q u a tio n m odel a r e sum m arized. be n o te d t h a t v e r y l i t t l e e m p lo y e d . I t s h o u ld a l s o s i g n i f i c a n c e oan b e fo u n d i n th e e s t i m a t i o n o f M ost o f t h e s e e s t i m a t e s a r e d e r i v e d fro m t h e p a r a m e t e r o o e f f i o i e n t s w h ic h h av e v e r y low t v a l u e s a s shown i n T a b le V I-6 . Demand e l a s t i o i t i e s on th e o t h e r h a n d , e x c e p t f o r a l e w i f e , w e re d e riv e d fro m th e c o e f f i c i e n t s w h ic h h a d h i g h t v a l u e s , w i t h t h e s i g n i f i c a n c e l e v e l s w ere b etw ee n .01 and .1 0 . T h e v a r i o u s e s t i m a t i o n s o f dem and e l a s t i c i t y o o e f f i o i e n t s on w h i t e f i s h and o a t f i s h show t h a t u s in g d i f f e r e n t a v e ra g e v a l u e s r e s u l t e d in d i f f e r e n t e l a s t i c i t y c o e ffic ie n ts . v a lu e g av e l a r g e r e l a s t i o i t i e s . U sin g lo n g e r p e r io d s o f a v e ra g e C o n v e r s e ly , f o r c h u b s a n d p e r c h , t h e lo n g e r th e p e rio d o f a v e ra g e v a lu e u s e d , c o e ffic ie n ts . t h e s m a l l e r th e e l a s t i c i t y T h i s m ig h t o c c u r b e c a u s e b o th co m m o d ity g r o u p s h a d d if f e r e n t tre n d s in p r o d u c tio n and p r i c e . W h ite f is h and c a t f i s h had i n c r e a s i n g t r e n d s i n p ro d u o tio n and d e c r e a s i n g t r e n d s i n p r i c e , w h i l e Table VI-11. Demand and Supply E la s tic itie s fo r Several Fish Species from M lchiga'sn Great Lakes Metnod Whitefish Demand Supply Elasticities/Flexibilities Chubs Perch Catfish Demand Supply Demand Supply Demand Supply Alewife Demand Supply Sinxle Eauatlon Method Price Elasticity 1973-1982 Average Value 1982 Value -2.38 -1.2k -0.43 Income Elasticity 1973-1982 Average Value 1.h 0.6 0.2 0.11 --- -0.51 -1.66 -0.80 -4.125 0.44 2.30 1.48 Canned Fish Cross Price Elasticity 1.34 Perch Cross Price Elasticity 0.21 -0.28 1.66* -2.7 o.k 0.18 -0.28 Steaks Cross Price Elasticity 0.24 Price Flexibility Note: ----- -0.74 Chubs Cross Price Elasticity Total Effort Elasticity -1.93 -1.18 10.8 Beef Cross Price Elasticity Shrimp Cross Price Elasticity t 0.23 0.76 5.0* --- 0.83 4.34* 2.27* --- 0.67 ■Elasticities/Flexibilities which are approximated by the Inverse of price flexlbllltles/prlce elasticities. Unless specified, all values are calculated at mean values. 0.60 152 c h u b s an d p e r c h h a d i n c r e a s i n g t r e n d s i n p r i c e an d d e c r e a s i n g t r e n d s i n p ro d u c tio n . T h is s i t u a t i o n m ig h t h a v e s h i f t e d t h e e q u i l i b r i u m p o i n t o f w h ite fis h and c a t f i s h to th e le s s e la s tic p a r t o f t h e d em an d c u r v e ( F ig u r e s IV -2 and I V - 8 ) , w h ile c h u b s an d p e r c h s h i f t e d e la s tic p a r t o f th e dem and cu rv e (F ig u re s I V - l) a n d to t h e m ore IV -6 ). The m a g n itu d e s o f t h e demand an d s u p p ly e l a s t i c i t i e s w h ich w e re e s t i m a t e d by t h e 3SLS m eth o d a r e shown i n T a b le V I-1 2 . The demand p r i c e e l a s t i c i t i e s e s t i m a t e d th r o u g h 3SLS y i e l d e d l a r g e r c o e f f i c i e n t s th a n t h o s e e s t i m a t e d u s i n g t h e s i n g l e e q u a t i o n m eth o d , e x c e p t f o r a l e w i f e . s u p p ly p r i c e e l a t i c i t y S im ila rly , c o e f f i c i e n t s e s t i m a t e d b y 3SLS a l s o th e y ie ld e d h i g h e r s u p p ly e l a s t i c i t i e s . M o st o f t h e s u p p ly p r i c e e l a s t i c i t i e s w e re lo w o r i n e l a s t i c . m ig h t i n d i c a t e t h a t th e fis h e rm e n re s p o n s iv e to m a rk e t p r ic e ch an g es. fis h e rm e n h a v e b e e n r e s p o n d in g t o p ric e . (fis h e ry in d u s try ) a re n o t v e ry T h is i m p l i e s t h a t t h e c o m m ercial th e a v a ila b ility of fis h , T h e r e f o r e , f is h e r m e n h a v e f u n c t i o n e d a s p r i c e t a k e r s . n o t to G h a n b a ri (1 9 7 7 ) a l s o i n d i c a t e d t h i s s u p p o s i t i o n i n h i s s tu d y o n w h i t e f i s h G re a t L a k e s, a s d id C a to (1 9 7 6 ) T h is in h is in th e s t u d y o f m u l l e t f is h e r m e n i n F lo rid a . S o c i a l S u r p lu s (N e t a l l - o r - n o n e V a lu e ) o f S e v e r a l F is h S p e c i e s ■frgin. MJ-shlKan .Qpmmsrslal Fivhsrteg " S o c ia l s u r p l u s " ( n e t a l l - o r - n o n e v a l u e ) i s d iv i d e d i n t o tw o