A STUDY OF THE FISH PRODUCTION OF A NATURAL FARM POND Thesis for the Degree of M. S. MICHlGAN STATE COLLEGE Raymond J Bullet 1944 THESIS r‘f‘g’ ;..x L“ ‘9: has ‘1. ggfiti an?“ H #119 “MP“ 0F BVV" ‘.' va‘fi—fir . As‘m'm—fi‘ \ s. 3 ' 'Em This is to certify that the thesis entitled A Study Of The Fish Production 0! A natural l'arm Pond presented by Raymond J. Buller has been accepted towards fulfihnent of the requirements for H. 3. degree in 29919:: Major. professor Date Hay IGLMLSHng, :1.) if) H] (.3 rj +4 0 "*1 *3 E3 @ H ('2 r14 "1 13"""'C"‘ T“? OF A NATUgfll FAPM tw~~ 4..\J. by Revncnd J. Egller A THEE 3 Submitted to the Graduate School of Michigan Ste 3 Colle; e of Agriculture and Aoolied Science in oartial fulfilment of the quairemente for the degree of UAQTER CF SCIENCE Dcoarteent of Zoology The author miehee to exnreee his deeneet eonrecietion to Dr. P. I. Tack for ccuneel and guidance during the course of this etudv and in the nreoerafion of the manuscrint. Sincere thanks are ertendefl to Mr. Leo Klever end Mr. Henry Predmore Jr. of the Denartment of Zoology for information and helntul succeeticne which thev have offered. The writer is indebted to Dr. H. T. Darlinqtcn of the Denertment of Botenv ior aid in identifying some of the aquatic vegetation. The enlendid cocneretion of Mr. Harold Church, owner, and Mr. Arnold Tomlineon, manager of the farm lend on which Tihert Ieke occurs, is greatly eonrecinted. Th, writer ertende his thanks and enorecistion to all others who have given aid and encouragement in this under— taking. Page kl IflterJCt13n.. ----- 0.00.00.00.00. ........ 000000.000. Physical Survey Location .. ..... . ............ .. ................ Area . ............. . ...... ...................... Classification ...... ........ ................... “raiiuage ... ...... . ......... ... .................. Denth .......................................... Bottom tynes ................................... Turbidity ...................................... \} 0.) U1 sb OJ Cr} ()3 OJ CheiniC'al Sul‘v’ey . O O O ....... O O I C I O O I O C O O O O C C O O . O O O O . O . Biological Survey Vegetation . .......... . ........ ................. 10 Food of fishes ................................. 12 17181188 0 to no. ...... o a no. 0 o o loo 0 ........ g. g 0.. o. 16 Growth rote studies ............................ 23 Turtles 0.. 0.. o 00000000000000 o... ooooo o o. O. 000.. 38 Management Suggestions ........... ........ ........... 38 Summary ............ .......... ... ..... ....... ..... ... 48 L iterature cited .... ................... ............. 45 m “V’q'ru-d ., . 3 Am D J '7‘ . J R“ l 4” H in . '. [3:91. ."euwmz l“; . l‘ Fin," "M .7) ? " KN a..- .. I g i. Q“. ‘r m ‘- “3”,? ‘u. F'n mi.» «U ”i“. K. Irma-1' ‘_ . A A. V. ~,--.:' .' Y t v ‘ i‘ Slams 71 a ‘ W3 I. ’ m "Inna/m Q ‘2“? "A STUDV OF THE FISH PPODUCTTON OF A NQTUPAL FAPV FCJD." INTRODUCTICN This naoer nresents the results of a fisheries investi- gation of Tihart Lake conducted by the writer, and includes data gathered over a neriod of eight months (July 1, 1943 to March 1, 1944). The greater cart of the field work was carried on during the first three months. The tynes of field work carried on during this neriod were: the collection of fish semeles; taking of scale samnles, as well as measure— ments from the cantured fish; manning the bond; and oortions of the chemical and biological surveys. It should not be necessary to remark on the ouroose of a fisheries investigation, but one has to talk with but a few snortsmen to realize a clear statement of oureose is justified. A greater interest in scientific investigations is being shown by anglers because of a realization that such work may hold the key to better fishing. Many fishermen are interested in learning how their snort may be imoroved. How- ever, these reoorts are scattered and it is almost imeossible for the average reader to secure a knowledge of nresentations which give a clear understanding to the biology of a fish? eries survey. The nrincinal objective of the work here renorted was a study of the actual fish nroduction of Tihart Lake with "an eye towards" increasing this yield in future years through a nroaosed management alan. A secondary obiective was concern of renorts that a large care nooulation inhabited the bond. These renorts were of interest as the Zooloqy and Home .‘ Economics Denartments of Michigan State College were exocri— menting with the edible qualities of this soecies. Permission was obtained to remove these fishes from the bond for such exnerimental nurnoses. The results of the findings concerning care of Tihart Lake may be found under that branch of the biological survey of the bond dealing with fishes. THE INVESTIGATIONS AND PERSONNEL The actual field onerations were conducted by the writer with the assistance of Mr. Lee Klever. The field work was done largely from July 1 to October 30, 1943. Mr. George Wallace and Mr. Hemmer Sessions aided in the work from time to time during the entire period. The manning of the oond was sunerintended by the writer with assistance of the three above-mentioned men and the ore— nared base man was redrawn by the writer. The outline of this man, which is to be found on the inside of the back cover of this volume, is based