A {*CPKLATIDM ST‘US‘? 0:: 1mg m" :35 VJEEQ'EERCREEN LM-ié. K11 mmmc CG U MTV}. ME CH 33- A24; $5932.;an WITH NOTES ON MG‘KEMEZQT AME Erma. {3'2" NEWIEQO C322 CCEQESE’E‘ECN Thai: for the Degree of M. S. MICHIGAN STATE. COLLEGE Carla: de la Mesa Fei‘ferolf, Jr. 1952 _ -r f .____ L..._1_ _.__ . x l 1 11-12515 1 ' ' I 1 l 11 1 ”WWW" L 2143021269 1 . 131293 10261 4913 . '. ' _ j W ' U ‘ \ . , 1 Pi ‘ \ " if! '3 ‘1_._.__ L s _. , A A .2 L '__._‘ _ I l L. . This is to certify that the y. l ‘. thesis entitled : f, “A population study of the fishes of r ". Wintergreen Lake, Kalamazoo County, Michigan: With notes f on movement and effect of . ‘ ‘ trap nettingon onfgnditionfl I . fl .5 presente I Carlos ‘l‘etterolf 1 'i l. c has been accepted towards fulfillment . , of the requirements for .01. " _ “.5. degree mm 1 1 1 . , .‘ 1 _ ' , Major professor . 1' : _.; 1 . . J .‘Q’q. 11} _’: Date March 11, 1952, 'j 0-169 '1 .1 '1 74 1 i _l -~i A POPULATION STUDY OF THE FISHES OF WINTERCREEN LAKE, KALAMAZOO COUNTY, MICHIGAN: WITH NOTES ON MOVEMENT AND EFFECT OF NETTING ON CONDITION By CARLOS de la MESA F'E'I'I‘thOIF, JR. W A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Zoology 1952 1* I'll lilfi.‘ All] I'll!!! k. \ v ”\ \\‘ II III IV VI VII --._ '\ V‘ TABLE OF CONTENTS LIST OF TABLES . . . . . . . LIST OF FIGURES . . . . . . ACKNOWLEDGEIENTS . . . . . . INTRODUCTION . . . . . . . HISTORY OF 'i‘i'II‘lTERCREEN TAKE DESCRIPTION OF WINTERGREEN TAKE . . . . Physical . . . . . . . Bottom Type . . . . . . Aquatic Vegetation . . Natural Fertilization . Plankton and Algae . . Limnology . . . . . . . Fish Fauna . . . . . . MARKING PROCEDURE . . . . METHODS OF CAPTURING FISH . Angling o o o o o o o o Netting........ COMPARISON OF FISH CAUGHT BY ANGLING-AND BY TRAP NETTING . . . MOVEi‘uENT OF FISH . . . . . . Review of Previous Investigations . Wintergreen Lake Results Explanation of Mbvement Diagrams Largemouth Bass . Common Bluegills . . . . . . . . Yellow Bullheads . Miscellaneous . . Comparison of Movements of Fish in Sugarloaf, Fife, and'Wintergreen Lakes ") “N a ... he I ~fg);~_1 ii Page iv vi viii CDCIDNNILT' E" ll 19 19 20 28 33 33 hi hi h3 58 61 so 71 iii TABLE OF CONTENTS (Continued) Page VIII ESTIMATED FISH POPULATIONS . . . . . . . . . . . . . . . 8h Method of Estimation . . . . . . . . . . . . . . . 81; Sampling Error of Population Estimates . . . . . . . 89 Use of Formulae . . . . . . . . . . . . . . . . . . 91 IX POPULATION ESTIHATES, STANDING CROP, AND ANNUAL YIELD OF WINTERGREEN LAKE . . . . . . 95 common Bluegill . O O C O O C O O . . O O O O C O O 97 Comon sunfj-Sh C O . O O O O C O O O O . . . O C . . 98 largemoutrl Bass . . C O C O C O C O O O O O C O O . 99 Ye 110W PerCh . 0 O . C O I C O O O O C O O C O C . 102 Common Sunfish X Common Bluegill Hybrid . . . . . . 105 Yellow Bullhead . . . . . . . . . . . . . . . . . . 106 80me O O . O O O O O C O O O O C O O O O O O O . 107 X IENCTH-FREQUENCY DISTRIBUTIONS . . . . . . . . . . . . . 108 XI COMPARISON OF THE STANDING CROP AND ANNUAL YIELD OF WINTERGREEN LAKE WITH OTHER ’KES . . ll? XII SULEEARoY . O . O O O O C O O C O O O C O O O . O O O O 0 1-21 XIII LI TERATUPLE CITED 0 O O O O C O I O O O O O O O O O O O 0 12h II III IV VI VII VIII XI XII XIII LIST OF TABLES ’Weekly Chemistry of Wintergreen Lake, April 6 - May 28, I951 . A Diurnal Chemistry of Wintergreen Lake N—e t-ting Record 0 O O O O I O O O O I O O I I O O O C Total Mortality and Yield for Spring and Summer, 1951, Wintergreen Lake . . . . . . . . . . . . . . . Comparison of K Factor of Fish Caught by Angling and by Netting . . . . . . . . . . . . . . . . . . . Summary of Movement of Tagged Bluegills in Third Sister Lake (Ball, l9hb) . . . . . . . . . . . . . . Summary of Revements of Bullheads in Third Sister lake (Ball, 19% ) O O O O O O O O O O O O O O O O 0 Analysis of Recaptures of marked Fish in Sugarloaf Lake (Cooper, 1951) . . . . . . . . . . . . . . . . Chi2 Test of Redistribution of Marked Fish in Sugarloaf Lake Chi2 Test for Independent Redistribution of Regional Markings on Largemouth Bass Caught by Angling, April August, 1951 Chi2 Contingency Test for Independent Redistribution of Marked Fish. Common Bluegills Caught by Angling and Netting, April - August, 1951, Wintergreen Lake Analysis of Recaptures of Fish Released at the Central Station in Sugarloaf and Wintergreen Lakes According to Whether Recovery was in the Same (S) or Opposite (0) Half as where Originally Marked . . . . . . . . Chi2 Homogeneity Test of Redistribution of marked Fish from Sugarloaf and Wintergreen Lakes . . . . . Comparison of Redistribution of Fish in Sugarloaf, Fife, and Wintergreen Lakes by Chi2 Homogeneity Test iv Page 11 23 26 31 33 3h 38 ho h8 61 78 79 8O XV XVII XVIII XIX XXI XXII XXIII XXIV XXVI LIST OF TABLES (Continued) Analysis of Recaptures of Fish Released in Home Half of Fife and Wintergreen Lakes According to Whether Recovery was in Same (S) or Opposite (0) Half as where Originally Marked . . . . . . . . . . . . . . . . . . Chi2 Contingency Test of Random Redistribution of Fish Released at a Central Station in Sugarloaf and Wintergreen Lakes . . . . . . . . . . . . . . . . Chi2 Contingency Test of Random Redistribution of Fish Released in their Home Half of Fife and Wintergreen Lakes . . . . . . . . . . . . . . . . . . TWO methods of Estimating Fish Populations. Hypo- thetical Examples are Used with the Assumption of no Mortality . . . . . . . . . . . . . . . . . . . . . Population Estimates of "Desirable Size" Fish in 'Wintergreen Lake. Confidence Limits of the Schnabel Method at the 95 Percent Level. Limits of One Stan- dard Error on the Schumacher and Eschmeyer Method . . Standing Crop of "Desirable Size" Fish ianintergreen Lake, Based on Population Estimates from Table XIX . . Tbtal Length—Frequency Distribution of Yellow Perch from Wintergreen Lake. All Fish Captured by Angling . Total Length-Frequency Distribution of Common Blue- gills fromeintergreen Lake. ‘All Fish Captured by Angling O O O O O O O O O O O O O O O O O O O O O O C Total Length—Frequency Distribution of Common Sunfish from Wintergreen Lake. All Fish Captured by Angling . Total Length—Frequency Distributions of Yellow Bull- heads Captured by Netting and Common Sunfish X Com- mon Bluegill Hybrids Captured by Angling in Winter- green Lake, May - August, 1951 . . . . . . . . . . . Total Length—Frequency Distribution of Bowfins Cap- tured by Angling, Spearing, and Trap Netting from Wintergreen Lake, April - August, 1951 . . . . . . . . Standard Length—Frequency Distributions of Largemouth Bass, Yellow Perch, Common Bluegill, Common Sunfish, and the Common Sunfish X Common Bluegill Hybrid from Winter- green Lake, April - September, 1951. All Fish Captured by Angling and Trap Netting . . . . . . . . . . . . . . Page 81 e 83 93 95 96 111 112 111; 115 1L5 3a 3b ha bb 5a Sb 9a LIST OF FIGURES Map of Wintergreen Lake, Kellogg Bird Sanctuary, Hickory Corners, Michigan . . . . . . . . . . . . . . . Great Lakes Trap Net . . . . . . . . . . . . . . . Actual Numbers Indicating where Regional Marks were Reobserved. Largemouth Bass Originally Caught by Angling, Wintergreen Lake, April - August, 1951 . . . . Percentages Indicating where Regional Marks were Reobserved. Largemouth Bass Originally Caught by Angling, Wintergreen Lake, April - August, 1951 . . . . Actual Numbers Indicating where Regional Marks were Reobserved. Largemouth Bass Originally Captured by Angling, Wintergreen Lake, April and May, 1951 . . . . Percentages Indicating where Regional Marks were Reobserved. Largemouth Bass Originally Captured by Angling, Wintergreen Lake, April and Hay, 1951 . . . Actual Numbers Indicating where Regional Marks were Reobserved. Largemouth Bass Originally Captured by Angling, Wintergreen Lake, June, July and August, 1951 Percentages Indicating where Regional marks were Reobserved. Largemouth Bass Originally Captured by Angling, Wintergreen Lake, June, July, and August, 1951 Actual Numbers Indicating where Regional marks were Reobserved. Largemouth Bass Originally Captured by Netting, Wintergreen Lake, Hay — August, 1951 . . . . Actual Numbers Indicating where Regional Marks were Reobserved. Common Bluegills Originally Captured by Netting, Wintergreen Lake, April - August, 1951 . . . . Actual Numbers Indicating where Regional marks were Reobserved. Common Bluegills Originally Captured by Angling, Wintergreen Lake, April - August, 1951 . . . . Actual Numbers Indicating where Regional Marks were Reobserved. Yellow Bullheads Originally Captured by Netting,'flintergreen Lake, April — August, 1951 . . . . vi Page 22 AS ’47 50 5h 56 60 63 65 9b 10 11 vii LIST OF FIGURES (Continued) Page Percentages Indicating where Regional Marks were Reobserved. Yellow Bullheads Originally Captured by Netting, Wintergreen Lake, April - August, 1951 . . . . . . 70 Actual Numbers Indicating where Regional Marks were Reobserved. Common Sunfish, Wintergreen Lake, May - August, 1951 . . . . . . . . . . . . . . . . . . . . 73 Actual Numbers Indicating where Regional Marks were Reobserved. Common Sunfish X Common Bluegill Hybrid, Plintergreen 1.31:8, Ziay " 1111511513, 1951 o o o o o o o o o o 0 7S viii ACKNOW LED "WEE-“EN TS The author is grateful to Dr. Peter I. Tack for his ~idance and en- thusiasm throughout this study. Much of the statistical analysis was suggested and supervised by Dr. Don W. Hayne, who gave generously of his time and energy. Iowever, the author accepts full responsibility for any errors of calculation or in method of application. Appreciation is ex- tended to Dr. Robert C. Ball for the use of his extensive library. The cooperation and assistance of Dr. Arthur E. Staebler, director of the Kellogg Bird Sanctuary, in the field work was invaluable. Dr. Gerald W. Prescott supervised the laboratory analysis of plankton and the identi— fication of higher aquatic plants. I am also indebted to him and Dr. Ball for their critical reading of this manuscript. The Michigan Insti- tute for Fisheries Research and the Fish Division of the Michigan Con- servation Department supplied ready access to their unpublished reports on'Wintergreen Lake. Thanks are due Dr. Gerald P. Cooper for permission to use material from one of his papers which is in press. ‘The summer field work with the large trap nets could not have been accomplished without the assistance of the following: Ralph Morrill, Dean Williams, Raymond Sharpe, Winifred Ford, Richard Hansen, David Stafford, Alfred Brower, and Aelred Geis. Allan Hirsch aided the author in the spring plankton observations and with the capture and release of the first 800 fish. His cooperation, as well as that of other student colleagues, is sincerely appreciated. Acknowledgement is due Miss Norma Lorraine Baughan who assisted in the laboratory and field tabulation of data and with some of the typing of the manuscript. A POPULATION STUDY OF THE FISHES OF WINTERGREEN LAKE, KALAMAZOO COUNTY, MICHIGAN: 'WITH NOTES ON MOVEMENT AND EFFECT OF NETTING ON CONDITION CARLOS de la MESA FETTEROLE, JR. AN ABSTRACT Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Zoology Year 1952 Approved { :éfik pfi% ”8 Carlos M. Fetterolf, Jr. ABSTRACT A POPULATION STUDY OF THE FISHES OF WINTERGREEN LAKE, KALAMAZOO COUNTY, MICHIGAN: 'WITH NOTES ON MOVEMENT AND EFFECT OF NETTING ON CONDITION A forty-acre, shallow, warm water lake, heavily fertilized by water— fowl droppings, has a standing crop of approximately 265 pounds per acre of common bluegills, largemouth bass, common sunfish, yellow perch, com— mon bluegill X common sunfish hybrids, yellow bullheads, and bowfin. Only fish which an angler would consider of "desirable size" are included in this productivity figure. When yellow bullheads and bowfin are excluded from the total, the lake has a heavier standing crop per acre of game and pan fish than any natural lake listed by Rounsefell (19h6) or Carlander (1950). Fishing has been restricted for over 20 years and the exploita- tion rate is low, approximately 5.h percent by angling in 1952. Fish were captured by angling and trap netting. Mortality of fish in the nets prompted a comparison of the condition factor of fish removed from the nets with fish captured by angling. A't test showed that the fish removed from the trap nets had a significantly lower K factor than fish captured by angling. Populations were estimated by the mark and recapture method, using the formulae of Schnabel (1938) and Schumacher and Eschmeyer (l9h3). Confidence limits were applied to the former method and limits of one standard error to the latter. A discussion of the sources of error is included. The lake was divided into quarters by imaginary lines and all fish Carlos M. Fetterolf, Jr. captured in each quarter received a distinctive mark by removal of the appropriate fin. Fish captured by angling were released in their home quarter, while those captured by netting were released at a central re- lease point at the intersection of the dividing lines. TWO hundred and fifty-eight regional markings on largemouth bass originally captured by angling were reobserved. Of these, 110 (h2.6 percent) were reobserved in the quarter of their original capture. Twenty-two regional markings on common bluegills originally captured by netting were reobserved. Seven (31.8 percent) of these had returned to the quarter of their original marking. Forty-five regional markings on yellow bullheads originally captured by netting were reobserved. Thirteen (28.9 percent) of these had returned to the region of their original capture. Recaptures of other species were insufficient to yield satisfactory movement patterns. A statistical analysis of the movements of largemouth bass indicated that their redistribution from either the central release station or a regional release station was not random. Statistical tests suggested that largemouth bass exhibited a homing tendency. The hypothesis of random.redistribution of common bluegills and yellow bullheads from the central release station is statistically acceptable by the Chi2 test. Results from two similar investigations of fish movements (Cooper, 1951) were compared statistically with data fromeintergreen Lake. Analysis showed that the possibility of similar behavior patterns with respect to redistribution after release was likely. Length-frequency distributions showed that h9.8 percent of the WI 4 .C Cl. A ~u 1|; Carlos M. Fetterolf, Jr. largemouth bass were between 8.7 and 10.6 inches total length and 69.3 percent of the common bluegills were between 7.6 and 8.6 inches total length. The possibility that these fish exhibit rapid growth to these lengths and then undergo a sudden decrease of growth rate is discussed. INTRODUCTION Much of the present work in the widely expanding field of fresh- water fishery biology deals with population studies and interrelation- ships of predator and prey fishes. A lake is considered to be in "bal- ance" when it supports a large population of game and pan fish whiCh are growing at an average rate. Achievement of this "balanced" situation is one of the aims of fisheries management. In an effort to achieve a desirable "balance" between predator and prey members of a game and pan fish population, artificial fertilization of lakes and ponds has been carried out in many areas. ‘Wintergreen Lake, where this investigation was performed, appears to be an example of an unusual lake which produces fast-growing game and pan fish, which has a heavy standing crop of large sized fish, and over the last twenty'years has received large quantities of nutrients in the droppings of thousands of waterfowl. Since this lake, to a certain degree, represents the conditions which would be achieved by continued artificial fertilization, it offers opportunities to evaluate the results which might be accomplished by this type of management. Objectives of this study were to determine: (1) Total adult fish population. (2) Interrelationships of predator and prey species. (3) Mbvement and degree of territorialism of fish in the lake. (A) Effect of netting on condition factor of fish. (5) Composition of length-frequency distributions of fish. I N! I I uIII| 1' IIN I DI: If HISTORY OF WINTERGREEN LAKE The late Mr. W. K. KellOgg of the W. K. Kellogg Cereal Co., Battle Creek, Michigan, purchased the 500 acre farm that surrounds'Wintergreen Lake in 1926. His primary interest was to establish a sanctuary for waterfowl. In 1929 he turned the farm and sanctuary over to Michigan State College for agricultural experimentation and scientific investi- gations. The Ke110gg Company, in cooperation with the college, still operates a feed research unit on the farm. Before Mr. Kellogg purchased the lake, inhabitants of the vicinity exploited it more heavily than it has been in the past twenty years. The college has allowed ice fishing by permit for many years, but summer fishing has been very light in comparison with fishing pressure on simi- lar lakes of the region. local fishermen state that before the public access was denied, Wintergreen Lake had been a favorite fishing spot that always yielded fish of a larger average size than surrounding lakes did. A few of these people confided that gill nets had been used in the lake five or six nights each spring for a number of years before the sale to Mr. Kellogg. This practice continued, although on a reduced scale, after the lake had been turned over to the college. These poachers have not been active since the close of'World War II. The lake has been the object of several fisheries investigations during the past twenty years. Dr. John Greeley, now of the New York State Conservation Department, was the first investigator. He tagged bass with an opercle clip in 1931, but his tags pulled lose and the ex- periment was a failure. Dr. Miles D. Pirnie became director of the sanctuary in 1931 and cooperated with the Institute for Fisheries Re- search of the Michigan Conservation Department in investigations which resulted in six unpublished reports dealing with'Wintergreen Lake (Re— port numbers 280, 289, 365, 366, 366A, and 790). Information from these papers will be incorporated at appropriate points in this thesis. DESCRIPTION OF W NTERCfii—SEN IAKE Physical 'Wintergreen Lake (Tier 1 south, Range 9 west, Section 8) is located on the W. K. KellOgg Bird Sanctuary of Michigan State College in Ross Township, Kalamazoo County, Michigan. The lake has an area of 39.33 acres, according to measurements taken from a topographical survey of the sanctuary prepared by engineers of the landscape architectural firm of T. Glenn Phillips, Detroit, Michigan in 1937. Depth contour lines were added by F. Earl Lyman about 1935, while he was a graduate student at Michigan State College. Measurements of these contour lines show that the lake has a mean depth of 7.56 feet and a volume of 297.16 acre feet. Maximum depth is 6.5 meters or 21.33 feet. Drainage area is 530 acres. There are no permanent feeder streams. The two streams indicated in Figure l are in- termittent. At the south end of the adjoining swamp area there is an outlet which empties into Gull Lake, a half mile distant. Presumably, springs located on the north and northeast shore keep the lake at a fairly constant level. 'Wintergreen Lake lies in the Kalamazoo-Mississinawa moranic system outwash plain. This plain is characterized by numerous lakes in the morainic basins and in the pits in the outwash plain. (GeolOgic his— tory from I. D. Scott, 1920.) 'Wintergreen Lake is one of many small pit lakes in the vicinity. .czonm one meowpmvm cowpooHHoo copxcmad one «supmHEono .mcaepwc HH4 .mnopnmsw once mama one mnfloflpflo nomad one mzonm awe mega .cmmHSOflE .mpocnoo hhoxofim .mnmgaonmm onflm wwoaamm .mxmq moonwaopzflg. .H opsmflm . 'I I 393.. >1 0 1.0 45. E at... £5ng 2 rccozao. uu¢4l\’\ £2950- ca4an . 3935 2.5.1254, 5: .2: put too... O \ . nn On . (U¢( nausea 23:: a. 1:3 5.: 30:;qu new: . 32:23.3 03411.3. r 2239.2» o...- 0333 . 32.. zuuzocmpz; r. s a I ‘v“-------’ \-~‘ - ‘ Bottom Type Bottom deposits are variable. The south and west shore is pulpy peat to a depth of three feet, where marl becomes intermixed with it. marl is predominant to a depth of about twelve feet in all other parts of the lake except the east and northeast shore. These shores are ex- posed to wave and wind action and are sandy to a depth of 2.5 feet where marl again becomes predominant. Beyond the twelve-foot depth the bottom is of a fine organic ooze. Aquatic Vegetation Chara is dominant in the shallow areas of the lake. As the depth increases, two species of Potamogeton become abundant: Sago pondweed, Potamogeton pectinatus, and leafy pondweed, Potamogeton foliosus. Coon- tail, Ceratophyllum demersum, and bushy pondweed, Najas flexilis, com— bine with the potamogetons to give a dense weed bed extending to about the four meter contour. Beds of spatterdock, Nuphar advena, occur along the shore in the southwestern half of the lake. There are two patches in the northeastern half; one in the eastern corner and another in the northwestern corner. 'White'water lily, Nymphaea (Castalia of authors) odorata, is limited to the lagoon area at the southern tip. The shore- line vegetation consists predominately of two species: Swamp loose- strife or water willow, Decodon verticillatus var. laevigatus, and button bush, Cephalanthus occidentalis. Natural Fertilization Many recently published fisheries articles and much of the present fisheries research work deal with enrichment of lakes by addition of fertilizer. This lake is perhaps one of the richest in the country from the standpoint of the nutrients added by natural fertilization. Each fall from 6,000 to 10,000 Canadian geese use the sanctuary as a stopping over place on their southward migration. An equal number of ducks are also present at this time and a flock of about 70 swans, geese, and ducks use the lake the year around. The extent to which the tremendous amount of natural fertilizer in their droppings improves the environment for fish production is unknown. The luxuriant higher aquatic plant growth has been described above. The bottom fauna is rich in quantity and utilized by the pan fish as food (Funk, l9h2). 0n numerous occasions during calm days, black terns visit the lake and feed on emerging midges near the water surface. Plankton and Algae The plankton and other algal growths are very abundant and deserve mention. An algal study was made by taking algal collections on the lake one day a week from.Apri1 6 to May 28, 1951. Sampling was done with a Kemmerer water sampler at two stations. One station was permanent, in the deepest part of the lake, where six samples were taken weekly; two each at the surface, three meters, and five meters. Two surface samples were taken from the shore against which the waves broke. One of each pair of samples was settled with mercuric chloride whereas the 9 other was centrifuged. Resulting concentrates were treated as suggested by G. W. Martin, Iowa State College, in an unpublished manuscript. Num- bers of organisms were obtained by the following formula - Average num- ber of organisms per field x number of fields in area of cover slip x number of drops per cc. x 1000 all divided by concentration factor equals number of organisms per liter. This method was used for the microplank- ton. The macroplankton was counted by use of a low-power binocular microscope and the number obtained was discrete. Dr. Gerald W. Pres— cott, Michigan State College Botany Department, supervised the labora- tory analysis and served as an advisor to the investigators. At the peak of the spring bloom on.Apri1 6, 1951 the average num— ber of algal and protozoan organisms per liter of lake water was 70 mil- lion. The Secchi disk reading averaged 0.8 meters while water tempera- ture was h3 degrees F. with pH of 7.5 and methyl orange alkalinity of 176. One month later on May 6, the average number of organisms per liter had dropped to 350,000. The Secchi disk could be seen resting on the lake bottom in 6.5 meters of water. 'Water temperature was 62 de- grees F., pH 7.3, and methyl orange alkalinity averaged 162. On April 6 the samples were made up of Schroederia and chlotella in a two to one ratio, with Euglenoids, Synedra, Navicula, Chlamydomonas, and ciliated protozoans being incidental. On May 6 there was no one species that was dominant. The samples contained.Cyclotella, Schroederia, Euglenoids, ciliated protozoans, Chroococcus, Scenedesmus, Synedra, Asterionella, and Navicula in equal numbers. Unidentified green and blue green algal cells were present occasionally. 