p a r t s : consum er s u r p l u s and p r o d u c e r s u r p l u s . The "co n su m er s u r p l u s " is th e n e t a d v a n t a g e o f c o n su m e rs a b l e t o b u y a c e r t a i n u n i t o f a com m odity a t th e e q u i l i b r i u m p r i c e P *, w hen t h e y a r e w i l l i n g to pay h ig h e r p r ic e s T a b le V I-1 2 . Demand and S upply E l a s t i c i t i e s f o r S e v e r a l F is h S p e c ie s from M ic h ig a n 's G re a t L akes (E s tim a te d by 2SLS and 3SLS M ethods) Method W h ite fis h Demand S upply Chubs Demand S u pply S im u lta n e o u s Eqva.tj-PJL!4§IlL£><3 P r ic e E l a s t i c i t y - 2 .8 9 - 0 .9 0 Income E l a s t i c i t y 0 .8 9 B eef C ro ss P r ic e E la s tic ity 0 .3 2 Canned F is h C ro ss P r ic e E l a s t i c i t y P erch C ro ss P r ic e E la s tic ity Shrim p C ro ss P r ic e E la s tic ity 0 .1 3 Chubs C ro ss P r ic e E la s tic ity T ro u t C ro ss P r ic e E la s tic ity S te a k s C ro ss P r ic e E l a s t i c i t y T o ta l E f f o r t E la s tic ity P r ic e F l e x i b i l i t y 0.31 0 .8 5 E la s tic itie s /F le x ib ilitie s P erch C a t f is h Demand S upply Demand S upply -2 .5 1 - 1 .9 6 A lew ife Demand S upply - 0 .2 4 4 .0 " 1 0 .9 1.6 - 2 .0 0 .2 9 2 .4 2 - 1 .2 4 , 0 .3 6 - 0 .9 8 0.21 0 .9 3 3 .2 3 " 1 .1 8 " 0 .2 5 N ote: " E l a s t i c i t i e s o r F l e x i b i l i t i e s w hich a r e ap p ro x im ate d by th e in v e r s e o f p r i c e f l e x i b i l i t i e s o r p ric e e l a s t i c i t y . 154 ( H i r s h l e i f e r , 1 9 7 6 ). The consum er s u r p l u s I s a n a r e a l y i n g b e n e a t h t h e d em an d c u r v e D b u t a b o v e th e h o r i z o n t a l l i n e th r o u g h e q u i l i b r i u m p r i c e P *. T he " p r o d u c e r s u r p l u s " , on th e o th e r h a n d , i s th e n e t g a in to p r o d u c e r s a b l e t o s e l l a t p r i c e s a s h ig h a s P* when th e y w ould h a v e b e e n w i l l i n g t o s e l l a s m a l l e r num ber o f c o m m o d itie s a t l o w e r p r i c e s . p ro d u c e r s u rp lu s i s ( s e e F ig u r e V I - 1 ) . consum er s u r p lu s v a lu e o f s o c ia l th e a r e a l y i n g ab o v e s u p p ly c u rv e S b u t b elo w ?*B The a r e a ABCO i s th e s o c ia l s u rp lu s : t h e sum o f ( a r e a ABP*) a n d p r o d u c e r s u r p l u s ( a r e a P»BCO). s u rp lu s T he The c a n be e s t i m a t e d e i t h e r by a g e o m e tr ic or c a lc u lu s a p p ro a c h . tfM t.gf.l9h S in c e th e e s tim a te s of t h e d em an d a n d s u p p l y w e r e l i n e a r , a g e o m e tr ic a p p r o a c h w i l l b e u s e d t o m e asu re t h e v a l u e s o f s o c i a l s u r p l u s in th is s tu d y . H ow ever, t o m e a s u re th e s e v a l u e s , t h e demand an d s u p p ly e q u a t i o n s m u st be s o lv e d f i r s t , by t a k i n g them s im u l t a n e o u s l y . e q u a tio n s ( 6 .1 ) and ( 6 .6 ) by s u b s t i t u t i n g S o lv in g t h e m ean v a l u e s f o r t h e in d e p e n d e n t v a r i a b l e s , t h e f o l l o w i n g e q u a t i o n s a r e o b t a i n e d : Demand: QW = 9103384 - 4699468 PWD ( 6 .5 3 ) S u p p ly : QW = 1979994 + 398017 PWD ( 6 .5 4 ) By s o l v i n g e q u a tio n s ( 6 .5 3 ) and ( 6 .5 4 ) s i m u l t a n e o u s l y , two e q u a t i o n s w ith two unknow ns, th e e q u i l i b r i u m q u a n t i t y and p r i c e a s 2 ,5 0 0 ,0 0 0 p o u n d s o f w h i t e f i s h o f $ 1 .4 0 p e r p o u n d . By p l o t t i n g e q u a t i o n s ( 6 .5 1 ) and 6 .5 2 ) i n t o t h e g r a p h i n F i g u r e V I - 1 , th e s o c i a l s u r p l u s c a n t h e n b e m e a su re d . a t a p ric e can be e s tim a te d P r ic e ($ ) Demand : (JV = 9 ,1 0 3 ,3 8 4 - 46 9 ,9 6 8 PWD . S u p p ly : CW = 1 ,9 7 9 ,9 9 4 + 398,017 PWD S u p p ly 2.0 1 .9 4 1 .5 P* 155 1.0 0 .5 1 .5 F ig u r e V I - 1 . 3 .0 4 .5 6.0 7 .5 E s tim a te d Demand a n d S u p p ly C u rv e s , S o c i a l S u r p lu s o f W h ite f is h fro m M ich ig an G r e a t W a te rs 90 QUANTITY ( m i lli o n pounds) 156 Consumer S u r p lu s ( a r e a ABP*) P r o d u c e r S u r p lu s ( a r e a 0P*BC) = $ 3 ,1 5 0 ,0 0 0 S o c i a l S u r p lu s (N e t a l l - o r - =$ 6 7 5 ,0 0 0 =$ 3 ,8 2 5 ,0 0 0 none v a l u e ) The s o c i a l s u r p l u s o b ta in e d fro m t h i s e s t i m a t e w as t h e s u r p l u s g a in e d o n th e a v e r a g e , a n n u a l l y , d u r i n g t h e 1 9 6 0 - 1 9 8 2 p e r i o d b a s e d .on t h e 1982 p ric e o f w h ite fis h . Chubs F o l l o w i n g t h e same p r o c e d u r e , t h e s o c i a l s u r p l u s fro m ch u b s c a n b e e s tim a te d . S u b s t i t u t i n g t h e mean v a l u e s i n t o e q u a t i o n s ( 6 . 