entirely on triangulation noints at thirty shore stations from a.common base line. Bottom contours, distribution of vegetation beds, and bot- tom tynes are from readings at additional stations. PHYSICAL SURVEY OF TIHART LAKE Location. Tihart Lake, in Ingham County, is situated in Meridian Township (T. 4 N., R. l W., Sec. 14) about five miles north- east of East Lansing on a farm owned by Mr. Harold Church, and managed by Mr. Tomlinson. The nond is elongate in a north and south direction and is flanked on the west and north by rolling farm land. The send is accessible only through the farm yard and lane of the farm on which it OCCUI'S . Area. The area of Tihart Lake, 8.38 acres, was obtained from the nreoared base man by the use of a olanimeter. The marshy nature of the shoreline made manning very difficult and because of this the actual area may be slightly greater than the figure given above. The given area is that of the onen water only, irresoective of flooded marshy nortions which occur at several ooints about the border of the nond. Classification. There has been a great deal of controversy as to the definition of a send as differing from a lake. Forel (1892) defines a lake as a standing body of water occuoing a basin and lacking continuity with the sea and defines a oond as a lake of slight deoth. Welch (1935) defines a nond as a small, shallow standing body of water in which quiet water and extensive occunancy by higher aquatic nlants are common characteristics. He refers to all larger standing bodies of water as lakes. By aoolying the definitions of both Forel and Welch to Tihart Lake plus the data which follows, it can be readily understood why the writer has chosen to classify it as a natural nond. A natural nond being one that is formed in a normal catch basin as comoared to an artifici- ally imoounded oond. By anolying a classifiCation develoned by Forel and later modified by Whinole oertaining to temnerature, Tihart Lake may best be classified as a temoerate nond of the third order. It is of the temnerate tyne because the surface tem— oeratures vary above and below 40 C, and it is a third order nond because the temnerature of the bottom water is very similar to that of the surface water and circulation is continuous exceot when covered with ice. Using still another classification, on the basis of nroductivity, Tihart Lake falls in the dystronhic tyne. This classification is based on olankton communities, bottom fauna, dissolved oxygen supnly, bottom deoosits, and bio- logical productivity. Tihart Lake lies in a shallow basin almost surrounded by a marshy area. This general form is also characteristic.l of the dystronhic tyne. Drainage. Drainage waters entering Tihart Lake are limited to those coming from a marshy area extending several miles east and north of the oond, served by the inlet which emoties into the send near the center of the south-east shore. Throughout the normal seasons the flow remains regular and carries very little sediment into the oond. During the rainy seasons however, this normal flow and carrying capacity is greatly increased resulting in a delta of sand found at the mouth of the inlet. Very little run—off water from the surrounding higher ground finds its way into the nond. The surrounding soil is a mixture of Sand, silt, clay and muck, much of which holds water rather well and retards run-off where it might occur. In the nresence of a oermanent outlet, fluctuations in water level are not noticeable. Anoroximately two miles below the pond the outlet joins the outlet of Lake Lansing which is tributary to the Red Cedar River. This arrangement nlaoes Tihart Lake in the Grand River drainage system. Death. The maximum death of the nond is thirteen feet. The denth measurements were secured in the following manner: ten boat trios were taken across the nond at right angles to its long axis, and one trip was made along the long axis. A deoth measurement was secured every five oar strokes on all these tries, using a cone-shamed sounding weight. It is entirely nossible, however, to have missed any deen holes that might occur in the nond using this method, but the characteristics of the bottom make this imnrobable. The bottom contours and slones from the shore to the deenest narts of Tihart Lake are irregular. The five-foot contour was found in several instances in close oroximity to the shoreline. It is only in the north—east end of the send that the bottom alone is gradual. The ten-foot contour was found to have aonroximately the same relationshin to the five- foot contour as the five—foot contour has to the shoreline. The alone from the ten—foot denth to the deenest narts of the nond is very slight. This arrangement gives Tihart lake 8 saucer-shaned basin with the greatest bottom area covered by ten or more feet of water. Bottom Tynes. Three distinct bottom tynes were found, namely: fibrous neat, marl, and sand. Sand covers only a very small area, at the noint where the inlet enters the nond. Here a delta of alluvial sand has been denosited after heavy rains, have swollen the inlet and increased its carrying caoacity. The sand extends some 20 to 30 feet into the nond and is hard enough to bear the weight of a nerson, unlike the rest of the shoreline which is fibrous