10 The population of macroplankton, Cladocera, Ostracods, Copepods, and Rotifera, varied from a low of 11 per liter on April 6 to a high of 97 per liter on May 6. On this latter date, while the water was excep- tionally clear, the Cladocerans were in layers so thick that they pre- sented the appearance of a false sandy bottom to the eye. They were not taken abundantly in the samples after that date through May 28 when sam- pling was discontinued. The filamentous algae showed a similar cycle. They were almost non-existent until May 6. They reached their peak of abundance in the following month. Their bloom was concurrent with the rapid growth of the potamogetons. ‘Conditions for both algae and larger vegetation must have been good coincidentally, for each newly developed higher plant would have a growth of algae on it. Many of these algae became plank- tonic as high winds stirred the water and broke many filaments loose from the bottom and from the potamogetons during the week of May 6 - 12. 'flggtgg balls were present on the lake bottom during the spring and summer. All of the above information on plankton and algae came from an unpublished report by Fetterolf and Hirsch (1951). The next observations on the lake were in the latter part of June at the onset of a dense Microgystis bloom which remained during the en- tire summer . Limnology Temperatures and some chemical information were recorded concur- rently'with the plankton study. A diurnal chemical analysis was taken on September h and 5, 1951. Results are presented in Tables I and II. TABLE I ll ‘WEEKLY CHEMISTRY OF WINTERGREEN LAKE, APRIL 6 — MAY 28, 1951 Station Temp. Depthl Date see map Time ‘Weather Air H20 meters pH MOA Secchi April 6 1 1210 .2 clouds 53 D3 Surf. 7.5 176 .8 m. SE wind h3 3 7.5 178 0-5 mph DB 5 7.5 178 2 1330 53 hb Surf. 7.5 175 April 13 l 1300 Sleet 36 h6 Surf. 7.h 168 .85 m. SW wind h6 3 7.h 175 20-25 mph h6 5 7.h 172 3 1500 to Surf. 7.h 176 April 21 1 1500 Lt. rain 55 h? Surf. 7.3 1ou 1.15 m. NE wind h? 3 7.3 1o; 20 mph tt 5 7.t 172 April 22 h 1000 Overcast 50 h7.5 Surf. 7.3 172 SW wind 15 mph . April 27 1 17h5 .1 clouds o3 so Surf. 7.h 166 t.2 m. ssw wind 52.5 3 7.h 171 0-10 mph 50.5 5 7.h 170 5 1815 58 Surf. 7.h 16h May 6 1 1200 .2 clouds 56 62 Surf. 7.3 159 6.5 m. N wind 58 3 7.3 16h on 10-15 mph h9 S 7.3 171 bottom 13hS o2 Surf. 7.3 15h May 12 l 1615 .2 clouds 67 59 Surf. 7.h 153 6.5 m. w wind 55 3 7.11 159 on 5-10 mph 53 S 7.h 158 bottom 7 17kg o2.5 Surf. 7.h 15h May 20 1 1100 .1 clouds 80 73.5 Surf. 7.h 120 h.6 m. SW wind 67 3 7.h 13h strong 0-10 mph 59 5 7.h 160 winds 8 1230 76 Surf. 7.h 118 prior 36 hrs. May 28 1 0900 Overcast St on Surf. 7.h 112 5.2 m. SE wind 6h 3 7.h 110 10 mph 60 5 7.h 120 9 1020 o2 Surf. 7.h 110 l The depth of the lake at station number 1 was 6.5 meters and 1 meter at stations number 2 - 9. TABLE II 12 A DIURNAL CHEMISTRY OF WINTERGREEN LAKE Station Temp. Depth1 02 002 Date see map Time ‘Weather Air H20 meters ppm ppm Sept. h 10 1300 Clear 81 7O Surf. 7.1 0 SE wind 72.5 1 0-5 mph 70 2 2.5 6.8 0 69‘ 3 , , l 1L00 Clear 80 73.57 Surf. 7.2 O S wind 72 l ' 0-5 mph 70 2 7.3 0 69.5 3 6.3 0 69 h 3.1 1 65 5 0.0 26 59 6 0.0 ,_ 68 10 1715 Clear 72 757 Surf. 7.6 0 NE wind 73 1 0-5 mph 70 2 2.5 7.9 0 69 3 l 1815 Clear 70 7h Surf. 7.8 0 NE wind 72 1 0-3 mph 70.5 2 8.1 0 70 3 ho7 0 69 h 2.7 1 65 5 0.0 9 59 6 0.0 88 10 2100 Clear 59 73 Surf. 7.6 0 E wind 72.5 1 0—3 mph 71 2 72.5 7.1 o 70.5 3 l 2215 Clear ‘59 72 Surf. 7.9 O No wind 71.5 1 70.5 2 7.5 O 69.5 3 6.u 0 68.5 h h.8 0 65.5 5 1.8 9 59.5 6 0.0 72 Sept. 5'* 10 0100 Clear 53 72 Surf. 7.7 0 No wind 72 l 70 2 2.5 7.5 0 70 3 l 0200 Clear 53 71 Surf. 7.9 0 No wind 71 1 70 2 7.3 0 69.5 3 6.3 0 69.5 h 0.7 10 6h.5 5 0.7 20 59.0 6 0.0 81 71 The depth of the lake at station number 1 was 6.h meters and 3 meters at station number 10. 13 On May 2h a trapnet was set in 15 feet of water and allowed to fish for 3 days. Upon raising the net, all fish were in excellent condition and the net yielded one of the largest catches of fish of the season. The next trapnet set was on July 2 in water 10 feet deep. The net was raised 2 days later and the entire catch was dead. Since the time of the previous set the lake had stratified thermally and chemically. It is believed that fish entered the trap when the'water at that depth con— tained enough oxygen to sustain life, at least for a brief time. After becoming trapped the fish may have died because the dissolved oxygen content was too low to sustain life over an extended period or because of lowered oxygen content during the night when photosynthesis ceased. Rate of decomposition of decaying matter would be increased by warmer temperatures, thus adding to decomposition products in the deeper water. To test the hypothesis that there was less dissolved oxygen pre— sent during darkness than during daylight at the same depth an immediate diurnal chemical analysis should have been made. The chemical reagents to perform these tests were lacking and they were not procured until August. The latter part of August was cool and the mortality rate of fish in the nets was lower than usual. It was desired to have a warm period to make chemical tests, as stratification, both thermal and chem- ical, would be more clearly defined. The writer was unable to make the chemical analysis until September h and 5, see Table II. At 0200, September 5, there were 6.3 parts per million of dissolved oxygen present at 3 meters (9.8 feet) and 0.7 parts per million of dis- solved oxygen present at h meters (13.1 feet). This latter amount was much less than the amount found at that depth earlier in the diurnal 1).; cycle. Apparently the assumption that the same layer of water contained less oxygen during the night than during the day was correct. 'Whether this condition existed in July is unknown. However, it is believed that this condition would have been accentuated during the warmer month of July. Birge's definition of a thermocline (l90h, as cited by Welsh, 1935) states that the upper limit of the thermocline begins where the tempera- ture drop is 1 degree 0. or more per meter. Table II shows that the thermocline begins at a depth of h meters. It is regretted that fur- ther temperature and chemical tests were not taken during warm periods, for a person swimming could easily detect temperature changes with his feet. It is possible that chemical stratification accompanied the thermocline to this high level, although there is no proof. This stra— tification could be the cause of the mortality of fish in the nets, *when they were forced to remain there for extended periods. 15 Fish Fauna A list of the fishes found in the lake in May 1935 appears in an unpublished report of the Michigan Conservation Department, Institute for Fisheries Research (Cooper, 1935b). All but two of the species pres— ent at that time were found in 1951. There have been three additions to the list compiled in 1935. All scientific and common names are from Hubbs and Lagler (19h9). SCIENTIFIC NAME COMMON NAME Amia calva Linnaeus. Bowfin or dogfish Erimyzon sucetta kennerlii (Girard). 'Western lake chubsucker Notropis heterodon (Cope): Blackchin shiner Netropis heterolepis heterolepis NOrthern blacknose shiner Eigenmann and Eigenmann. NotrOpis cornutus chrysocephalus Central common shinerl (Rafinesque): Notemigonus crysoleucas auratus ‘Western golden shiner (Rafinesque). Hyborhynchus notatus (Rafinesque). Bluntnose minnow Ameiurus natalis natalis (LeSueur). Northern.yellow bullhead Esox vermiculatus LeSueur. Mud pickerel2 Perca flavescens (Mitchill). Yellow perch Poecilichthys exilis (Girard). Iowa darter3 Micropterus salmoides (Lacepede). Largemouth bass Lepomis qyanellus Rafinesque. Green sunfish lepomis gibbosus (Linnaeus). Pumpkinseed or common sunfish Lepomis macrochirus macrochirus Common bluegill Rafinesque. L. cyanellus X‘l: macrochirus Green sunfish X bluegillS :E; gibbosus X.L; macrochirus Common sunfish X bluegill 1 Listed in 1935. Believed to have been introduced by bait fishermen. The fish probably did not reproduce in the lake. None were found 2 in 1951. \nc'w Not listed in 1935. In 1951 this fish was common in the shallow outlet area of the lake. Listed in 1935 as rare. Not found in 1951, but probably present. Not listed in 1935. A green sunfish X common bluegill hybrid was tagged by Shetter andehitlock in 1936. Dr. A. E. Staebler, pres— ent director of the sanctuary, reports catching the green sunfish in 1950. The fish is probably present, but rare. MARKING PROCEDURE Although a study of the population was the primary purpose of this investigation, information on movement of fish within the lake was gathered with a minimum of additional work. Stakes were placed at four points on shore so that imaginary lines drawn between opposite pairs would divide the lake approximately into quarters. See Figure l. Quar- ters were symbolized as Right Pectoral, Left Pectoral, Right Ventral, and Left Ventral Regions to correspond to the fin clipped from fish caught in each area. These regional titles will be abbreviated to RP, LP, RV, and LV throughout the remainder of this paper. Respective acreages of the regions were as follows: RP, 10.30; LP, 10.06; RV, 8.80; and LV, 10.17. Fish caught by angling in a given region were marked by removal of the appropriate fin and an additional cut of one half of the soft dor- sal fin. If the fish was captured in a trap or hoop net, the regional mark was applied, but no dorsal cut was made. If a fish marked as caught by angling was recaptured by angling in a different region, a' new regional mark was added; fish recaptured in the same region had the whole soft dorsal removed; if recaptured a third time, one half of the spiny dorsal was cut. If a fish originally caught by angling was recaptured by netting, one half of the anal fin was cut. 'When a fish first caught by nets was recaptured by angling, both one half dor- sal and one half anal cuts were made, and the appropriate regional mark added. Marking of fish began on April 21, 1951. From this date to May 27 17 almost all fish marked were caught by hook and line. No record of fish caught per man hour was kept, but the number would be high. This investigator was usually accompanied by another graduate stu- dent in fisheries from the College who acted as data clerk. 'When fish— ing was slow, total and standard length, weight, and sometimes scale samples were taken as soon as the fish was caught. The fish were fin- clipped according to the system outlined above and released. 'When a fish seemed moderately injured, it was not released. ‘When fishing was good, the fish were placed in ten gallon milk cans until about five fish were in the boat which would require about five minutes. Then the fish were measured, weighed, fin-clipped and released. Fish caught by angling were always released within fifty yards of the place they were caught and always within the quarter boundary. Fish captured by nets were placed in ten gallon milk cans. 