2 ) a n d ( 6 . 7 ) r e s u l t s i n e q u a tio n s : Demand: QCH = 4795063 - 2372964 PCHD ( 6 .5 5 ) S u p p ly : QCH = 3049211 + 1081973 PCHD ( 6 .5 6 ) S o lv in g th e s e e q u a tio n s s i m u l t a n e o u s l y w i l l g iv e 3 ,6 0 0 ,0 0 0 p o u n d s o f c h u b s a t a p r i c e o f $ 0 .5 0 p e r pound a t t h e e q u i l i b r i u m . P lo ttin g r e s u l t s o f e q u a t i o n s ( 6 .5 5 ) an d ( 6 .5 6 ) g i v e s F ig u r e V I - 2 . E s tim a te s : Consum er s u r p l u s = $ 2 ,7 0 0 ,0 0 0 P ro d u c e r s u r p l u s = $ 1 ,6 6 2 ,5 0 0 v a lu e ) = $ 4 ,3 6 2 ,5 0 0 S o c i a l S u r p lu s (N e t a l l - o r - n o n e th e P r ic e ($) Demand : QCH = 4 ,7 9 5 ,0 6 3 - 2 ,3 7 2 ,9 6 4 PCHD S u p p ly : QCH = 3 ,0 4 9 ,2 1 1 - 1 ,0 8 1 ,9 7 3 PCHD 2.0 1 .5 Demand 1.0 157 P* 1.0 2.0 3 .0 5*° QUANTITY ( m illio n pounds) F ig u r e V I-2 . E s tim a te d Demand a n d Suppy C u rv e s , S o c i a l S u rp lu s o f Chubs f r a n M ich ig an G r e a t L ak es W aters 158 The a v e r a g e annual s o c ia l s u r p l u s g a i n e d f r o m c h u b s d u r in g t h e p e r io d 1 9 6 0 -1 9 8 2 w as $ 4 ,3 6 2 ,5 0 0 . farsh S u b s titu tin g t h e m ean v a l u e s f r o m t h e i n d e p e n d e n t v a r i a b l e s i n e q u a t i o n s ( 6 . 3 ) an d ( 6 . 8 ) w ould g i v e t h e e q u a t i o n s : Demand: QP = 1740636 - 1202093 PPD ( 6 .5 7 ) S u p p ly : QP = 795065 + 671583 PPD ( 6 .5 8 ) By s o l v i n g e q u a t i o n s q u a n tity o f 1,130,000 T hen p l o t t i n g (6.57) and (6.58) pounds a t a p ric e e q u a tio n s (6.57) an d s i m u l ta n e o u s l y t h e e q u i l i b r i u m of (6.58) $0.50 w o u ld b e o b t a i n e d . w o u ld r e s u l t i n F i g u r e VI-3. The e s t i m a t e o f s o c i a l s u r p l u s fro m p e r c h w a s: Consum er s u r p l u s =$ 5 3 6 ,7 5 0 P ro d u c e r s u r p lu s s $ 4 8 2 ,5 0 0 S o c i a l s u r p l u s (N e t a l l - o r - n o n e v a l u e ) = $ 1 ,0 1 9 ,2 5 0 T h is s o c i a l s u r p l u s w a s a l s o g a i n e d a n n u a l l y fro m p e r c h d u r in g th e 1960-1982 p e r i o d . % A3Leitils, S u b s t i t u t i n g e q u a t i o n s ( 6 .5 ) an d ( 6 .1 0 ) w ith t h e mean v a l u e s o f t h e in d e p e n d e n t v a r i a b l e s , r e s u l t s i n : P r ic e ($) Demand : QP = 1 ,7 4 0 ,6 3 6 - 1 ,2 0 2 ,0 9 3 S u p p ly : QP = 7 9 ,5 6 0 - 6 71,583 PPD PPD 1 .4 5 1.0 159 P* 0 .5 Demand 0 .5 F ig u r e V I-3 . 0.8 1 .0 1 .1 3 1 .5 2.0 E s tim a te d Demand a n d S u p p ly C u rv e s , S o c i a l S u r p lu s o f P e rc h fro m M ich ig an G r e a t L ak es W a te rs QUANTITY ( m i lli o n pounds) 160 Demand: S u p p ly : QAL = 5420650 - 36043716 PALD PALD = 0 .0 2 9 0 7 + 0 .4 6 9 x 10“ 8 QAL S o lv in g e q u a t i o n s ( 6 . 5 9 ) e q u ilib riu m (6.59) p ric e and o f $ 0 ,0 4 6 ( 6 .6 0 ) ( 6 .6 0 ) s i m u l t a n e o u s l y w o u ld p r o v i d e a n a t a q u a n t i t y o f 3 ,7 4 0 ,6 8 4 p o u n d s . T h ese e q u a tio n s a r e p lo t te d in F ig u re V I-4 . The s o c i a l s u r p l u s g a in e d fro m a l e w i f e w a s: C onsum er s u r p l u s = $ 1 9 2 ,4 0 0 P ro d u c e r s u r p lu s = $ 3 1 ,4 5 0 S o c i a l s u r p l u s (N e t a l l - o r - n o n e v a l u e ) = $ 2 2 3 ,8 5 0 A le w ife c o n t r i b u t e d a b o u t $ 2 2 3 ,8 5 0 a n n u a l ly i n te r m s o f s o c i a l s u r p l u s . The s o c i a l s u r p l u s fro m c a t f i s h w a s n o t e s t i m a t e d s in c e a s a tis fa c to ry s u p p ly f u n c ti o n th is c o u ld n o t be o b ta in e d . e s t i m a t e u s i n g e q u a t i o n ( 6 . 9 ) w as ex am in ed ( a l t h o u g h i t s l o p e ) , b u t no e q u i l i b r i u m w as o b t a i n e d . in s tu d y The h a s a n e g a tiv e The s u p p ly c u rv e fro m e q u a t i o n ( 6 . 9 ) n e v e r i n t e r c e p t e d t h e demand c u rv e o f e q u a t i o n ( 6 . 