neat and will not sunnort a human. Fibrous neat comorises the bottom of all the shoreline, save that area described above. Along the south-east and north-west shores it extends, in some instances, 50 to 75 feet before merging into the marl which is the characteristic bottom tyne for the nond. Along the north-west shore the fibrous neat extends but a short distance, 15 to 25 feet, into the oond before giving away to the marl bottom. Only a narrow fringe of fibrous neat was found along the north shore. Here the marl extends to within 5 to 10 feet of the shoreline. Along stretches of the east and west shore continuous with the south end of the nond, fibrous neat sunnorts continuous beds of emergent snatterdock. Three more or less distinct habitats are thus nresented, each determined by the under- lying bottom. Turbidity. The color of the water in Tihart Lake is brown, char— acteristic of its bog and marshy surroundings. Turbidity runs high: a Secchi disc reading on July 10, 1943, was 2 feet 4 inches. Readings taken at ten-day intervals, July 20 and August 1, 1943, were 3 feet 3 inches and 4 feet 2 inches, resnectively. The high turbidity on July 10 is thought to have been caused by the great numbers of nlank- ters and algae nresent on that date. As the summer pro- gressed these nlants and animals began to die and the water became less turbid. There were times during this neriod of high turbidity that the nond was covered with a thin bluish-green bloom, the clankton and algae being so numerous. The effect of the bloom unon fishes was not noticeable. CHEMICAL SURVEY OF TIHART LAKE Table 1 lists the chemical analyses of water samnles taken from Tihart Lake during the winter of 1944. The methods used were those outlined in Standard Methods for the Examination of Water and Sewage (1938). The Winkler method was used for the determination of the oarts per million of dissolved oxygen. TABLE 1 CHEmlCAL CHARACTERISTICS OF TIHART LAKE a '” g z c: m 9. Ha Es a a... E i fig :1 g 64 x 2 an F1 fl m :3 z m g c B E§ E B F‘ ‘9 m Q B a Q <3 H 4: <1: in C.) (1': .4 E7). O 0 EU) 5’ £73 Caz gig a o m m <3 ~ g :r A E $3 a 3 EE d: E < [:3 E—‘U Hg; 0 ..a Q [:1 Q C) .* ___ 1 1/25/44 0 S 4 9.9 11 210 13-B** 4.5 -—— 4.0 22 gen 2 2/17/44 0-8 3 7.4 12 8 290 IO-B 5 7.2 5.8 14 336 - '1 r? 3 2/17/44 0 S “.5 .67 15 12 250 7—8 5 7.0 7.2 80 325 4' Surface readings ** Bottom readings It may be noted from reviewing the data in Table 1 that there is a considerable oxygen deoletion at the bot- tom. This is to be exnected, owing to the organic nature of the bottom denosits. This is not a limiting factor, however, since the nond is relatively shallow. A shallow nond such as Tihart Lake is subject to winter anaerobiosis and an accomnanying fish-kill should the ice cover and heavy snows oersist. The last few winters have been moder- ate and there are no renorts of a winter kill for Tihart Lake. The free carbon dioxide in Tihart Lake is high. This is natural during the winter months since the ice cover nrohibits the escane of the gas. An area of ooen water occurred at the noint where the inlet emoties into the pond throughout the winter. This may account for the difference in values of free carbon dioxide at station 2 and stations 1 and 3 as the ooen water would nermit escane of some of the gas. Station 2, t may be noted from the man, was near and almost in line with the inlet. The high results for the bottom readings are attributed to the accumulation and decomnosition of organic matter. The waters of Tihart Lake are only slightly alkaline, having an average nH value near 7.3. The methyl orange alkalinity or bound carbon dioxide is high as is the case of most of the waters of this region. The chemical characteristics of Tihart Lake are similar to those of Burke, Park and Rose Lakes and Lake Lansing (Boelofs 1941). 10 BIOLOGICAL SUQVEY CF TIHAFT LAKE Vegetation. The higher aquatic flora are reoresented by both emer- gent and submergent nlants. The yellow water lily, soatter- dock, or cow lily (Nunhar advena Ait.) is by far the most common and nrominent snecies oresent. Only one other snecies of emergent or surface vegetation was found. This nlant was the lesser duckweed (Lemna minor L.) which was not discovered in the nond until late in the season (Oct. 1943). The distribution and extent to which the yellow water lily inhabits the send is demonstrated on the man. The beds of emergent vegetation shown in this man are entirely com- posed of soatterdcck. Swingle and Smith (1942) consider nond weeds to be noxious because they grow so rabidly that they soon fill the bond. They are also objectionable be- cause they nrotect the smaller fish from larger ones so well that the nond may soon become overcrowded and the fish stunted. Smith and Swingle (1940 and 1941) have develoned methods of controlling oond weeds by mechanical means and by the use of fertilizers. Lagler and Ricker (1948) consider the yellow water lily to be of nositive value in providing shade to cool the water, in harboring insects immortant as fish food, and in 0T0- vidinq fish shelter. The soatterdock beds in Tihart Lake have not reached the extent at which they have deleterious effects uoon the nond and are believed to be of positive value to it. In sunoort of this belief, bluegills