'When the cans were filled to a safe capacity, the boat was moved to the intersection of the dividing lines in the center of the lake and anchored. There data was taken and the fish released as rapidly as possible. Any fish in doubtful condition was not released. The object of having a central release point was three-fold; to attempt to insure a random redistribution of the fish, to eliminate a concentration of marked fish surrounding the net, and to provide a com- parison of movements between fish released at their point of capture and those released at a central station. This last objective met with limited success due to varying sus- ceptibility of a species to angling and netting. A large number of largemouth bass were captured by angling whereas a small number were 18 taken in the nets. The situation was reversed with the bluegills, pump- kinseeds, and bullheads. Recaptures of other species were made in insuf- ficient numbers to yield any significant data. Consequently, informa— tion on fish movement was only adequate on one phase of the comparison 1333b. 19 METHODS OF CAPTURING FISH Angling Spring fishing for largemouth bass was done almost entirely by bait- casting and flyrod with artificial lures from April 21 to the middle of May. From the middle of May to the end of the month, minnows were found to be the most successful bait. During the months of July, August, and September most angling was with plugs and flyrod surface lures. Large numbers of bass were caught by angling during April and may. All fish became increasingly difficult to catch after June. There was an increase in per unit of fishing effort, but a drop in catch. Occasion- ally throughout the summer, good catches of panfish resulted from bait fishing with earthworms, small minnows, and catalpa worms. After the opening of the statewide lake fishing season, Dr. A. E. Staebler, director of the sancturary, gave a limited number of people permission to fish the lake if they agreed to cooperate with the creel census. The lake was ideal for census work, as the only boats were located in a boathouse at the outlet on the east shore. These people were permitted on the lake once or twice during the summer. One man, mr. KellOgg's chauffeur, was given unlimited fishing privileges. Whenever possible, the writer checked the fish being removed from the lake for marks. Some anglers were careful in their examinations and results were gratifying. Others did not see as many as three fin—clips from a catch of hO bluegills. If a large number of marked fish left the lake without my knowledge, the results of the population estimate would be high. The error resulting from anglers' carelessness is not thought 20 to be significant when the overall weaknesses of population estimations are recognized. The following is a condensation of the rules to which all anglers fishing the lake agreed. Cards and pencils were provided. A large printed picture of a bass was posted with all fins labeled. A study to determine the total population of the fish in this lake is underway. In order to iliminate discrepancies in the data it is requested that all persons record the number and species of fish caught. Examine your catch and note if the fish have been fin-clipped in any way. An ideal sample report is filled out below. Remember to state how many fish and what kind were removed from the lake. Netting Hoop nets were used a few times during the spring. Their rate of capture was far below the rate of capture by angling. Time spent in setting the nets would have been more profitably spent in angling. The nets were of the standard type, netting stretched over a series of hoops which were connected by funnels of mesh. There were 6 hoops, tapering from a diameter of 3 feet to 1 foot 8 inches. 'Wings and body were each 9 feet long. ‘Wings were 3 feet deep. All mesh was 2 inches stretched measure. During the late spring and throughout the summer, Great Lakes trap nets were used. See Figure 2. A hundred yard lead, h feet deep, was attached to the net, but usually most of it was placed on shore and not used. Wings, leader, and hearts were of 2.5 inch stretched mesh and the cars were of 1.5 stretched mesh. Figure 2. Great Lakes Trap Net. Description on Page 20. mmo>mr 2 l/Z" MESH W W V «2“» x ,4.’ A 41 \\ 4:1, OPENING—PMN\‘.-5' . .3: 7 V ~ , A .. x /, II/2 MESH \\ 5"! \\{I’ W 07$ Io' 4—6 ——v- V V TABLE III 23 NETTING-RECORD Set Time in No. of Depth Number Mortality Date no. days lifts of set Species caught No. A. Hoop Nets I-J April 29 1 1 1 8' YBH 5 0 0 May it 2 1 1 10' YP l 0 0 May 14-6 3 3 3 5' BG 3 0 0 CS 2 o 0 KB 1 0 0 May 5-6 h 2 2 ‘ 12' mm 1 o o YBH 1 1 100* May 13 5 2 1 9' YBH 2 2 100* 6 2 1 11' YBH 1 1 100* LMB 1 0 0 May 18-19 7 2 2 13' ——— _ - .— 2 2 8' BG 2 o 0 cs 2 0 0 B. Trap Nets May 211-27 1 2%- l 15' 1MB 11 2 18 B0 28 o 0 cs 2 o 0 KB 1 o 0 YP u 0 0 YBH 20 2** 10 Amia l2 2** 17 July 2-h 2 2 1 10' 1MB 2 2 100 130 2 2 100 KB 1 1 100 IF 2 2 100 YBH 7 7 100 July 1-5 3 L31,- 2 6' L123 3 0 0 .‘ BG 7 1 114 CS 2 0 0 YBH 9 o o Amia 1 o 0 July h-S h 1 1 9' mm 2 1 50 BC 5 0 0 CS 5 0 0 YBH 7 0 0 Amia 2 2 100“"6 July 5-10 5 5 2 6' 11m 8 1 13 BC 78 5 6 cs 35 6 17 KB 21 5 21. YP 3 3 100 new 17 0 o Amia 3 3 100*“ TABLE III (Cont.) 2b NETTING RECORD - :- r _: Set Time in No. of Depth Number Mortality Date no. days lifts of set Speciesl caught No. July 5-10 hA 5 l 7' LMB 10 O 0 V BC in 7 111 CS 12 h 33 KB h 0 0 July 10-18 6 7 2 8' 1MB 5 2 hO BG 53 27 51 cs 12 b 33 KB 2 O O YP 1 l 100 Amia 2 2 100*“ July 10-18 7 7 2 7' 11113 5 o 0 BO 166 its 27 CS 55 2h M: KB 25 9 36 YBH 9 O 0. Amia l 1 100*“ July 18—25 8 7 l 10' 1MB h 2 50 BG 30 13 113 CS 22 15 68 KB 1 O 0 IF 1 l 100 YBH h 0 O Amia l O 0 July 18-25 9 7 1 53' mm 1 o 0 BG h8 h 8 CS 33 0 0 KB 9 O 0 108 l l 100 Amia 1 0 0 July 25-Aug. l 10 7 l ' 7' LMB 10 h to 80 5h 22 bl cs 143 to 93 KB 1 l 100 IF 1 0 O YBH 5 0 0 July 25-Aug. l 11 7 l 5' LMB 3 O 0 BG 35 1 3 CS 2h 9 38 KB 8 l 13 IF 2 l 50 YBH 8 l 13 Aug. 1-8 12 7 l 5' 1MB 6 l 17 ‘ BG 7 h 57 YP 1 0 0 YBH 8 O O Amia 3 l 33 TABLE III (Cont.) 25 NETTIN G RECORD I r Set Time in No. of Depth Number Mortality Date no. days lifts of set Species:L caught No. Aug. 1.8% 13 7 1 5%! LMB 2 2 100 YBH 10 O 0 Aug. 8-16*""“"“* 111 8 l 6' BG 7 0 0 CS 1 0 0 Aug. 8-15 15 7 l 7' LMB 18 l 6 BG 113 39 35 CS 55 27 149 KB lb 5 36 YP 5 5 100 YBH 27 1 h Amia 3 3 100 1 Species abbreviations are LMB, largemouth bass; BG, common bluegill; CS, common sunfish or pumpkinseed; XB, common sunfish X common blue- gill hybrid; YP, yellow perch; YBH, yellow bullhead; Amia, bowfin; and LCS, western lake chubsucker. * Removed for stocking experimental ponds of Michigan State College at lake City, Michigan. H- Placed in exhibition tanks of Kellogg Bird Sanctuary. W Killed for stomach analysis. 7 {31-H- A large rip in the top of the net permitted escape. **%** This net set did not fish correctly. 1': a .1 .Ta 0 m . .C «Q 9» ml .u Mad 3 R E G «M 1%....” ~. era Jf 1 . n L ..h TABLE IV 26 TOTAL MORTALITY AND YIEID FOR SPRING AND SUMMER, 1951, WINTERGREEN LAKE Species and Average Method of time of Number Mortali§y 'weight Total Pounds capture capture caught No. in grams yield per acre Hoop Net LMB 2 O 0 BG 5 O 0 CS h 4 O 0 KB 1 0 0 IF 1 O O YBH _2 u uu* 521.3 u.6 .12 Total 22 '11 1'8 TIE . 12 Trap Net LMB 90 18 20 327.h 13.0 .33 BC 680 170 25 203.h 76.2 1.9h CS 301 129 h3 l7h.2 h9.5 1.26 KB 87 22 25 176.9 8.6 .22 YP 20 13 65 150.1 h.3 .11 YBH 131 11 8** 521.3 12.6 .32 Amia 29 lb 1.8“” 1611.3 h9.7 1.26 IDS l 1‘ 100 260.0 .6 .02 Total 1339 '378***28*** 215.5 5.55 Angling LMB Before 6-25 1029 27 3 327.8 19.5 .50 After 6-25 339 llhg .22 102.5 2.61 Total 1368 169 12 122.0 3.10 30 Before 6-25 70' 6 9 203.h 2.7 .07 After 6-25 7&8 572 16 256.5 6.52 Total 808 '578 71 2 9.2 6159 CS Before 6-25 15 6 hO l7h.2 2.3 .06 After 6-25 .192 82 80 31.5 :89 Total 117 88 ‘75 33.8 .86 KB Before 6-25 1 0 0 176.9 After 6-25 2 3 8 _3_5_ i1 . 08 Total 2H 8 33 3.1 -:O8 YP Before 6-25 77 5 6 150.1 1.7 .Oh After 6-25 lb8 120 81 9.7 1.01 Total 225 125 '56 81.5 1.0 YBH After 6-25 6 6 100 521.3 6.9 .18 Amia 5 h 80 1611.3 lh.2 .36 Total 2 63 978 '38 580.6 12.22 Dead fish on shore 63 32.1 .82 Grand total 392k 1h59 37% 731.8 18.61 l Explanation of abbreviations found in footnote 1, Table III. * Removed for stocking experimental ponds at Lake City, Michigan. ** Eight Amia were killed for stomach analysis, two were placed on display, and two bullheads were displayed in the sanctuary aquarium. *** Corrected for intentional deailh, would read 366 and 27 percent. 27 A rowboat was the most suitable craft on the lake for setting and lifting nets. It would have been desirable to release fish from the nets at least twice a week, but the nets were allowed to fish a whole week on numerous occasions. Two men were required to lift the nets, measure and weigh the fish, and move the nets. There were no funds available to employ help. Local high school students and other interested persons supplied the necessary labor. Their reward came in fishing hours on the lake. 28 COMPARISON OF FISH CAUGHT BY ANGLING AND BY TRAP NETTING Hansen (l9hh) observed the rate of escape of fishes from hoop nets. His results showed that common bluegills and largemouth bass exhibited a remarkable facility for escape when left in the nets for a day or more. In one day sets in Maple Lake, Illinois, he used 81 bluegills, of which 32 percent escaped. One day tests at Lake Glendale, Illinois showed 36 percent of hh bluegills escaped while 37 Percent of L6 bass escaped. Fifty-one hour tests in the same lake resulted in 86 percent of 36 blue— gills and 20 percent of 51 bass escaping. He writes that fish do not seem to realize they are in traps. They are very calm and do not seem to search for the exit. The fish merely swim in and out of the trap. It would seem that fish trapped in a large enclosure such as the trap nets used in the present study would not become excited at all and.would use the net as a shelter. The above hypothesis does not seem tenable when the mortality rate of trap netted fish in this experiment is considered. See Table IV. Although Hansen states that the fish do not swim wildly about the net in a manner conducive to injury, much of the mortality in trap nets used in this experiment seemed to be caused by physical injury. Visual evidence of tail wear and abrasions about the head Were present in many fish. These abrasions gave fungi an opportunity to enter. Although guppies, Lebistes reticulatus, succomb peacefully to oxygen deficiences, (Ball, verbal communication), perhaps the species in these trap nets did not. Snapping turtles, Chelydra serpentina, and bowfin present in the nets may have caused panic among the trapped fish. Eight bowfin were re- 29 moved from trap net sets 3, 5, 7, 9, 10, and 11. Two of these turtles were too decomposed to work on, but the other five were examined for stomach contents. All five stomachs were packed with fish. Visual and olfactory clues indicated that the fish eaten had been carrion. There is no proof of this statement and it is possible that the turtles consumed live fish, but it seems more likely they preyed on the dead ones. In all cases the fish remains had never passed the junction of the stomach with the duodenum. The intestines were filled with filamentous algae, molluscs, and other bottom organisms. It is unknown whether the presence of these predators in the nets had any effect on the entrance of fish into the trap. Aquarium reac- tions of fish of the size caught in the nets to the bowfin and snapping turtle are indifference. Reactions in the natural environment of the lake may be different. An effort was made to compare the condition of trapped fish with fish caught by angling. This comparison was not planned and informa- tion on the point was collected incidentally to the primary purpose of the experiment, namely population study. Only fish that were judged to be in releasable condition were considered for the test. No data were taken from dead fish or fish with more than a slight fungus infection. Condition factor for the fish of the two groups was found by the formula: K = Weight X log/Length3. 'Weight in grams and standard length in millimeters were Substituted in the formula. Standard length was used because of worn caudal fin tissue on some of the trapped fish. It has been recognized that the value of K is not constant for an indi- vidual fish, species, or a population. However, I believe condition 30 factor is valid when used for comparison purposes between two groups of fish of the same species from the same population, provided the compari- son extends over the same period of time. The t test was used to compare fish removed from trap nets with those captured by angling, following methods presented by Dixon and Massey (1951) for testing the hypothesis that two samples, differing as much as those being examined, might have been drawn from the same population. It would have been desirable to compare each species over a short period of time, but sampling was not adequate. Bluegills were the only fish adaptable to this periodic comparison. For this species, three time-periods during spring and summer were established, 3 , July, and August. Measurements were divided into 7 standard length classifica— tions within the range from 10.75 to 21.25 centimeters. Class midpoints were 11.5, 13.0, 1h.5, 16.0, 17.5, 19.0, and 20.5 centimeters. Each class limit was .75 centimeters above and below the midpoint. Results are presented in Table V. This table suggests that largemouth bass, common bluegills, common sunfiSh, and the common sunfish X common bluegill hybrid may suffer a weight loss while in the nets. All condition factors for largemouth bass, common sunfish, and hybrid sunfish were not utilized in this ex— periment. ‘When a large quantity of data for an individual species of the same size over a short time—period were available, taken either by angling or netting, but not by both, fish were selected by picking only the second and fifth fish in a series of five. However, all available data for bluegills were used. The t test was applied to all time periods TABLE V 31 COMPARISON OF K FACTOR OF FISH CAUGHT BY ANGLING AND BY NETTING Hypothesis: Condition factor of fish caught by angling has the same condition factor as fish caught by netting. Standard Method Mean of Time length in of K Observed Species period centimeters capture N factors t value Largemouth bass 5/25-8/16 All fish Angling 18h 2.226 Netting ._H§ 2.180 V 228 2.98”* Common sunfish 5/h-8/16 All fish Angling 32 5.233 Netting 172 5.01h 258 2.52* Com'n sunfish X 5/h-8/l9 All fish Angling l9 5.68h bluegill hybrid Netting 63 5.316 82 3.38** Common bluegill 5/3-27 13.75-15.25 Angling l2 h.589 Netting .11 b.657 23 “0314 5/3—27 15 .25-16.75 Angling 35 11.902 Netting ‘11 b.58h 52 2.55* 5/3-27 16.75-18.25 Angling 7 5.106 Netting ‘_h h.876 11 1.8h 7/3—26 12.25-13.75 Angling 10 b.6h9 Netting _:_L__7_ b.1791 27 1.25 7/3-26 13.75-15.25 Angling 5 b.822 27 2.79** 7/3-26 15.25-16.75 Angling h3 b.852 Netting 203 b.880 , 2116 8.88”” 7/3-26 16.75-18.25 Angling 20 b.821 Netting .72 h.h76 ** 99 n.85 8/1-28 13.75-15.25 Angling 11 h.680 Netting '12 h.383 , 30 1.35 8/1-28 15.25-16.75 Angling 36 b.5u6 Netting A6 b.533 ' 82 .01 8/1-28 16.75-18.25 Angling 29 u.t51 Netting .61 h.386 90 .5h 5/3-8/28 All Angling 220 n.715 Netting 51h h.h68 7311 8.39” * Significant at the 95 percent level of confidence. ** Significant at the 99 percent level of confidence. 