4 ) . S in c e th e e s ti m a t e d * s u p p l y c u r v e s o f w h i t e f i s h , c h u b s , and p e rc h i n t e r s e c t e d th e h o r i z o n t a l a x i s a t p o s i t i v e p ro d u c e r s u rp lu s m ig h t h a v e b e e n h i g h . q u a n tity , A d j u s t m e n t s w e r e m ade by a s s u m in g s u p p ly c u r v e s b e g a n a t t h e p o i n t o f o r i g i n . re a lis tic th e e s tim a te d T h e re fo re , p ro d u c e r s u r p lu s e s ti m a t e s w e re o b ta in e d . m o re The a d j u s t e d p ro d u cer s u r p lu s e s t i m a t e s w e re $ 1 ,7 5 0 , $950 and $280 th o u s a n d s f o r w h i t e f i s h , ch u b s and p e r c h , r e s p e c t i v e l y . The demand an d s u p p ly o f c o m m e r c ia l f i s h e r i e s m i g h t c h a n g e o v e r tim e . Any s h i f t i n g i n t h e demand and s u p p ly f u n c t i o n s w i l l a f f e c t th e 36,043,716 PALD 0.02907 + 0.469 x 10~8 4.6 Figure VI-4 . * 3 3 ,7 4 5 # Estim ated Demand and Supply Curves, S ocial Surplus o f A lew ife from M ichigan Great T-aW** 5.4 162 m a g n itu d e o f s o c i a l s u r p l u s e s . th e I f th e c h a n g e s c a u s e d a n e x p a n s io n i n s o c i a l s u r p lu s , th e w e lfa re o f s o c ie ty w i l l in c re a s e . On t h e o t h e r h a n d , an y c o n t r a c t i o n i n th e s o c i a l s u r p l u s w i l l r e d u c e t h e w e l f a r e o f s o o i e t y a s t h e w h o le . CHAPTER VII SUMMARY, CONCLUSION AND RECOMMENDATIONS SmnnarY As t h e w o r l d p o p u l a t i o n h a s g r o w n , w o r ld dem and f o r f i s h n u t r i t i o n so u rce h a s a ls o in c re a s e d s u b s t a n t i a l l y . p u t m ore p r e s s u r e on m a r in e f i s h s t o c k s . l a s t decade h a s l e v e l e d 1 9 7 0 's , w o r ld f i s h T h is , in e f f e c t , h a s W orld f i s h p r o d u c t i o n o v e r th e o f f w h ile f i s h i n g p ro d u c tio n in c re a s e d d e c l i n e fro m 6 p e r c e n t i n t h e 1 9 6 0 's . as a e f f o r t in c re a s e d . by l e s s I n th e t h a n one p e r c e n t , a The b a s i c c a u s e o f t h i s d e c lin e a p p e a r s t o b e t h e d e c r e a s e o f c o n v e n t i o n a l f i s h s p e c i e s w hose s to c k s m ig h t h a v e c o l l a p s e d , p r o v i d i n g m uch l o w e r y i e l d s . A s id e fro m th a t, a b o u t 3 5 p e r c e n t o f t h e f i s h c a u g h t , w h ich i s e q u i v a l e n t t o 25 m i l l i o n t o n s , a r e l o s t a n n u a l ly d u r i n g p r o c e s s i n g i n d e v e l o p i n g c o u n t r i e s . An a t t e m p t t o I n c r e a s e f i s h p r o d u c t i o n i n t h e f u t u r e , o t h e r th a n r e d u c i n g p o s t - h a r v e s t l o s s e s , w i l l d ep en d u p o n e f f o r t s t o e x p l o i t u n c o n v e n t i o n a l fis h s p e c ie s . The r o l e o f a q u a c u ltu re , a s w e ll a s f r e s h w a te r f i s h p r o d u c t i o n , c a n b e e x p e c te d t o grow i n t h e f u t u r e , w h ich m ig h t e a s e t h e p r e s s u r e on m a rin e f i s h s t o c k s . The G r e a t L ak e s a r e one o f t h e l a r g e s t f r e s h w a te r r e s o u r c e s i n th e w o rld . A lm o s t 4 0 p e r c e n t M i c h i g a n 's ju ris d ic tio n . im p o rta n t r e s o u r c e in h a lf of th e ir a re a is lo c a te d w ith in M i c h i g a n 's G r e a t L a k e s c o u l d b eco m e a n p ro d u c in g fre s h w a te r fis h if th e re is a w i l l i n g n e s s t o assum e t h i s r o l e t o g e t h e r w ith p r o p e r m anagem ent and t h e s u p p o r t fro m s t a t e an d o t h e r f i s h e r y c o n c e r n s . 163 O ver t h e l a s t h u n d re d 164 y e a r s , M ic h i g a n 's w a t e r s h a v e b e e n v e r y s t a b l e i n p r o d u c i n g f r e s h w a t e r fis h . A nnual t o t a l c a tc h pounds o v e r t h i s p e rio d . L akes i s f r o m M ic h ig a n w a t e r s w as c l o s e t o 30 m i l l i o n H ow ever, t h e u n iq u e c a s e i n M i c h i g a n 's G r e a t t h a t w h i l e p r o v id i n g a s t a b l e y i e l d , f i s h s p e c i e s c o m p o s itio n h a s changed c o n tin u o u s ly . d ra s tic a lly . T h e a b u n d a n c e o f m any s p e c i e s h a s c h a n g e d Some s p e c i e s w h ic h w e re a b u n d a n t i n t h e p a s t c o l l a p s e d , an d new , l e s s p o p u la r o r s m a l l e r f i s h s p e c i e s h a v e i n c r e a s e d t h e i r l e v e l o f abundance. O v e r f i s h i n g w a s c o n s i d e r e d among t h e m o st s i g n i f i c a n t f a c t o r s a f f e c t i n g th e s u c c e s s io n o f s e v e r a l s p e c ie s i n th e G r e a t L a k e s . The in v a s io n of sea la m p re y in to th e G re a t L ak es d e t e r i o r a t i o n o f th e G re a t L akes f i s h i n g s i t u a t i o n . caused m o re M ost o f t h e prem ium s p e c i e s p o p u l a t i o n s , s u c h a s l a k e t r o u t an d w h i t e f i s h , c o l l a p s e d o r w e re re d u c e d by th e p ro d u c tio n i n s e a la m p re y . in 1942 th e w h ite fis h t h e G r e a t L a k e s d ro p p e d t o 0 .1 m i l l i o