and 31 largemouth base were observed lying in the shade made by the leaves of this nlant during the hot, clear summer days. Numerous schools of young fishes were observed among the beds of yellow water lily, and many bluegill and largemouth bass fingerlings were taken with a scan net from such beds. The submergent vegetation consists of one green algae (Soirogyra sn.), water weed (Anacharis canadensis Michx.), water buttercuo (Ranunuculus aquatilis L.), and coontail (Ceratonhyllum demersum L.). Of these four submergents, the algae and coontail are by far the most common. Cocntail was found almost as extensively in the bond as scatterdock. It grows along the shore in water to a death of five feet. None of the submergent vegetation nenetrates beyond the five foot deoth since the water is too turbid for such growth to exist. An imnortant semi-aquatic slant of the shoreline is the water willow (Decodon verticillatus (L.) Ell). This nor- L mally terrestrial snecies forms a fringe up to ten feet in width for three—quarters of the shoreline. The water willow is sunnorted by the fibrous neat and is accompanying the en- croaching bog mat. This nlaces the roots and stems of this nlant in water us to a foot in death. Just as the extensive beds of soatterdock afford fish shelter so does the water willow. Many of the younger fishes (bluegill) and Smaller fishes (stickle back and mudminnow) were found using this feature of the nond as a shelter and haven from the larger nredacious fishes. It is also nossible that these submerged areas of water willow may be utilized for soawning during the snawning seasons of such snecies as the care, nike, and even bass and bluegill. Food of Fishes. Bottom samoles taken with an Ekman-Eirge (size: 6" x S") dredge were analyzed in order to determine the kinds and amount of available fish food organisms. These, six in all, include collections taken from all of the bottom tynes of the send (sand, fibrous neat and marl) at varying deaths. The stations at which the samnles were taken are indicated on the man. The samnles collected by the use of the dredge were transferred to large glass jars and brought into the labora- tory. Here the animal life was nicked out of each and ore— served in 10% formalin solution and later identified. The following discussion lists the organisms found in-the samnles by station, the bottom tyne, and the deoth at which it was taken. Station #1. Bottom tyoe-—sand; denth-Labout 10 inches. The organisms found in this sample were Ostracoda; Coneooda; genera Cathocamotus and Cyclone; the scud (Hyalella), order Amnhiooda; and larvae of the genus Chironomus, order Diotera. The Ostracoda, Amohiooda, and Chironomids were quite common. Single snecimens of the two genera of Conenods were identi- fied from the Bamole. Station #3. Bottom tyne—~marl; denth--lO feet. Organisms identified in this samole were Ostracoda and larvae of the order Diotera, genera Corethra and Chironomus. All of these animals were abundant in the collection. The Chirono- mids were the large red so-called "blood worms." Station #3. Bottom tyne--fibrous neat; denth--about 2 feet. Ostracoda; the two genera of Cooeooda, Canthocamntus and Cyclone, and the Amnhiood, Hyalella, were common in this samnle. A single saecimen of the water mite, Hydracarina, as well as a nymnh of the damsel fly, genus Anomalagrion were identified. Chironomid larvae were very abundant. Nymohs of the order Ephemerontera, genus Caenis, were common and one leech, class Hirudinea, was found in the samole. Station #4. Bottom tyoe—-fibrous peat; denth--l2 inches. This collection taken from the same tyne of habitat as No. 3 was found to exhibit the greatest variety of insect life. Ostracoda and the Amohiood, Hyalella, were relatively common. Leeches, class Hirudinea, were found as in the nreceding samnle. Chironomid larvae and the May fly nymoh, Caenis, were soarsely renresented. Nymnhs of the damsel fly, genus Anomalagrion and the two genera Tetragoneuria and Somatoch- lore of dragon flies were also identified from the samnle. Station #5. Bottom tyne--marl; death-~13 feet. But three forms of animal life were identified from this collection. Ostracoda and the nhantom midge larvae, Core— thra, were abundant. Chironomid larvae, the "blood worm", were common . 14 Station #6. Bottom tyne-~fibrous neat; denth-—18 inches. This samnle yielded but three forms of animal life as did the nreceding collection. The "blood worm" larvae, Chironomus, was very abundant. Ostracoda were common and a single nymnh of the May fly, Caenis, was identified. The following list of aquatic insects, adults, nymnhs, and larvae was secured through the identification of insects collected at odd times throughout the nhvsioal and chemical surveys. Some were collected with the soap net while others were taken at the time the aquatic vegetation was collected. The list is as follows: Order Odonata--—nymnhs Suborder Zygontera~——damsel flies Family Coenagrionidae Genus Argia Suborder Anisontera-——dragon flies Family Libellulidae Genus Tetragoneuria " Svmnetrum " Mesothemis " Somatochlora " Plathemis Order Hemintera—--adults Family Corixidae——-Water-Boatman " Neoidae--—Water Scornion " Belostomatidae-——Giant Water Bug Order Coleontera—--adu1ts and larvae Family Dytiscidae--—Predacious Diving-Beetle Table 11 lists the animal life nhylogenetically and the numbers of each taken at the six stations in the nond as well as the aquatic insects collected at odd times. Microsconic nlants (nhytoolankton) occurred in quantity in samnles taken on July 15, 1943. Cyanonhyceae, blue-green algae, genus Nostoc was the dominant form. Another blue- green form was the genus Ashanocansa. The most abundant 15 TABLE ll Phylogenetic List and Numbers of Animal Life Collected from Tihart Lake. —.v~—-—— -_—-—. Station “Numb er -‘w- .