32 and length groupings in which a minimum of four fish was taken by each of the methods, netting and angling. In only one case, from May 3 to May 27 in the 13.75-15.25 centimeter group, did the mean K factor of trapped fish exceed that of fish taken by angling. These netted fish were captured in hoop net sets of short duration and in one trap net set of 2.5 days. The difference was small and not significant, statis- tically. There was little opportunity for their condition factor to drop.‘ 'When all data are combined for bluegills, irrespective of size or date, then the difference between trapped fish and those taken by angling is highly significant, statistically. If the mortality which took place was due to oxygen deficiency it seems likely that the fish would have died'within a short period. They should not have shown signs of being in the nets a long time. Since the netted fish exhibited such signs as tail'wear, abrasions, and a drop in condition factor it seems probable that they had spent at least three days in the trap. The question of whether net mortality was caused by lack of oxygen or length of time in the net is still un- decided. It seems apparent that the fish taken in trap net set No. 2 died from a lack of oxygen, but the mortality in other sets probably resulted from.a combination of oxygen deficiency, net-caused abrasions, lowered physical vitality, and fungus infections. 33 MOVEMENT OF FISH Review of Previous Investigations Many investigators have performed lake population studies by the mark and recapture system. However, very few have attempted to keep data on horizontal movements of warm water species within the lakes studied. The purpose of most movement studies has been to follow spawn- ing runs or to obtain information on migration and survival of stocked fish. A statistical analysis of these movements has been attempted by even fewer workers. This section of the paper will be devoted to a statistical analysis of horizontal movements of largemouth bass, common bluegills, common sunfish, yellow bullheads, bowfin, yellow perch, and the common sunfish X common bluegill hybrid within'Wintergreen Lake. Ball (l9hh) divided the shoreline of Third Sister Lake, Michigan into 100 foot sections. All fish tagged in this experiment were re- leased at the point of capture. By this method it was possible to locate the point of capture and release of fish within ten yards. Only fish recaptured fifteen days or more after time of tagging were con- sidered. Area of the lake was approximately ten acres. His results appear below and on the following page. TABLE VI SUMMARY OF MOVEMENT OF TAOCED BLUEGIIIS IN THIRD SISTER LAKE (BALL, l9hh). Number Of fish Movement from point Time between tagging Percentage of recaptured of tagging (yards) and recapture (days) fish recaptured 12 0 Mfiaflf DD h 30 16-3h3 lh.8 2 65 301-hob 7.h h 65-150 37-370 lh.8 5 lSO-plus 20-39h 18.5 3h TABIE VII SUMMARY OF MOVEMENTS OF BUIIHEADS IN THIRD SISTER IAKE (BALL, 19th) Number of fish Movement from point Time between tagging Percentage of recaptured of tagging (yards) and recapture (days) fish recaptured 11 0 lS-h32 39 A 15-30 331-380 1h 8 30-100 h6-h35 28.6 h 100 plus BSO-AS? lb From these tables it can be seen that about 60 percent of the tagged bluegills were recaptured.within 30 yards of the point of orig- inal capture. Fifty percent of recaptured bullheads were taken within 30 yards of the point of original tagging and 81 percent within 100 yards. Ball also states that all of the bullheads recaptured more than once were taken at the same location each time, even though intervals between captures were severa1.weeks or months apart. These data seem to' indicate a strong territorial tendency of these fish in this small lake. His information on largemouth bass shows that the 7 individuals recaptured of 56 marked had roved over the entire lake and showed no tendency of having a home range. Four of these fish were retaken more than once, and one was recaptured h times. Ball reports that nearly every bullhead and largemouth bass in his nets was gorged with fish. Perhaps the movements of these often recaptured fish were influenced by availability of food in the nets. Rodeheffer (l9hl) presented information on movements of northern rock bass, Ambloplites rupestris rupestris (Rafinesque), yellow perch, common sunfish, smallmouth bass, Micropterus dolomieu dolomieu Lacepede, 35 largemouth bass, and northern pike, Esox lucius Linnaeus in Douglas Lake, Michigan. His data were compiled over three summers while he was work— ing on effect of brush shelters in the lake. Over 90 percent of his original captures and recaptures were made by seine in the eastern end of the lake. He released some of his marked fish in unfamiliar territory, but always fairly close to the point of original capture. The great majority of releases occurred at the capture point. He summarized that of all fish marked at several locations and freed in their home terri- tories, none were retaken in distant parts of the lake. He concludes that there was little movement of marked native game fish in the eastern end of Douglas Lake. All brush shelters were at this end of the lake and they may have had an influence in attracting and keeping fish in that sector. These results are not similar to other investigations. Douglas Lake is a large body of water over h miles long. However, this would not seem to limit the wanderings of the fish population. Reference to two of Rodeheffer's previous publications (1939 and 19h0) disclose that fish upon which he based his assumptions were over 95 Percent young of the year, yearlings, and other fish smaller than those considered in this study. Perhaps the species included in these reports change their territorial habits when they reach maturity. It would be expected that juvenile fish would tend to remain in the location offering the most protection and would not need to forage widely to satisfy their require- ments. Schumacher and Eschmeyer (l9h2), a statistician and a fisheries biologist, combined their talents in a statistical analysis of movements 36 of largemouth bass, smallmouth bass, and Kentucky bass, Micropterus punctulatus punctulatus (Rafinesque), in Norris Reservoir, Tennessee. Eschmeyer marked and released 662 largemouth bass, 187 smallmouth bass, and 75 Kentucky bass from April 3-May 16, l9h0. All captures were by angling along 1 mile of shoreline of Cove Creek, an arm of Norris Reservoir. During the 200 day period following this marking, data were collected from 121 recaptured largemouth bass, 2? smallmouth bass, and 30 Kentucky bass. Summarization of the movements are best explained in the authors' words. " ..... smallmouth bass travel much less than either large- mouth or Kentucky, 90 percent of the smallmouth having been distributed within a distance of two miles from the point of tagging by the 15th day, within 3 miles by the h0th day, and within 3.3 miles by the end of the fishing season. Large- mouth bass traveled farthest and most steadily, 90 percent of them having spread over a distance of h.7 miles by the 15th day, 10.5 miles by the hOth day and 16 miles by the end of the season. The 'spread' of Kentucky bass was, by the end of the season, intermediate between that of the largemouth and smallmouth, 90 percent having spread within a distance of 7.6 miles from the point of tagging." Manges (1950) presents further results of similar experiments con- ducted in Norris Reservoir and Cherokee Reservoir from 19h6-19h9. In Norris Reservoir the average distances, measured in a straight line be- tween points of capture and recapture, covered by 29 largemouth bass for tlie years l9h7, 19h8, and 19h9 was h.3 miles; by 11 smallmouth bass was 2.2 miles; and by 5 Kentucky bass in l9h9 was 5.8 miles. If Eschmeyer's averages are included, all distances are lowered slightly. The com— bined results yield the following average distances travelled: 150 large— mouth bass, h.0 miles; 38 smallmouth bass, 1.2; 35 Kentucky bass, 3.6. 37 Only one second-season recapture was made for these three species and it is not included in the results. manges' investigations on Cherokee Re- servoir for 19h? and 19h9 show 11 largemouth bass moved an average of h.7 miles. These results on movement of bass are not applicable to any re- search reported in this paper because the bodies of water are not com- parable. Norris Reservoir has a shoreline of over 700 miles while Wintergreen Lake has a total area of LO acres. It is interesting to note that previous investigations have indicated that largemouth bass exhibit very little territorial tendency and are inclined to be wanderers. Re- sults of study on Wintergreen Lake do not seem to bear this out. Dr. Gerald P. Cooper in Report No. 1298 of the Michigan Institute for Fisheries Research, in press for Transactions of the American Fish— eries Society, Volume 81, 1951, presents data on movement and popula- tion in two Michigan lakes. It is with his permission that information presented below is reviewed. Sugarloaf Lake has a surface area of 180 acres. The lake is uni— formly shallow, between 2 and 5 feet deep, with a very small area over 10 feet deep and a maximum depth of 21 feet. An imaginary line dividing the lake on a north-south axis was es- tablished. Similar trap netting patternstwere operated in each half. General procedure was to fish several nets on a systematic schedule at numerous stations for four to six weeks. All captured fish were re- corded and marked with a regional fin-clip. A Single central release station was located over the deepest part of the lake. There were three netting periods on Sugarloaf Lake: 19h8, October 38 20-November 2h; 19h9, April 20-May 22; and 1950, April 18—June 1. Over the three periods 12,2h6 fish were marked. Cooper found homing tendency of the fish to be consistent for both halves of the lake. Fish marked in the west half tended to return to the west half and fish marked in the east half tended to return to the east half in two of the three periods, but in l9h8 fish marked in both halves tended to be recaptured in the east half. There were h98 more fish recaptured in their home half than in the opposite half. For purposes of comparison, these results have been broken down in Table VIII to include only species studied in Wintergreen Lake. All data are totals for three years of study. TABLE VIII ANALYSIS OF RECAPTURES OF MARKED FISH IN SUGARLOAF TAKE Number Same Opposite Preponderance Species recaptured half half of homing fish Largemouth bass 5h 39 15 2h Common bluegill 1015 603 h12 191 Common sunfish 95 79 16 63 Yellow perch 15 7 8 -1 Yellow and brown bullhead 801 th 359 83 Bowfin 83 57 26 31 Dr. Cooper states that the combined preponderance of 18 percent seems inconsequential as a source of bias in his population estimates. He feels that the preponderance may have been only partly an expression of homing t0 the original netting site and that the extensive netting 39 pattern would compensate for it. He concludes that, ".....Most of the fish redistributed themselves over the lake generally and did not return quickly to a home niche." Table IX, a Chi2 test as outlined by Simpson and Roe (1939), which