n p o u n d s fro m o v e r 4 .1 m i l l i o n p o u n d s i n 1 9 3 1 . at As a r e s u l t , The l a k e t r o u t m o r t a l i t y r a t e w as e s t i m a t e d a b o u t 70 p e r c e n t a n n u a l l y . s m a lle r s p e c ie s a fte r th e C o m m e r c ia l f i s h i n g c o lla p s e of th e th e n p re m iu m s h ifte d s p e c ie s . to The e n v i r o n m e n t a l d e g r a d a t i o n o f t h e G r e a t L ak es h a s f u r t h e r a g g r a v a te d t h e p ro b le m s o f G r e a t L a k e s f i s h e r i e s . The d i s c h a r g e o f m i l l i n g w a s t e s fro m lu m b e rin g la k e s , in d u s trie s d e fo re s ta tio n in to th e o f d ra in a g e b a s in s , t h e c o n s t r u c t i o n o f d am s, p la n t n u tr ie n t w a s te s , c o n t a m i n a t i o n b y DDT, PCB, m e r c u r y a n d o t h e r p o i s o n s i n t o and th e t h e la k e % w a te r s in d i c a te d th e s e r io u s n e s s o f th e fis h e rie s . T h is s i t u a t i o n d i d n o t o n ly a f f e c t f i s h r e p r o d u c t i o n , b u t a l s o c a u s e d f i s h c o n t a m in a tio n . so h ig h , e s p e c ia lly p ro b le m s f a c e d by G r e a t L a k e s i n th e l a t e T he l e v e l s o f c o n t a m in a tio n w e r e f o u n d 1 9 6 0 's and 1 9 7 0 's , t h a t c o n s u m p tio n o f 165 th e f i s h p o s e d a d a n g e r f o r h u m an h e a l t h . M ic h i g a n r e s i d e n t s w e r e w arn ed n o t t o e a t G r e a t L a k e s f i s h m ore th a n o n ce a w eek . The c o m p e titio n w ith s p o r t f i s h i n g d e te rio ra tio n h a s f u r t h e r a g g ra v a te d th e o f M i c h i g a n 's co m m ercial f i s h e r i e s , s i n c e c u r r e n t p u b l i c p o l i c y i n M ic h ig a n t e n d s t o f a v o r s p o r t f i s h i n g . Many r e s t r i c t i o n s and r e g u l a t i o n s h a v e b e e n im p o se d o n c o m m ercial f i s h i n g by t h e s t a t e . T h is w as done n o t o n ly t o r e s t o r e f i s h p o p u l a t i o n s o r t o p r e v e n t o v e r f i s h i n g , but a ls o t o g i v e a m ore d o m in a n t r o l e t o s p o r t f i s h i n g i n t e r e s t s . s h if t in e m p h a s is i s c o m m e r c ia l f is h e r m e n . o f th e s p o r t f i s h L ic e n s e and gear re fle c te d in th e am ount o f f i s h T h is h a rv e s te d by C om m ercial f i s h c a t c h e s am ount t o o n ly o n e - t h i r d c a t c h e s o f som e s i x t y re s tric tio n s , m illio n b a n n in g of pounds g illn e ts , a n n u a lly . and zone r e s t r i c t i o n s f o r c o m m e rc ia l f i s h i n g a r e am ong m any o f t h e r e g u l a t i o n s im p o s e d b y t h e M i c h i g a n D e p a r tm e n t o f N a tu r a l R e s o u r c e s o n c o m m ercial fis h e rie s . fis h e ry P o lic y d e c i s i o n s r e g a r d i n g t h e m a n a g e m e n t o f c o m m e r c ia l r e s o u r c e s w o u ld r e q u i r e th e c o n s i d e r a t i o n o f eoonom io v a l u e s i n a d d itio n to b io lo g ic a l a s p e c ts . The e x c l u s i o n o f e co n o m ic v a l u e s i n t h e f o r m u l a t i o n o f p u b l i c p o l i c y may h am p er e f f o r t s t o a t t a i n e f f i c i e n c y i n th e u t i l i z a t i o n o f f i s h e r y r e s o u r c e s . T h e m a in o b j e c t i v e o f t h i s s tu d y was t o p r o v id e i n f o r m a t i o n o n th e eco n o m ic a s p e c t s o f co m m e rc ia l f i s h e r i e s . The e f f e c t o f v a r i o u s f a c t o r s o n f i s h p r o d u c t i o n o v e r tim e w e re e x p lo r e d an d d o c u m e n te d , and t h e l e v e l o f f i s h h a r v e s t e d a t m axim um s u s t a i n a b l e y i e l d (MSY) w a s e s t i m a t e d . Maximum e f f o r t d e v o te d t o f i s h h a r v e s t s a t MSY w as a l s o e s t i m a t e d . w h i t e f i s h , w h ere c o s t d a t a w as a v a i l a b l e , maximum e c o n o m ic y i e l d and e f f o r t a t MEY w e re a l s o e x a m in e d . For (MEY) To a n a l y z e w h ic h f a c t o r s a f f e c t e d M ic h ig a n f i s h p r i c e s , dem and a n d s u p p l y e q u a t i o n s w e r e e s t i m a t e d s e v e r a l M ic h ig a n f i s h c o m m o d it ie s . fo r T h ese m o d e ls w e re t h e n a p p l i e d t o a n a ly z e t h e r e s p o n s e s o f b u y e r s an d s e l l e r s t o p r i c e c h a n g e s , a s w e l l a s t h e p o t e n t i a l s o c i a l s u r p l u s g a in e d fro m c o m m ercial f i s h e r i e s . To a t t a i n t h i s o b j e c t i v e , th e s tu d y w as d iv i d e d i n t o tw o s e c t i o n s . F irs t, a b io e c o n o m ic m odel was d e v e lo p e d f o r t h e b i o l o g i c a l s i d e o f t h e a n a ly s is . L in e a riz a tio n b io e c o n o m ic p a r a m e te r s . W h ite fis h . y ie ld te c h n iq u e s w e re in tro d u c e d F o r th e p e rio d at 8 .5 1 9 6 0 -1 9 8 2 , maximum s u s t a i n a b l e m illio n pounds, eco n o m ic y i e l d w as a t 8 .4 m i l l i o n p o u n d s. 3 5 ,9 0 0 an d 3 3 ,1 0 0 a t MEY. y ie ld e d e s tim a te The r e s u l t s w e re : w as r e a c h e d m illio n , to a n d maximum E f f o r t a t MST w as P ro d u c e r s u r p l u s a t MSY w as $ 9 .1 8 a n d $ 9 . 