——-m-. - -—-—._——.—. Elly—logepotjc Ilct “_____ 1 g- __:_2' 4 5 6 13/7180. Phylum Annelida . _Class Uirudinea 1 .4 w—--—---——~-- -—_. Phylum Arthronoda Class Crustacea __§ubclass_qstracoda _~_§:_‘gx** x x ‘__zx x _ Subclass Conenoda ...fiaaaagahthqqa mat-us ..1 1 ..-- .. - ..GantiL01c.lon 8 .. 2 - 1 Subclass Malacostraca Order Amohiooda __“ Ge_n1s _{yalella 2 8 11 Class Insecta Order Enhemerontera Cenus Qaenis lO 1 1 Order Odonata Sucorder Zygontera Family Coenagri.onidae -.CQTDLS Angelagrron __ l _ Genus figyia l Suborder Anisontera Family libellulidae {gmg§_T3:ragoneuria __ 1 S_ " Somatochlora l 3 " Symmetrum l l l " ”esotheris _ " Plathgmis Order Heminter _ Family Corixidae xr_ Tarilyl Qidae 1 Family Belostomatidae 1 Order Coleontera. . Family thiscidae 5 Order Dintera Family Chironomidae Genus Cl _iro_nomu_s 8 2O 29 Family Culicidae - - Gen -LGQJLRJQL 1‘9 9 '7 1 6 Class Arachnoidea Order Hydracarina l r—k 39 ;JJ 0) * Common ** Abundant green algae, Chloronhyceae,was the genus Oedogonium. Other green algae forms common to the nond are desmids and diatoms. Microsconic animals (zoonlankton) identified from the nond were the Ostracods and Conenods named above which were taken at the time of bottom samnling. Figure 1 shows the food chain leading to the nroduction of legal-sized game fish in the nond. The key industry animals are consumed by young bluegills and crannies. These young centrarchids, nlus minnows, nrovide the nrincinal food for largemouth bass, the larger bluegills and black crannies and the northern oike. Another common groun of fish tyni- cally feeds directly unon bottom foods. Its members are the white sucker and golden redhorse. Fishes. The fishes of Tihart lake were cantured with nets and by hook and line fishing. Three tynes of nets were used, namely: fyke, gill, and scan nets. Two 2%—inch stretched (la—inch square) mesh fyke nets were nlaced in the nond July 7, 1943. These were set narallel with the shoreline to take fishes in their shoreward movements. The fyke net sets were changed each week as the catch tended to become less after the nets had remained in the same area for a neriod of four or five days. Occasionally one of the nets was nlacsd in deen water, but this oractice was abandoned as the catch was not large enough to warrant it. A fifty-foot leader of 4-inch stretched (2-inch bar) mesh was added to one of the fyke nets in hones of increasing 0) 17 ‘.---_---- SECONDARY ARNIV as (Pnscwonous) NORTHER PIKE. LARBEHOUTH BASS, AND BLA canines. CROP-- Pam Y CARNIV £3 snows, Youu museum)?" was. LUEOILL3,AND LACK saunas. v mousrnv nun ( RBIVOREB AND scAv: cans) AQUATIC mszcrs. oruuxrou (OSTIAOODA coupon. AND AIPHIPODA). _____.l.. ___...L.___._ FORAGE'4 Pnoouczns (PLANT!) YILLow mm! LILY, OOONTAIL, AND one" ALGAE (SPIROOYRA sp.) Pavropunxron (BLUE-GREEN AND a nu ALGAE). f""-"'" DussoLveo NUTRIENTS. Dnmrus. SOIL. SAND. FIBROUS FEAT. AND HARL. FIG.I. Fooo CHAIN RELATIONSHIP FOUND IN TIHART LAKE. 18 the catch. The net was set with the leader running out from shore with the fyke net at the outer end. This arrangement increased the catch of turtles in the net but had very little effect on increasing the fish catch. Gill nets varying from 35—5—1nch stretched (1 3/4—35— inch square) mesh were nlaced in the nond for several days in August, 1943 and again for a two—Week neriod in October, 1943. These nets were set both narallel with the shore and running out into the nond from shore. Very little difference was noted in the numbers of fish cantured in relation to the net set. During the two-week period of October that gill nets were run in the nond, two 100 feet gill nets were tied end to end making a net ZOO—feet in length. This net when set stretched anoroximately halfway the distance across the nond. Even this arrangement failed to increase the fish catch any annreciable amount. It was useful, however, in obtaining some of the larger suckers inhabiting the nond. The catch taken bv hook and line fishing nroved to be very small. One soecies, however, was taken by this method that was not taken in the nets. There are no creel census resorts available for the nond. It is the author's belief that such resorts would siow a very low catch as comnared to the time fished. A scan net, a shallow dip net with a long handle, was used from the boat and shore to take small fish along the shoreline. Many bluegill and bass fingerlinss were taken in this manner as well as several other shore and mud- dwellina snecies. 