measures differences between theoretical and observed frequencies of occurrence, suggests that Cooper's data indicate that all species listed, with the exception of yellow perch, did not distribute themselves ran— domly over the lake when released from a central location. The tests shows that there is less than 1 chance in 100 that distribution from the central release station was random. The homing tendency seems well de- fined as illustrated by Table IX, presented on page hO. Five hundred and seventy-five acre Fife Lake was the second lake included in Dr. Cooper's report. The lake was divided in half by imaginary lines on a northeast-southwest axis and each half was trap netted with a similar systematic pattern from June 16 to July 19, 1950. Two release stations were established, one in the center of each lake half. Odd and even—numbered netting stations were evenly distributed in the netting pattern. Captured fish were given a mark (fin-clip) dis- tinctive for their half of the lake and for either the odd or even- numbered trap net station where they were caught. All fish were returned to the lake at the release station in their home half. Of 5,6hl fish marked in the lake, 309 were recaptured. Dr. Cooper considers that data for Fife Lake support two conclu— sions. (l) Recaptured fish did not show a predominant tendency to be re- captured at their home net Site, either odd or even numbered. TABLE IX CHI2 TEST OF REDISTRIBUTION OF MARKED FISH IN SUGARIOAF LAKE j 1 t— -—‘ Hypothesis: Redistribution of fish is random from central release. I Recaptured I Recaptured I I I In I in Opposite I Total re- I Observed Species I home half I half I captures I Chi2 I I I I I I I I I 27 I 27 I I , Largemouth bass I / I / I 5n I 10.66” I 39 I 15 I I I I I I I I I I I 507.5 I 507.5 I I Common bluegill I / I / I 1015 I 35.9h** I 603 I blZ I I I I I I I TI I I I h7.5 I h7-5 ' ' ** Common sunfish I / I / I 95 I hl.78 I 79 I 16 I I I I I I I I I I I 705 ' 705 I I Yellow perch I / I ./ I 15 I .06 I 7 I 8 I I I I I I T r I I Yellow bullhead I h00.5 I h00.5 I I ** and I / I / I 801 I 8.60 Brown bullhead I hh2 I 359 I I f I IV I I h1.5 I h1.5‘ I I . Bowfin I / I / I 83 I 11.58” I S? I 26 I I I I I I I I I I l IlBhl I13hl I I y All species I I I 2682 I 92.h7”* I 1590 I 1092 I I I I I I ** Significant at the 99 percent level of confidence. 1 Includes other species not shown above. to III (2) Fish were recaptured approximately twice as frequently in the same half of the lake where they were originally captured as in the opposite half. Since two release stations were utilized, this prepon- derance was expected. He measured average distances in hundredths of a mile between re- lease stations and odd and even—numbered stations in each half and mul- tiplied them by the corresponding figures for percentage of recapture of all species in each type of net set, i.e., east-even, west-odd, etc. This resulted in a migration index he could compare statistically. He concludes that the tendency for fish to be recaptured more frequently in their home half was mostly a function of distance from release sta- tion to the recapture netting site, rather than homing instinct. 'Wintergreen Lake Results Methods of marking fish in'Wintergreen Lake are outlined in the section on Marking Procedure. Movements of the species will be taken up separately. Explanation of movement diagrams The labels of the h quarters of the charts correspond to quarters of the lake. Fish captured in any of the regions were marked by clip- ping the appropriate fin. Numbers appearing outside the quarter, above or below the regional label, indicate the number of markings re- observed from that region. Squares inside the quarters Show the number of regional cuts reobserved in their respective home region. For ex- IIZ ample, in Figure 3a there were h8 RP regional marks reobserved. Of these, 26 were reobserved in their home territory, 6 moved to the LP Region, 7 to the LV Region, and 9 moved to the RV Region. Since there were unequal numbers of recaptures from the various regions, these discrete numbers offer little basis for comparison between the regions. To enable a comparison to be made, percentages were utilized in the following figures whose numbers are followed by a "b". This permits easier evaluation of movement patterns. For instance, Figure 3b shows that of the h8 RP regional marks reobserved, 5h percent were taken in the same region where they were originally marked, 12.5 percent moved to the LP Region, 15 percent moved to the LV'Region, and 19 percent to the RV Region. The number of marks does not necessarily correspond to the number of fish marked, for some carried two or three marks. If a fish with right ventral and right pectoral fins removed was recaptured in the LP Region, the data were tabulated with two observations; one reading that the fish had been originally marked in the RV Region and had moved to the LP Region, and the second reading that original marking had taken place in the RP Region and movement had been to the LP Region. 'When a fish bearing both angling and netting marks was recaptured, movement was recorded both for net and angling marked fish. 'With this method- ology in mind, the following charts and tables are presented. II3 Largemouth bass More data on migration of this species were collected than for any other. There were 1,101 regional marks made from April through August on released bass. Of these, 317 were made in the RP Region, 197 in the LP, 22h in the RV, and 363 marks were made in the LV Region. Most of these represent angling caught fish, the divisions being 310 caught by angling and 13 by net in the RP Region, 186 and 11 in the LP, 211 and 13 in the RV, and 339 caught by angling and 2h by net in the LV Region. During the period of early spring angling, most largemouth bass were captured in shoal areas of the RV and LV'Regions. After the lake was stratified thermally, greatest angling success was realized in the drop-off area of the RP and LP Regions. This unequal distribution was presumed to enter some bias on results of the Chi2 test in Table X. To offset this supposed influence, data were split into two periods, April and May, and June, July, and August. Results were surprisingly similar for the two periods, as shown by succeeding tables and figures. A Chi2 test, following the same procedure and hypothesis presented in Table X, was applied to data of Figures ha and 5a. The sum of the Chi squares for ha was 35.9h and 30.h5 for 5a, both highly significant at the 99 percent level of confidence. Thus the hypothesis of complete independence in redistribution is not acceptable. This is expected, for fish were released at the point of capture. As was the case in Table X, the number of recaptures taken in their 2 home quarters contributed the largest sums to the Chi total. In Figure ha the RV'X RV cell was responsible for 18.h7. The other three home Figure 3a. Actual numbers indicating where regional marks were reobserved. Largemouth bass originally caught by angling, Wintergreen Lake, April — August, 1951. 48 54 RP LP REGION REGION 26 >6 19 14: 5 13 22 II 31 II v '7 v 9 10 11 +8 28 1221* 57 RV LI, REGION REGION 54 102 Figure 3b. Percentages indicating where regional marks were reobserved. Largenouth bass originally c uzht bv angling, "intergreen Lake, April - August 19: e es were derived by multiplying the recip- tual umbers of reobserved regional marks by This results in per— the actual numbers indicating movement. The hypothesis centages that may be compared between regions. necessary to make this supposition is that 100 fish originally captured by angling were recaptured from each region. 48 54:: RP L REGION REGION ‘54 >12 35 264 9 22 l4 3K) II II /\ 15 II 19 / 19 20 —>-15 52 124 36 RV LIV REGION REGION 54 102 47 CH12 TEST FOR INDEPENDENT REDISTRIBUTION OF “TGIONAL MARKINGS TABLE X ON LARGEAOUTH BASS CAUGHT BY ANGLING, AIRILPAUGUST, 1951 Sum of the Chi squares is 55. 72. Table value of Chig with 9 de- Hypothesis: Fish captured by angling and released in their home territory redistributed themselves over the lake with complete independence. Region Where Recaptured R I RP I LP I RV I LV I SUM E I I I I I G I 15.6 I 9.7 I 11.2 I 11.5 I I RP I / I I / I I Q I 26 I 6 I 9 I 7 I 148 N I I I I I I I I I I 'W I 17.6 I 10.9 I 12.6 I 13.0 I H LP I / I / I / I / I Sh E I 1h I 19 I 11 I 10 I R I I I I I E I I I I I I 17.6 I 10.9 I 12.6 I 13.0 I :5 RV I / I / I / I / I SD A I 13 I S I 28 I 8 I R I I I I I { I I I I I E I 33.2 I 20.6 I 23.7 I 2h.5 I 13 LV I / I / I / I / I 102 I 31 I 22 I 12 I 37 I I I I I I I I I I I SUM I 8h I 52 I 60 I 62 I 258 I I I I I Theoretical frequencies are entered in the upper left corners of the cells. Observed frequencies are entered in the lower right cor- ners. method from Simpson and Roe (1939). grees of freedom is 21.67 with a 99 percent confidence limit. table indicates that the bass did not distribute themselves randomly and independently after release in their home region. is rejected. The hypothesis h8 The sum of the h Chi squares for the home regions is 38.15, or an Average of the other cells is l.h6. average of 9.5h. from the expected. This suggests that the territorial tendency was responsible for the large deviation Figure ha. Actual numbers indicating where regional marks were reobserved. Largemouth bass originally captured by angling, Wintergreen Lake, April and Hay, 1951. 22 29 RP LP REGION REGION 10 >4 11‘ 8 < 3 2 1 II 2\> I? II /> 3 II 5 6 4 *3 15 a 1;] RV LY REGION REGION 23 62 Figure Lb. Percentages indicating where regional marks were reobserved. largemouth bass originally captured by angling, Wintergreen Lake, April and May, 1951. 63mm 2 29 p LP ION REGION 45 4—- 18 58 13> 14 >15 55 11: 51 RV LIV. REGION REGION 25 ' 62 52 Figure 5a. Actual numbers indicating where regional marks were reobserved. Largemouth bass originally captured by angling, Wintergreen Lake, June, July, and August, 1951. 3% ES REGION REGION 16 e 2 8 6: 2 1 '7 IIL 10\> II II ® 4 II 4 4 7 $5 13 5< '18 RV LV REGION REGION 51 4O Percentages indicating where regional marks were reobserved. La. captured by angling, Wintergreen Laxe, June, July, and August, 1951. "genouth bass originally U7 0\ 25 25 RP LP REGION REGION 62 ' =ra 52 244: 15 ;// 15 I6 28 >16 42 15 4 45 RV LN REGION REGION {51 4O 57 cells averaged 1.91, while all other cells averaged 0.90 per contribu— tion. Data from Figure 5a were in general agreement with that from ha, except that the RV X RV cell decreased its contribution to a normal level for the home cells, whose average was b.89. All other cells averaged 0.91. The preceding information seems to support two conclusions to be drawn from the spring and summer experiment period. - (1) More largemouth bass in Wintergreen Lake were recaptured in regions other than the quarter of their original marking than were recap- tured in their home quarter, indicating that some individuals tended to utilize the whole area of the lake. However, a proportionally large per— centage of fish were recaptured in their home region. One hundred and ten of 258 regional marks on fish released in their home quarter were re- observed in that same region. This is a percentage of £2.6. This suggests that many of the largemouth bass have a territorial tendency. Apparently there are at least two behavior patterns present in the species, those that wander and those that prefer to remain in a 'home niche. (2) A general trend to move to the drop-off area on the windswept, spring-fed shore also seems evident. After eliminating the numbers of regional markings reobserved in their home quarters, 39.2 percent of the remaining 1h8 regional markings were found in the RP Region, as opposed to 22.3 percent in the LP, 21.6 in the RV, and 16.9 in the LV Region. The above figures are probably affected by the unequal numbers of re- captures made in each of the four areas. In order to minimize some of the bias, the hypothesis of reobserv- ing 100 marked fish from each region will be injected again. Proceding 58 under this supposition, the 177 regional markings reobserved in their home quarter are eliminated. This leaves 223 wanderers. Eighty (35.9 percent) of them were reobserved in the RP Region, as opposed to 51 (22.8 percent) in the RV Region, h9 (22.0 percent) in the LV Region, and h3 (19.3 percent) in the LP Region. There were only 90 largemouth bass taken by trap netting throughout the experiment. Of these, 72 were released at the central release sta- tion, bearing a mark for net caught fish. Seven of these were recaptured. This small number is not adequate to draw any conclusions concerning movement or to make any comparisons between the two methods of release for the species. Such information as was gained is presented in Figure 6. Common bluegills There were 31 regional marks reobserved on bluegills. Of these, 22 were originally captured by netting and 9 hy angling. These numbers are inadequate for drawing any definite conclusions. One general ten- dency seems common to bluegills released at the central station and in their home territory. They appear to distribute themselves around the lake without showing the predominant homing tendency illustrated by the bass. Perhaps it is mere coincidence because of the small sample, but the hypothesis of random distribution of marked fish released from both station types is statistically acceptable, as illustrated in Table XI. Data are drawn from Figures 7 and 8. Actual numbers indicating where regional marks were reobserved. gemouth bass originally captured by netting, Wintergreen Lake, Hay - August, 1951. 