2 m i l l i o n a t MEY. d if f e r e n t e s tim a te s . The 1 9 7 1 -1 9 8 2 d a ta Maximum s u s t a i n a b l e y i e l d w as 3 .2 3 m i l l i o n p o u n d s , an d 2 .7 7 m i l l i o n p o u n d s a t MEY. E ffo rt a t MSY w as 6 6 ,0 0 0 u n i t s , and e f f o r t a t MEY w as 4 1 ,0 0 0 u n i t s . P r o d u c e r s u r p l u s a t MSY w as $ 1 .0 8 m i l l i o n , and $ 1 .6 1 m i l l i o n a t MEY. P e rc h . M axim um s u s t a i n a b l e y i e l d w a s r e a c h e d a t '1 . 2 2 m i l l i o n p o u n d s w ith 2 1 ,5 0 0 u n i t s o f e f f o r t . C a tfis h . A bout on e m i l l i o n pounds o f c a tf is h h a r v e s t e d a t MSY w ith 1 4 ,7 0 0 u n i t s o f e f f o r t . m ig h t be 167 A le w if e . Maximum s u s t a i n a b l e y i e l d o c c u r r e d a t 5 .8 7 m i l l i o n pounds w ith 338 u n i t s o f e f f o r t . S e co n d , t h e dem and f o r a n d s u p p ly o f s e v e r a l f i s h s p e c i e s w e re e s t i m a t e d u s in g se v e ra l re g re s s io n te c h n iq u e s . s im u lta n e o u s e q u a t i o n m e th o d s w e re u s e d . From t h o s e r e s u l t s p ric e and The s i n g l e e q u a t i o n a n d 3SLS m e th o d s p r o v i d e d t h e m o s t s a t i s f a c t o r y e s tim a tio n s . B o th s i n g l e - e q u a t i o n r e s u l t s f o r demand an d s u p p ly e la s tic ity and f l e x i b i l i t y of d em an d a n d s u p p l y w e re th e n d e r iv e d an d su m m a riz e d , a s shown i n T a b le s V I-11 an d V I-1 2 . The e s tim a te d dem and an d s u p p ly e q u a tio n s w e re a l s o u s e d t o e s t i m a t e s o c i a l s u r p l u s ( n e t a l l - o r - n o n e v a l u e ) f o r s e v e r a l M ic h i g a n f is h s p e c ie s . T a b le V I I - 1 . T he r e s u l t s a r e su m m arized i n T a b le V I I - 1 . The E s t i m a t e s o f S o c i a l S u r p lu s ( n e t a l l - o r - n o n e v a l u e ) f o r S e v e r a l C om m ercial F i s h S p e c i e s i n M ich ig an ( i n th o u s a n d d o l l a r s ) Consum er S u r p lu s S p e c ie s (1 ) V h ite fis h P ro d u c e r S u r p lu s (2 ) P ro d u c e r S u r p lu s (a d ju s te d ) (3 ) S o c ia l S u r p lu s (4 )* (1 )+ (2 ) S o c ia l S u r p lu s (a d ju s te d ) (5 )= (1 )+ (3 ) 675 3 ,1 5 0 1 ,7 5 0 3 ,8 2 5 2 ,4 2 5 Chubs 2 ,7 0 0 1 ,6 6 2 950 4 ,3 6 3 3 ,6 5 0 P e rc h 536 482 280 1 ,0 1 9 817 A le w ife 192 31 — 224 — The s o c i a l s u r p l u s o f $ 4 ,3 6 2 ,5 0 0 y i e l d e d by c h u b s w as t h e h i g h e s t , f o l l o w e d by w h i t e f i s h w i t h a le w ife . $ 3 ,8 2 5 ,0 0 0 . T h e n f o l l o w e d by p e r c h and Conclusions and Recommendations B a s e d o n t h e f i n d i n g s o f t h i s s tu d y , c u r r e n t w h i t e f i s h p r o d u c ti o n seem s v e r y d o s e t o t h e maximum s u s t a i n a b l e y i e l d a n d maximum e c o n o m ic y ie ld (u s in g w h ite fis h 1 9 6 0 -1 9 8 2 d a t a ) . H o w e v e r, th e 1971-1982 d a t a show t h a t p r o d u c t i o n w a s b e y o n d t h e m aximum s u s t a i n a b l e y i e l d , w h ite fis h s to c k s w e re o v e r f is h e d . The c o n t i n u a t i o n o f f i s h i n g c u rre n t l e v e l s w i l l re d u c e th e s to c k s , s m a lle r. so th e f u tu r e and at c a tc h w i l l be E f f o r t a t p r e s e n t i s l a r g e r th a n t h e e s t i m a t e d e f f o r t a t b o th MSY and MEY. T h ese tw o e s t i m a t e s m ig h t i n d i c a t e t h a t t h e c u r r e n t l e v e l o f w h ite fis h p ro d u c tio n i s in t h e r a n g e o f maximum s u s t a i n a b l e y i e l d . P r e c a u t i o n a r y s t e p s m ig h t be u n d e r ta k e n t o p r e v e n t s u b s t a n t i a l i n c r e a s e s in t h e h a r v e s t o f w h i t e f i s h f o r two o r t h r e e y e a r s . n o t in T h is w o u ld e n s u r e th a t w h ite fis h s to o k s a re th e s ta g e o f c o lla p s e . An e v e n t