19 The standard and total lengths in millimeters were recorded for all the fishes centured in the nets and by hook and line fishing excent the bullheads. Only a record of the numbers of this soccies cantured was recorded. Scale ssmoles were taken from all the game fishes captured. These were removed from the left side of the fish mid-way between the dorsal fin and lateral line. The scales were olaced in snecially prepared enveIOpes bearing the measure- ments of the resoective fish. Those fish taken alive in the nets were returned to the nond after the anal fin had been clinned. The clinning of the anal fin was done to serve as a check for fishes recantured in the nets. The bullhead was the only snecies recaotured in the nets. The right nelvic fin was clinsed on those that were taken a second time. The netting of fish was discontinued after a snecies list had been comniled for the nond and scale samoles and measurements had been taken and recorded for a total of one hundred and sixty-six soecimens. Table 111 nresents the snecies, manner of canture and total numbers of each taken during the three and one-half months of netting oneration in Tihert Lake. 20 TABLE 111 Method of Gesture Snecies Fyke Gill Scan Hook and Total net net net line Bowfin, dosfish x 1 Golden redhorse x 2 Common sucker x x 30 Carn* Yellow bullhead x x 54 Tadoole madtom** x Mud minnow** x Northern Dike x x 10 Yellow nerch x Johnny darter** x Larsemouth bass x x x 13 Warmouth bass x x 3 Sunfish x 4 Bluegill x x x 54 Black crannie x 45 Brook stickleback** x * This snecies is resorted for the nond, none were centured during the netting onerations. **“Numbers of these fishes were not recorded but included here in the scecies list for the nond. An annotated list of fishes that occur in Tihart Lake with a brief discussion of each snecies follows. Amiidae-—Bowfins 1. Amie calva Linnaeus. Bowfin, dogfish. But one snecimen was cantured in a fyke net. A predatory species which is considered rare to the nond. Catcstomidae—-Suckers 8. Catostomus commersonnii commersonnii (Lacenede). Common sucker. Figures from the netting results show this snecies to be a common one of the nond. The snecies is of major imnortance in ecological relations with other snecies both as a food sunnly and as a comaetitor. Pl 3. Moxostoma erythrurum (Pafinesque). Golden redhorse. Two snecimens were taken in July in the fyke nets. It is not as abundant as the common sucker, but of imcortance in ecological relations with other soecies. Cyprinidae--Minnows 4. Cynrinus carnio Linnaeus. Cars, German care. Reports are that this snecies was observed snawning along the shores of the nond early in the summer. However, not a single snecimen, young or adult, was taken throughout the netting onerations. It cannot be concluded from this fact however, that earn do not inhabit the nond. Several schools of small minnows were observed in the nond at various times throughout the summer. Attemots were made to canture them for identification pursoses. None were cantured, however. These fishes are imaortant, serving as forage fishes for the larger fiShes of the pond. Ameiuridae—-Catfishes 5. Ameiurus natalis (Le Sueur). Northern yellow bull— head. This snecies is common in the nond. A survey of fishermen showed that this soecies is not sought for in angling. A total of fifty-four soecimens were cactured in the fyke nets, the anal fins of which were cliched, and returned to the nond. This is the only snecies to have been recantured in the nets. 6. Schilbecdes gyrinus (Mitchell). Tadcole madtcm. A relatively common snecies of the nond which inhabits the shallow, weedy areas. Of little value as a forage snecies. Umbridae--Mudminnows 7. Umbra limi (Kirtland). Mudminnow. A common forage soecies of the nond. Found to share the shallow, weedy areas with the tadoole madtom. Esocidae--Pickerels 8. Esox lucius (Linnaeus). Northern Dike. A thinly scattered member of the nond. It is an imoortant game fish and furnishes some fishing in winter as well as summer. Also imoortant as a nredatory soecies in keening the numbers of smaller fishes in check. Percidae--Perches 9.-Perca flavescens (Mitchell). Yellow nerch. Rare, but five were taken by hook and line early in the summer. Of very little value for angling. lO. Boleosoma nigrum nigrum (Rafinesque). Johnny darter. A soecies soarsely distributed in the nond inhabiting the shallow, weedy areas. Centrarchidae--Sunfishes ll. Huro salmoides (Lacenede). Largemouth bass. One of the three most imnortant snecies inhabiting the nond. Figures from the netting onerations tend to show that this snecies is not abundant in the nond. It is felt however, . that a very small oercentage of the adult bass in the nond were caotured. Many fry and fingerlings of the snecies were observed in the shallows of the nond. The soecies is im— nortant as a game fish and furnishes a great deal of angling. 18. Chaneobryttus gulosus (Cuvier). Warmouth bass. m 23 Rare to the nond. But four snecimens were taken in the gill nets in October, 1943. This fish is of little angling imnortance, the young serving as forage for the larger fishes. 13. Lenomis gibbosus (Linnaeus). Common sunfish. Another rare member of the nond. Not abundant enough to be of any angling imoortance. 14. Leoomis macrochirus macrochirus (Rafinesque). Common bluegill. The most common and abundant snecies in- habiting the nond. This fish is the one most sought for by anglers in both winter and summer fishing. 