1 5 RP LP REGION REGION ¥ 0 3 II o > I \ . 61 TABLE XI CH12 CONTINGENCY TEST FOR INEE3ENDENT‘REDISTRIEUTION OF MARKED FISH. COMMON BLUEGILLS CAUGHT BY ANGLING AND NETTING, APRIL - AUGUST, 1951, WIN LRGREEN LAKE. Hypothesis: Released fish distributed themselves over the lake with complete indepen- dence. Method Of I Type of I Recaptured I 2 capture I release I Home quarter I Other quarter I Chi value I I I I I I I I I I 5.5 I 16.5 I Netting I Central I / I / I .55 I I 7 I 15 I I I I I I I I I Angling ' Regional ' / I / ' I I 2 I 7 I .014 I I I I Both samples fall well within the 95 percent level of confidence, and therefore the hypothesis of distribution of fish with complete indepen- dence is acceptable. Yellow bullheads Forty-five regional marks were reobserved on bullheads. All of these were originally captured by netting and therefore were released at the central release station. There were no bullheads caught by angling that were marked and released. An examination of Figures 9a and 9b indicates that the LV Region seems to be most attractive to bullheads. Eleven marks from other areas were reobserved there. Apparently this observa- tion is not too extraordinary, for a Chi2 contingency test patterned after Table XI gives a Chi2 value of 0.36, which allows acceptance of the hypothesis of complete independence in redistribution. Homing tend- 4 5 RP LP REGION REGION O: (O RV LLV REGION REG4|ON O\ IV Actual nIi-Iicers indicating wh were reobserved. Common blu :- - - V '- —.-‘ - n. ‘1'; * - A ‘ ‘v‘ . captured by angling, I-mtergreen .ar. , April - August, 1951. 65 3 2 RP LP REGION REGION >0 1 1: 1 o o A V 2 v 1 o o 41 O ‘4 0 RV LV‘ 66 ency does not seem prominent for this fish under conditions in this lake. There were 119 regional marks made and released, of which hS were reobserved. Besides indicating a low population for this species, this information suggests a high susceptibility to trap netting. Bullheads appeared to be wanderers in the lake. If the fish would ordinarily be a wanderer is not known. Perhaps abnormal behavior was induced by removal from the home niche. Miscellaneous The remaining four species were not recaptured in sufficient num- bers to indicate any definite movement patterns. The only conclusion that may be stated is that these four species, common sunfish, common sunfish X common bluegill hybrid, yellow perch, and bowfin, tended to roam over the entire lake without exhibiting a homing tendency. In most cases there were more recaptures reported than appear in the following diagrams, but information as to location of capture and regional mark is unknown; therefore, the data are useless to the movement study. Data on movements of yellow perch and bowfin may be summarized with- out the use of charts. There were only 2 yellow perch recaptured with a known regional mark. One fish captured by netting in the LP Region was recaptured in the LN'Region. One captured by angling in the LP Region was recaptured in the RP Region. Five regional marks on bowfin were reobserved. Three fish origi- nally netted in the LV Region were recaptured in the following regions, one each in the LP, RP, and RV Regions. One fish netted in the 1P Actualn nimbe ers indicating wnere regional marks were rec: serv Yellow billheads ori'inally captured by netting, Wintergreen Lake, april - Aug-us t, 1951. 4 RP REGION 11 LP REGION ’— »———h—-O V O 5\> /\ 1/ RV RECiISON L_v REGION 17 68 gr .--' "1‘I;.',$Y{_-. Figure 9b. Percentages indicating where regional marks were reobserved. Yellow bullheads originally captured by netting, wintergreen Lake, April - August, 1951. 4 11 RP LP REGION REGION 25 ——-‘——->0 56 O 4 O 23 12 II 18 II II '75 v O 55 9 +52 15 55-4 55 RV LV REEEON w RElGJON 7O 71 Region was reobserved in the RP Region and one bowfin originally cap- tured by angling in the LP Region was recaptured in the RP Region. In Figures 10 and ll fish captured by angling and netting are com- bined. The two are symbolized by an "a" for angling and a "n" for He ttiflgo Comparison of Movements of Fish in Sugarloaf, Fife, and Wintergreen Lakes Tables XII-XVIII present data comparing Cooper's results from Sugar- loaf and Fife Lakes with results of this experiment on Wintergreen Lake. The two sets of data that lend themselves best to comparison are from Sugarloaf and Wintergreen Lakes. Fish in these lakes were captured by trap netting and were released at a central station. Although Winter- green Lake was divided into quarters by imaginary lines, it was simple to convert movement data to conform with the method employed on Sugar- loaf Lake, halving the lake. The quarter system yielded two separate results, for there were two pairs of halves from which to take data, the northeast and southwest and the northwest and southeast. Each pair of halves were compared.with Sugarloaf Lake results. Statistical analysis indicated that fish redistributed themselves from the central release station in each lake in a similar manner with respect to which half of the lake they swam to, their home half or opposite half. The hypothesis that samples as divergent as these could have been drawn from the same population is accepted. See Tables XIII and XIV. Table XV utilizes a formula presented by Snedecor (1950) for deri- 'vation of Chi2 in a fourfold table. The same test may be set up for Actual numbers indicating where regional marks were reobserved. Comzcn sunfish, dintergreen Lake, lay - August, 1951. originally captured by angling are indicated by originally captured by nettilg are incicated 2 3 RP LP REGION REGION 0 >0 0 In > la 2n ‘ 0% 13. RV Ly. REEION REGION 73 Figure 11. Actual numbers indicating where regional marks were reobserved. Common sunfish X common blue- gill hybrid, Wintergreen Lake, Ray - August, 1951. Those originally captured by angling are indicated by "a", hose originally captured by netting are indicated by II II n . 1 5 RP LP REGION REGION 05% I? \>C>C>FJ H” H \Olv—‘\OCI>\OO\I IMO. Totals 112 19 Mean length 32 .116 18053 Standard devia— tion 13.5).; 31.31 1 The even centimeter is the midpoint of the class interval. 11h TABLE XXV TOTAL LENGTH—FREQUENCY DISTRIBUTION OF BOWF INS CAPTURED BY ANGLING, SPEARING, AND TRAP NETTING IN WINTaRm-mEN LAKE, APRIL - AUGUST, 1951 - I 4 L Class in centimeters 1 Frequency Total Mean length Standard deviation 112.5 113.5 1114.5 115.5 116.5 117. 118. 119. 50. 51. S20 53. St. 55. 56. 57. 58. S9. 60. 61. 62. 63. 611. 65. 66. 67. 68. \nmmmmmmmmmmmmmmmmmmmmm NOI—‘OHOOOHNE’l—‘Hl—‘OWE’OHOOOHOOOH |'\) O\ 56.96 16.03 l The even centimeter is the midpoint of the class interval. 115 TABLE XXVI 116 STANDARD LENGTH-FREQUENCY DISTRIBUTIONS OF LARGEMOUTH BASS, YELLGN PERCH, COMMON BLUEGILL, COMEON SUNFISH, AND THE COLMON SUNFISH X COMMON BLUEGILL HYBRID FROM WINTERGREEN LAKE, APRIL - SEPTEMBER, 1951. ALL FISH CAPTURED BY ANGLING AND TRAP NETTING. Class1 Largemouth Yellow Classl Common Common in cm. bass perch in cm. bluegill sunfish Hybrid 10.5 10.75 2 1 11.5 11.75 7 9 3 12.5 12.75 36 32 13 13.5 3 13.75 51 37 37 18.5 8 3 18.75 87 89 28 15.5 12 9 15.75 328 37 8 16.5 13 8 16.75 195 10 8 17.5 21 16 17.75 13 3 18.5 72 19 18.75 12 19.5 176 12 19.75 16 20.5 170 20 20.75 6 21.5 86 16 21.75 22.5 85 12 22.75 23.5 36 b 23.75 28.5 15 3 28.75 25.5 22 25.75 26.5 27 26.75 27.5 22 27.75 28.5 28 28.75 29.5 38 29.75 30.5 36 30.75 31.5 51 31.75 32.5 81 32.75 33.5 85 33.75 38.5 29 38.75 35.5 10 35.75 36.5 10 36.75 37.5 5 37.75 Totals 1013 122 789 218 85 Mean length 28.51 19.98 16.27 18.95 18.5h Standard deviation $5.68 é2.80 é1.83 i1.26 £1.05 1 Measurements of largemouth bass and yellow perch were made using the even centimeter as the mid-point of the class interval. Measurements of the common bluegill, common sunfish, and their hybrid were made using two groups for each centimeter class and these two groups have been combined in the data above which has the .75 as the lower limit of the centimeter class. ' 117 COMPARISON OF THE STANDING CROP AND ANNUAL YIELD OF WINTERGREBN LAKE WITH OTHBR LAKES Knowledge of productivity of various bodies of water is of vital concern to fisheries biologists. Growth rate, mortality rate, density of population, and rate of exploitation of the fish of a lake are all fac- tors which influence productivity. Standing crop of fish and the yield are the two most direct measurements of productivity used by biologists. Several methods for determining the standing crop of fish in a body of water have been used. The best known of these is draining the area covered by water and recovering as many fish as possible. Other methods are by the use of poison, electric Shockers, nets, or estimation of pop- ulation by the mark and recapture method. All methods listed above are subject to error. The most accurate is draining while the one most sub- ject to sampling error is probably the mark and recapture method. See section on Estimated Fish Populations. The following data are presented with the understanding that all information is subject to probable variation and error. Although figures given for standing crops are discrete, the reader must realize the overall inaccuracy of methods of fish population estimation. Carlander (1950) and Rounsefell (1986) both have examined a large portion of the available literature on lake production and have pub— lished extensive lists and tables incorporating the data. Carlander in- cludes the method used by the numerous investigators for estimating the population, but does not give the species of fish dominating the produc- tion figures. Rounsefell reverses the situation, by excluding method— 118 ology and including type of fish present. A complete summary of this in- formation would be a valuable contribution to fisheries management. Before entering into a discussion of the standing crops and yields of warm water lakes, the reader should be cognizant that rough fish, such as carp, Cyprinus carpio, goldfish, Carrassius auratus, and buffalofish and other suckers, Catostomidae, have the ability to produce a much heavier standing crop in pounds than the game fish dealt with in the pres- ent study. This is due primarily to their ability to convert vegetation and other low forms of life into body building substances. Game fish may be generally grouped as secondary converters, or those fish that depend on higher forms of life than vegetation for their food. The broad class- ification of rough fish may also include bowfin and gar, Lepisosteidae. These two fish are included as secondary converters. In some sections of the country they are termed game fish by sportsmen, but their usual classification is that of predator. Rounsefell (1986) also includes bullheads as rough fish. For the purpose of comparing Wintergreen Lake data with data from lakes included in the papers presented by Carlander (1950) and Rounsefell (1986), bowfin and bullheads will be excluded from the estimations calculated for Wintergreen Lake. Thus the standing crop includes only "desirable size" gamefish, no rough fish, forage fish, or small sized game fish. The total estimated population in pounds per acre of "desirable size" game fish in Wintergreen Lake is 258.8 pounds. Rounsefell (1986) lists standing crop estimates from 51 lakes and ponds. He does not in- clude any lake or pond whose estimated standing crop of game fish sur- passes the