e x p e rie n c e d in t h e d e p l e t i o n o f P e r u v i a n anch o v y s t o c k s i n t h e e a r l y 1 9 7 0 's ( P i t c h e r an d H a r t , 1982) re m in d e d m a n a g e rs t o b e m ore c a u t i o u s i n th e m anagem ent o f f is h e r y re s o u rc e . Two o r t h r e e y e a r s w i l l g iv e tim e t o o b s e r v e t h e c o n d i t i o n o f w h i t e f i s h s t o c k s an d a lm o s t en o u g h t i m e f o r w h i t e f i s h m a tu ra tio n . I n a d d i t i o n , r e g u l a r l y c o n d u c te d m e a su re m e n ts o f s i z e and w e ig h t o f w h i t e f i s h h a r v e s t e d a t random and w i l l f u n c t i o n a s a n e a rly w a rn in g t o th e c o n d itio n o f w h ite fis h s to c k s . The s u r p l u s y i e l d m o d e l, i n c o m b in a tio n w ith m o n ito r in g o f h a r v e s t s i z e a n d w e i g h t , p ro v id e u se fu l g u id e lin e s to f i s h e r y m a n a g e rs. can W h ile t h e r e a r e l i m i t a t i o n s i n th e s u r p l u s p r o d u c ti o n m o d e l, a s d i s c u s s e d i n C h a p te r I I , it c a n p ro v id e a "se c o n d b e s t" g u id e f o r p u b lic m a n a g in g f i s h e r y re so u rc e s. Im p ro v in g th e p o lic y d e c is io n s in e s tim a te s m ig h t be 169 a c c o m p lis h e d by u s i n g a m ore c o m p le te an d s o p h i s t i c a t e d m odel s u c h a s a d y n a m ic p o o l m o d e l. P re s e n tly , im p ro v in g c a t c h a n d e f f o r t d a t a . h o w e v e r , e m p h a sis s h o u ld be g iv e n t o T h is c o u ld ad v an c e th e u se o f th e s u r p l u s y i e l d m o d e l. The s p o r t f i s h e r y w as n o t i n c o r p o r a t e d i n t h i s s tu d y . I f sp o rt f i s h i n g w as t a k e n i n t o c o n s i d e r a t i o n , t h e p o i n t o f m aximum a n d o p tim u m le v e l o f re s o u rc e e x p l o i t a t i o n m ig h t h a v e b e e n d i f f e r e n t t h a n w h a t w as fo u n d i n t h i s s t u d y . G e n e ra lly , th e e s tim a te d d em an d a n d s u p p l y f o r s e v e r a l M ich ig a n c o m m ercial f i s h s p e c i e s y i e l d e d a r e l a t i v e l y h ig h p r ic e demand f o r w h i t e f i s h , c h u b s , p e r c h and c a t f i s h . w e re r e l a t i v e l y lo w . e la s tic ity of The s u p p ly e l a s t i c i t i e s T h i s s i t u a t i o n m ig h t i n d i c a t e th a t th e c o n su m ers ( b u y e r s ) , r a t h e r th a n t h e p r o d u c e r s ( f i s h e r m e n ) , w e re m ore r e s p o n s i v e t o p r ic e changes. d o c k s id e l e v e l , d is trib u to rs . S in c e t h i s s t u d y e x a m in e d t h e p r ic e a n a l y s i s a t th e th e b u y e rs an d p r i c e m a k e rs a r e th e w h o le s a le r s o r The f is h e r m e n , o n th e o t h e r h a n d , fu n c tio n as p ric e ta k e rs . By k n o w in g t h e m a g n itu d e o f e l a s t i c i t i e s (fro m demand an d s u p p ly ) p u b l i c p o l i c y m a k e rs m ig h t be a b l e t o f o r e s e e w h at w i l l b e t h e p r i c e and re v e n u e im p a c ts o f an y p o l i c y ch an g e w h ich a f f e c t s t h e f i s h a v a i l a b i l i t y f r o m M i c h i g a n 's G r e a t L a k e s . e la s tic ity W h ite fis h (b e tw e e n 2 .3 8 and 2 . 8 9 ) . fo r in s ta n o e , has a h ig h T h is i n d i c a t e s t h a t any o n e p e r c e n t in c re a s e in p r ic e w ill d e c re a se th e q u a n t ity o f w h ite fis h d e m a n d e d by m o re t h a n tw o p e r c e n t . The t o t a l re v e n u e r e c e i v e d by t h e f is h e r m e n i n th is as w e ll. case w ill c a tfis h d e c re a se A s im ila r s itu a tio n o c c u rs w ith d em an d , w h e re an y o n e p e r c e n t in c r e a s e in p r ic e w i l l d e c re a se t h e q u a n t i t y dem anded by a b o u t 1 .9 p e r c e n t . On t h e s u p p l y s id e , w ith 170 le s s e l a s t i c c o e f f ic ie n ts , e x c e p t f o r a le w ife , an I n c r e a s e one p e r c e n t w o u ld i n c r e a s e th e q u a n tity In p ric e o f s u p p lie d by l e s s th a n one p e rc e n t. The e s ti m a t e s o f s o c i a l q u ite h ig h . p o s itiv e The s u p p l y q u a n tity , s u r p l u s f o r w h i t e f i s h and ch u b s a p p e a r s o u rv e s in te r c e p te d th e h o r iz o n ta l a x is a t a i m p l y i n g t h a t a t z e r o p r i c e s t h e r e w e re s t i l l some q u a n titie s o f f is h o ffe re d . T h e s u p p l y o u rv e e s t i m a t e s d i d n o t seem v e r y c o n s i s t a n t . n e g a tiv e s lo p e s , and a l l p