15. Pomoxis nigro-maculatus (Le Sueur). Black crannie. This fish ranks with the bluegill in abundance. It, as well as the bluegill, furnishes a great deal of fishing in both winter and summer. Gasterosteidae-—6ticklebacks 16. Eucelia inconstang (Kirtland). Brook stickleback. A common snecies dwelling in the shallow, weedy areas of the nond. Growth rate studies. This study on the age and growth of the fishes from Tihart Lake is based on 166 soecimens taken throughout the summer, fall and winter of 1943. The 166 fish were taken .with fyke nets, gill nets, scan nets and hook and line. All measurements were obtained from fresh fish in the field by means of a soecially constructed measuring board. Standard and total length measurements were recorded in millimeters on the scale envelooes containing scale samnles of the re- soective fish. 24 The scales were cleaned, mounted in a glycerine-gelatine solution, and studied in the customary manner by means of a microorojection annaratus at magnifications of 26 and 46 diameters. The micronrojection machine emoloyed in determin- ing the age of scales of fishes from Tihart Lake is construc- ted similarly to the one described by van Oosten, Deason and Jobes (1934). All growth computations were based on measure- ments made along the anterior radius of the projected images of the scales. The calculations were made on the assumotion that the bodyscale ratio remained constant at all times after the comoletion of the first annulus. The age of each fish, eynressed by Roman numerals, indicates the number of annuli found on the scales. Thus, a 111-year fish renresents one taken in its fourth year of life. I am greatly indebted to Dr. Peter Tack for valuable assistance rendered in determin- ing the ages of some of the more difficult scales. The order in which the age and growth analysis of fishes from Tihart Lake occurs is based on the angling imoortance and relative abundance of the snecies inhabiting the bond. Fish will be given only their vernacular names in what follows; a list of corresoonding scientific names is given earlier in the naoer under that section dealing with the fishes of the nond. BLUEGILLS This snecies and following fish, black crannie, are about equal in abundance. The bluegill however, is of greater imoortance and is therefore considered first. In Table 1V the fish in the samnle have been divided into age grouns and according to the year class to which they belong, with individuals of each grouo arranged by their standard length. The number of individuals in each age groun and the percentage of that number in the entire collection are shown at the bottom of the table. The column at the right gives the number of fish of each size groun. The table reveals that no fish taken were younger than 3 years or older than 9 and that age grouns 11, 111, V11, and V111 were noorly renresented. Age group V bredominated in the 8amnle, comnrising 39 oercent of the catch. The bulk (79.8 nercent) of the samole was combosed of individuals that belonged to age grouse 1V, V, and V1. TABLE 1V Frequency distribution of Tihart Lake bluegills accord- ing to standard length in millimeters, age group (Roman numerals), and year class (calendar years), with sexes com- bined. Standard _ Age groun and year class Total length in 11 111 1V V V1 V11 V111 number mm. 1941 1940 1939 193a 1937 _1938 193 94.5-104.5 l .. .. .. .. .. .. l lO4.5—1l4.5 .. .. .. .. . .. . 114.5-124.5 2 .. l . . . . 3 124.5-134.5 .. 3 2 .. .. .. .. 5 134.5-144.5 . 1 4 4 .. .. .. 9 144.5-154.5 .. 1 3 6 2 . .. 12 154.5-164.5 .. 3 8 4 3 .. l7 164.5—174.5 .. 3 3 .. .. 6 174.5-184.5 .. .L__ .. .. .. .. l 1 Number 3 5 13 21 9 8 1 54 Percentage. 5.5 9.3 24,9 aflo 18.7 as? 1.8 Table V shows the mean standard length and mean increment in standard length of bluegills of each age group for sexes combined. Figure 2 shows the growth curve of Tihart Lake bluegills. The curves of this figure are based on the mean standard lengths and the mean annual increment taken from Table V. The growth illustrated by the curve is normal until it reaches age group V11 where it sud— denly turns upward to the age group V111 mark. The exnlana- tion for this feature of the growth curve is an insufficient number of specimens of age grouo V111. In length the bulk (70.3 percent) of the sample ranged between 136 millimeters, standard length (total length 6.8 inches) and 164 millimeters, standard length (total length 8.26 inches). Figure 3 presents this data graphically. It may be noted, by reViewing Table 1V, that length is a poor index of age, since fish of the same length may belong to as many as three or four different age groups. ‘ TABLE V Mean standard length and increment in length for each year class and age group of Tihart Lake bluegills, sexes combined. Year Age Io. of Kean standard Mean total Increment class group specimens length in mm. length in in S. L.* inches. 1941 11 3 110 5.5 .. 1940 111 5 137 6.8 27 1939 IV 13 143 7.2 6 1938 V 21 154 7.7 11 1937 V1 9 169 7.9 5 1936 V11 2 168 8.1 3 _1935 V111 l 178 8.9 16 *Standard length 27 .> “405—. no Qucao.k 20 omm¢=0 ...—3080 UO< zo¢30 mulod .maoma uo< Io¢30 mun—m3 MAJ—cmaJn urtJ h¢¢=0 IP30¢O .N .OE mDOmG w0< h o n c n N _ w _ who 11" \ on \ 8. on. Illici'lf I.