figure for Wintergreen Lake. The body of water most nearly 119 approaching this figure is 0.8—acre Delta Pond, Illinois which Thompson and Bennett (1939) state had a standing crop of 238 pounds of game and pan fish per acre. Rounsefell lists 17 bodies of water whose standing crop exceeds that of Wintergreen Lake, but 11 of them include carp and all of them include rough fish. Carlander (1950) lists the standing crop of fish in pounds per acre in 301 natural ponds and lakes. His data list 163 bodies of water which have a higher standing crop. He cites references for his data, but the writer did not investigate to find if all estimates listed above Wintergreen Lake's included rough fish. It is probable that a very great percentage of them did include species other than game fish. It is possible that'fiintergreen Lake possesses the highest standing crop of “desirable size" fish for any natural lake of comparable size. Probably the artificially fertilized, properly managed, man-made ponds of the South exceed this figure. ‘Wintergreen Lake is natural in all re- spects except that it annually receives abnormally large amounts of natural fertilizer from droppings of waterfowl present during their south- ward migration. Fishing pressure is lighter on Wintergreen Lake than it is on most other lakes with a high population of game fish. According to the theories of modern fishery biologists, this would tend to cause a de-. gree of stunting in fish of the lake. The length—frequency data do not seem to agree with this supposition until the fish have reached a large size. Apparently conditions are excellent for rapid growth of young fish into the "desirable size" classification and then the effect of competi- tion asserts itself and growth rate drops suddenly. Perhaps the natural 120 fertilization of this lake is one prominent reason why the estimated standing crop of game fishes may be the highest so far recorded for a natural lake . The total annual yield of fish taken by angling from Wintergreen Lake lends itself to a more accurate estimation than standing crop. Dur— ing 1951 there were approximately 575.8 pounds of fish removed by ang- ling. This is 18.6 pounds per acre. If bullheads and bowfin are ex- cluded from these figures, the total annual yield of game fish removed by angling in 1951 was about 553.6 pounds, or 18.1 pounds per acre. The total yield of fish removed by all methods during the year of this ex- periment was 827.0 pounds, or 21.0 pounds per acre. The above data result in an approximate exploitation rate by all methods of 8.0 percent and by angling alone of 5.8 percent. The annual yield varies tremendously. Ice fishing in the winter of 1989 and 1950 yielded a total of about 600 pounds of fish. How many additional pounds of fish were removed during the summer is unknown. Exploitation rates cannot be calculated because it is not known if the various species were present in past years in the same numbers that they are at present. When the 1951 yield of fish caught by angling ianintergreen Lake, 18.6 pounds per acre, is compared to data presented by Carlander (1950) and Rounsefell (1986), it is found that the harvest of fish is not out— standing. The figure from the lake is close to the average presented by these men. It would be an interesting experiment to allow increased fishing pressure on the lake. This would probably result in a much heavier yield without seriously depleting the large population already present. 121 S U L’T‘h’iAELY From April 21 to September 16, 1951, 3,928 fish were captured in Wintergreen Lake by angling and trap netting. Angling was a superior method of capturing largemouth bass, while netting was more success- ful for all other species present. There was a high mortality of fish in the trap nets. Condition factor of fish removed from the nets was significantly lower than the condition factor of fish captured by angling. Mortality was con— sidered to be caused by a combination of oxygen deficiency, net- caused abrasions, lowered physical vitality, and fungus infections. The lake was divided into quarters by imaginary lines. Fish captured in each quarter were given a distinctive marking by removal of the appropriate fin. Fish captured by angling were marked by cutting the soft—rays of the dorsal fin and were released at the point of capture. Soft-rays of the dorsal fin were not cut on fish captured by netting. Netted fish were released at a central station. Results of a statistical analysis of movements of largemouth bass suggested that this species exhibits a territorial tendency in this lake. Similar tests indicated that common bluegills and yellow bullheads distributed themselves randomly from the central release station and did not exhibit a statistically significant homing be- havior. Recaptures of other species were insufficient to yield sat— isfactory movement patterns. Comparison of the above data with similar investigations by Cooper (1951) on two other lakes showed that there were generally 9. 10. 122 similar behavior patterns of the fish with respect to redistribution after release. Populations were estimated by the mark and recapture method, using the formulae of Schnabel (1938) and Schumacher and Eschmeyer (l9h3). Final figures were based on the average of the estimates derived by both methods. Confidence limits were applied to the former method and limits of one standard error to the latter. Ex- planation of the methods and sources of error were presented. Population estimates were based on fish considered to be of a "desirable size" for the angler to catch and to use as food. Estimates of the population of "desirable size" game and pan fish, followed by their mean standard length in centimeters and _ weight in grams were: Common bluegill, 13,0h6 (16.28 and 203.h); largemouth bass, 2,616 (2h.50 and 327.h); common sunfish, 3,267 (lh.93 and l7h.2); yellow perch, 2,213 (19.9h and 150.1); and com- mon sunfish X common bluegill hybrid, 712 (lh.60 and 176.9). Popu— lation estimates of yellow bullheads and bowfin followed by mean total length in centimeters and weight in grams were: Yellow bull- head, 16? (32.116 and 521.3) and bowfin, 116 (56.90 and 1611.3). The estimated standing crop of "desirable size" fish present l0,358.2 pounds, or 263.5 pounds per acre. By subtracting the weight of the standing crop of yellow bullheads and bowfin the total of game and pan fishes alone was 25h.h pounds per acre. This latter figure is heavier than any standing crop of game and pan fishes listed by Rounsefell (19h6) or Carlander (1950) for a natural lake. The total annual yield for 1951 by all methods was 827.0 pounds, ll. 123 or 21.0 pounds per acre, an exploitation rate of 8.0 percent. Ang- ling alone removed 575.8 pounds, or 1h.6 pounds per acre, an exploi- tation rate of 5.h percent. The length—frequency distributions showed that h9.8 percent of the largemouth bass were between 8.7 and 10.6 inches total length and 69.3 percent of the common bluegills were between 7.6 and 8.6 inches total length. 12h LITERATURE CITED Ball, Robert C. l9hh. A tagging experiment on the fish population of Third Sister Lake, Michigan. Trans. Amer. Fish. Soc. 7h: 360-369. Birge, E. A. l90h. The thermocline and its biological significance. Trans. Am. Micro SOC. 25: 5-330 Brower, Alfred D. 1952. Ms., Fisheries andeildlife Dept., Mich. State Coll., East Lansing, Michigan. Carlander, Kenneth D. 1950. Handbook of Freshwater Fishery Biology. "William C. Brown Co., Dubuque, Iowa. v-281. Clopper, C. J., and E. S. Pearson l93h. The use of confidence or fiducial limits applied to the case of the binomial. Biometrika 26: hOh-hl3. Cooper, Gerald P. 1935a. Age and growth of three species of game fishes in Wintergreen Lake on the W. K. KellOgg Bird Sanctuary, Kalamazoo County, Michigan. Mich. Dept. Conserv., Instit. Fish. Res., Unpub. Rept. #280: 3 typed pages. 1935b. The fish fauna of Wintergreen lake on the Kellogg Bird Sanc- tuary, Kalamazoo County, hichigan. Mich. Dept. Conserv., Instit. Fish. Res., Unpub. Rept. #289: 25 typed pages. 1936a. Studies on the fish fauna of Wintergreen Lake, May 8 and 9, 1936. Mich. Dept. Conserv., Instit. Fish. Res., Unpub. Rept. #366: 6 typed pages. 1936b. Fisheries investigations on'Wintergreen Lake. Mich. Dept. Con- serv., Instit. Fish. Res., Unpub. Rept. #366-A: 2 typed pages. Estimating fish populations in Michigan Lakes. Mich. Dept. Conserv., Instit. Fish. Res., Rept. #1298: 21 typed pages. In press for the Trans. Amer. Fish. Soc. 81. '1551. 125 Dixon, Wilfrid J., and Frank J. Massey, Jr. 1951. Introduction to Statistical Analysis. MoGraw Book Company, Inc., New York, N. Y. x-370. Eschmeyer, R. W. l9h2. The catch, abundance, and migration of game fishes in Norris Reservoir, Tennessee, l9hO. Jour. Tenn. Acad. Sci. 12(1): 90'1114 o Fetterolf, Carlos M., and Allan Hirsch 1951. Plankton counts fromeintergreen Lake, Kellogg Bird Sanctuary, Kalamazoo County, Michigan. Michigan State College, East Lansing, Michigan. Unpub. Rept.: 12 typed pages. Foerster, R. E. 1935. The occurrence of unauthentic marked salmon. Biol. Board Canada, Progress Repts.(Pacific), 25: 18-20. Fredin, Reynold A. 1950. Fish population estimates in small ponds using the marking and recovery technique. Iowa State Coll. Jour. Sci. 2h(3): 363-38h. Funk, John l9h2. The food of bluegills, perch, and pumpkinseeds from'Winter— green Lake, Michigan, for 1935-1938. Mich. Dept. Conserv., Instit. Fish. Res., Unpub. Rept. #790: 20 typed pages. Hansen, Donald F. l9hh. Rate of escape of fishes from hoopnets. Trans. Ill. State Hubbs, Carl L., and Karl F. Lagler l9h9. Fishes of the Great Lakes Region. Cranbrook Institute of Science, Bloomfield Hills, Michigan. xi-l86. Manges, Daniel E. 1950. Fish tagging studies in TVA storage reservoirs, l9h7-l9h9. Jour. Tenn. Acad. Sci. 15(2): l26-1h0. Martin, G. w. —--— A modified method of making plankton counts. Iowa State Col— lege, Ames, Iowa. Unpub. Rept.: h typed pages. Petersen, C. G. J. 1896. The yearling immigration of young plaice into the Limfjord from the German Sea, etc. Rept. Danish Biol. Sta. for 1895. b 3 l—ha o 126 Ricker, William E. 1937. The concept of confidence or fiducial limits applied to the Poisson frequency distribution. J. Amer. Statistical Assn. 32: 3h9‘3560 l9h2. Creel census, population estimates and rate of exploitation of game fish in Shoe Lake, Indiana. Invest. Ind. Lakes and Streams 2(12): 215-253. l9h8. Methods of estimating vital statistics of fish populations. Ind. Univ. Pub., Bloomington, Ind., Sci. Series #15: 1-101. Rodeheffer, Immanuel A. 1939. Experiments in the use of brush shelters by fish in Michigan Lakes. Pap. Mich. Acad. Sci., Arts, and Lett. 2h(II): 183-193. . O O O O O O #9,- l9hO. The use of brush shelters by fish in Douglas Lake, Michigan. Pap. Mich. Acad. Sci., Arts, and Lett. 25: 357—366. l9hl. The movements of marked fish in Douglas Lake, Michigan. Pap. Mich. Acad. Sci., Arts, and Lett. 26: 265-280. Rounsefell, G. A. l9h6. Fish production in lakes as a guide for estimating production in proposed reservoirs. Copeia l9h6(l): 29—h0. Schnabel, Zoe E. 1938. Estimation of the total fish population of a lake. Amer. Math. Monthly, hS(6): 3h8-352. Schumacher, F. X., and R. W. Eschmeyer l9h2. The recapture and distribution of tagged bass in Norris Reser- voir, Tennessee. Jour. Tenn. Acad. Sci. 17(3): 253-268. 0 O O O O O O O , and O O O O O O O O l9h3. The estimate of fish populations in lakes and ponds. Jour. Tenn. Acad. Sci. 18(3): 228-2h9. Scott, I. D. 1921. Inland Lakes of Michigan. Mich. Geol. and Biol. Sur. Pub. #30, Geol. Series 25. ‘Wynkoop Hallenbeck Crawford Co., State Printers, Lansing, Mich. xxi-383. 127 Shetter, David S. 1936. Results from tagging Operations on Wintergreen Lake, Kellogg Bird Sanctuary, Kalamazoo County, Michigan. Mich. Dept. Con- serv., Instit. Fish. Res., Unpub. Rept. #305: 7 typed pages. Simpson, George G., and Anne Roe 1939. Quantitative Zoology. McGraw-Hill Book Co., New York, N. Y. XV’ii-h 11‘, o . Snedecor, George W. 1950. Statistical Methods. Iowa State Coll. Press, Ames, Iowa. Vii-’48; o Staebler, Arthur E. l9h8-51. Annual Reports of the Kellogg Bird Sanctuary, Hickory Corners, Michigan. Unpublished Ms. Thompson, David H., and George W. Bennett 1939. Fish management in small artificial lakes. Trans. N. Amer. 'Wildlife Conf. h: 311-317. Welch, Paul S. 1935. Limnology. McGraw-Hill Book Co., New York, N. Y. xiv-h71. HICHIGQN STQTE UNIV. LIBRQRIES Hlllll 1 312931076 4913