o s itiv e q u a n titie s . h ig h . A s im p le s u rp lu s e s tim a te s . th e h o r iz o n ta l a x is a t la rg e As a r e s u l t , th e p r o d u c e r s u r p l u s e s t i m a t e s seem ed T h e o ry s u g g e s ts G u rv a lin e a r. in te rs e c te d Some h ad th a t th e s e s u p p ly c u r v e s m ay a c t u a l l y be a d ju s tm e n t s i g n i f i c a n t l y re d u c e d th e p ro d u c e r T h e s e m o d e ls w e r e m o d i f i e d b y a s s u m in g t h a t t h e s u p p ly c u rv e w as a s t r a i g h t l i n e fro m t h e o r i g i n t o th e e q u i l i b r i u m p o i n t . V ith t h i s a d j u s t m e n t , t h e p r o d u c e r s u r p l u s o f w h i t e f i s h , chubs, and p e r c h ( a l s o a d j u s t e d ) w ould d ro p t o $ 1 .7 5 m i l l i o n ; $ 0 .9 m i l l i o n ; and $ 0 .2 8 m i l l i o n , r e s p e c t i v e l y . p e rc h (a ll at T o t a l r e v e n u e fro m w h i t e f i s h , m ean v a l u e s ) w e re $ 3 .7 ; and On a v e r a g e , a d ju s tm e n t) t o t a l r e v e n u e w e re 4 7 ? f o r w h i t e f i s h , 42? f o r c h u b s and 45? f o r p e r c h . o f p ro d u cer $ 0 .6 m i l l i o n , re s p e c tiv e ly . to th e r a t i o s $ 2 .2 ; c h u b s , and The s o c i a l s u r p l u s e s o f t h e s e f i s h s u rp lu s (a fte r c o m m o d itie s , e x c e p t w h i t e f i s h , w e re h i g h e r th a n t o t a l r e v e n u e . S u g g e s tio n s f o r F u r t h e r R e s e a rc h Few eco n o m ic s t u d i e s h a v e exam in ed M ic h i g a n 's c o m m ercial f i s h e r i e s . L ack o f i n f o r m a t i o n an d k n o w led g e o f s o c io - e c o n o m ic v a l u e s c o u l d h a m p e r e f f o r t s t o m anage f i s h e r y r e s o u r c e s e f f i c i e n t l y . Any r e s e a r c h w h ic h w o u ld a d d i n f o r m a t i o n an d a c c u m u la te m ore eco n o m ic v a l u e s w o u ld be v e r y h e l p f u l t o t h e p u b l i c p o l i c y d e c i s i o n m ak in g p r o c e s s . th is s tu d y i s C o n tin u a tio n o f o n e o f m any a v e n u e s f o r f u t u r e r e s e a r c h . E x p a n d in g t h e s tu d y o f dem and a n d s u p p l y , s u c h a s u s i n g a n o n - l i n e a r a p p r p a c h a n d o th e r m o d e l s w h i c h m i g h t b e m o re s u i t a b l e c o m m o d itie s , i s a p o s s i b i l i t y . f o r M ic h i g a n f i s h e r i e s A s tu d y o n t h e p o s s i b i l i t y o f b a c k w a rd s l o p e o f s u p p ly c u r v e s f o r M ic h ig a n c o m m ercial f i s h e r y i s a n a r e a w h ich c o u ld be e x p l o r e d . I f n o t l i m i t e d by t h e a v a i l a b i l i t y o f d a t a , r e s e a r c h o n demand an d s u p p ly a t t h e r e t a i l e r l e v e l w o u ld be a n i n t e r e s t i n g t o p i c to be s tu d ie d . d o c k s id e le v e l c o lle c tio n . o b ta in in g A s tu d y o f c a tc h m i g h t im p r o v e t h e C u rre n tly , th is and e f f o r t r e l a t i o n s h i p s s y ste m o f c a t c h r e p o r t s m ade b y f i s h e r m e n in fo rm a tio n . th e and e f f o r t d a t a s o le m e th o d fo r Im p ro v em en ts i n th e q u a l i t y o f c a t c h and e f f o r t d a t a may b e a g r e a t h e l p f o r . t h e f u t u r e f i s h e r i e s re se a rc h e r. at e c o n o m ic s BIBLIOGRAPHY BIBLIOGRAPHY A n d e rso n , L ee G. 1 9 7 7 . T h e E c o n o m io s o f F i s h e r i e s M a n a g e m e n t. Jo h n H o p k in s U n i v e r s i t y P r e s s , B a ltim o r e . The Brow n, E d w ard . 1968. " P o p u la tio n C h a r a c t e r is t i c s and P h y s ic a l C o n d itio n o f A le w iv e s , A lo s a P s e u d o h a re n g u s , i n A M a s s i v e D i e o f f in L ake M i c h i g a n , 1 9 6 7 . " G r e a t L a k e s F i s h e r y C o m m is s io n , T e c h n ic a l R e p o r t No. 13. Ann A rb o r. B u tlin , Joh n . 1975. " O p t i m a l D e p l e t i o n o f a R e p l e n is h a b le R e s o u rc e : An E v a l u a t i o n o f R e c e n t C o n t r i b u t i o n s t o F i s h e r i e s E c o n o m ic s ." T h e E c o n o m ic s o f Na t u r a l R e so u rc e D e p le t io n . Ed. D.W. P e a rc e and J . R o se. J o h n W ile y & S o n s , New Y ork. C a to , Jam es C. F is h e r y ." 1976. " D o c k s i d e P r i c e A n a l y s i s i n t h e F l o r i d a M u lle t I n M arin e F i s h e r i e s R ev iew . V o l. 3 8 , No. 3 6 , J u n e . C h r i s t i e , W .J. 1974 " C h a n g e s i n t h e F i s h S p e c i e s C o m p o s itio n o f t h e G r e a t L a k e s . 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