||..l|ll4. In!!! IIiTln CON 'WW NI HLSNB‘I OUVONVLS NVBW Fne. 3. STANDARD LENGTH FREQUENCY DISTRIBUTION or TIHART LAKE BLUEGIL L8. STANDARD LENGTH (MILLIMETERS) z T I? ~— .,.___,, - _ .... ' 1 I 1 . ' , '8 i 4 » — +7 a y— - ~ —-— "i a —- -~———————+ ; i E I t ? |5 .- _ i 1‘ -__ _- -.L. ~—~-—-—+ )“ i i- T _ _ i___.. L 1 l4 -————~—- - 9— 1~———A ~ 1 s w I 1 i ' .3 . I + I a i + .. .- was I2 *‘ * ' "‘ ‘ ““‘—"“ l | L_'— ‘ —-————1 ..-‘f‘ -4 ... - -..... ......1. --.—i 9 {m i . | i 7 f ,, A e p——-——f.s—~__f__--m¢)_ 1L w—— -.- .. 4.....— 3 —" E 1 '1— fl” " 7” _ i a : 4 ..__- A v , ---- . a 3"———-%~~ -—~— # L————-——I 4;” -—-—1 + i t l 2 -—-—-——— F a l 4 — »~-———+ »——— r— l v———»< l ._____ T H _- .4 I...“ z i I o /1 v , J / 95.54045 n5.5-:24.5 35.5444!) 155.5-l64.5 was-mus {\D (0 Table V1 shows for sexes combined the mean computed standard length at each annulus of the bluegills. The method of calculation used was the formula develoned by Fraser (192 ). The standard length at any annulus is equal to Ln: C 4- Sn(L-C) S where C is the length at the time of scale formation (20 millimeters was assumed for bluegills, black crannies and largemouth bass), Sn is the scale diameter (or radius) at any annulus, S is the scale diameter (or radius) at time of capture, and L is the length at time of capture. The number of specimens used in calculating the standard length at any annulus is indicated in the table. The calculated lengths are to be regarded as close annroximations rather than actual lengths. TABLE V1 Mean calculated standard lengths for each annulus of each year class and age group of Tihart Lake bluegills, with sexes combined. Year Age No. of Calculated standard length, in mm., class group Specimens at annulus __ 1 2 _§_ 4 5 ” 6 7 8 1941 11 3 5O 92 ... ... ... ... ... ... 1940 111 4 52 86 118 ... ... ... ... ... 1939 1V 3 51 86 118 143 ... . . ... 1938 V 3 40 67 96 128 138 ... . 1937 V1 3 36 63 92 119 137 153 ... ... 1936 V11 2 38 59 87 109 128 144 156 ... 1935 v11 1 1 36 6- a--- -.1.qa_-il.§.-_1_43_ 157....1.‘3fi_.12£i Grand averages calculated_leng§h___w___4§__ 74 _1Ci__”23 136 151 161 173 The calculated lengths indicate considerable variation in the growth of the different age grouse. For examole, age grouns V1 and Vlll reached a length of only 36 millimeters at the first annulus mark, whereas age grouo lll attained a length of 58 millimeters. Differences in rates of growth occurred also in the other age grouns. An analysis of the growth data for Tihart lake blue- gills shows that the growth of this snecies is about normal for this section of the state. The fish reach the Michigan legal limit during their fourth year of life, and when growth for that year is comoleted are about 6.8 inches long. The growth of this snecies in Tihart Lake is comoarable to the growth exhibited by Foots Pond bluegills where they achieve a length of 6.7 inches in their fourth year of life (Ricker and Lagler, 1942). BLACK CRAPPIE In Table Vll the fish in the samole have been divided into age groans and according to the year class to which they belong, with the individuals of each groun arranged by their standard length. The number of individuals in each age groun and the percentage of that number in the entire collection are shown at the bottom of the table. The column at the right gives the number of fish of each size groua. The table reveals that no fish taken were younger than 3 years or older than 8 and that age grouns 11, V1 and Vll were noorly renresented. Age grouns 1V nredominated in the samnle, comnrising 35.5 oercent of the catch. The bulk (73.8 percent) of the samnle was comnosed of individuals 31 that belonged to age grouns 111, 1V and V. TABIE V11 Frequency distribution of Tihart Lake black crannies according to standard length in millimeters, age grouo (Roman numerals), and year class (calendar years), with sexes combined. u—c. -——- —- Standard Age groun and year class Total length, in 11 111 IV V V1 V11 number mm. .éagl 194e, 1939 1938 1937 1936 lO9.5—ll9.5 3 3 . . .. .. 6 119.5-129.5 l . l 129.5-139.5 l l l39.5—149.5 .. .. .. . .. 149.5—159.5 . 1 4 1 .. .. 6 l59.5-169.5 .. l 2 l . 4 169.5-179.5 . .. 6 l .. .. 7 179.5—189.5 . 1 8 8 3 1 9 189.5-199.5 .. .. 2 4 l 1 8 199.5—209.5 . . . 2 2 809.5-819.5 .. .. .. .. .. . . 219.5-229.. .. .. . . .. .. 999.5-939.5 .. .. . . . l l Numgers_~ 3 8 16 9 6 3 45 Percentagefi~_ 6.7 17.7 35.5 “0 O 13 4 6 7 Table Vlll shows for sexes combined the mean standard length and mean increment in standard length of black crannies of each age groun. Figure 4 shows the growth curve of Tihart lake black crappies. The curves of this figure are based on the mean standard lengths and the mean annual increment taken from Table V111. The curve indicates the growth for this soecies is relatively rapid. 32 ....> u...o<._. “—0 mum—DOE to aum¢=0 ...:Omo mo< 20(m 10.... IPQZHJ ac¢oz¢=o cm’oJ .maomo ua< 10(u mo IPOZUJ o¢¢30 mummD nu_mm<¢o x0<40 mx(n_ h¢<3..—. to afl>¢=o IF30¢O ..V .0...— QDOmw mw< . w 0 ¢ n N _ O 4. \ m. 1/ N V Om \ m N v N O V 09% \ ... \ 3 N m \ 02m \ N W \\ W \\ . rl\ll\\\l OON 33 TABLE V111 Mean standard length and increment in length for each year class and age groun of Tihart Lake black crannies, sexes combined. Year Age No. of Mean Standard Mean total Increment class groun snecimens length in mm. length in in S.L.* " inches 1941 11 3 113 5.6 .. 1940 111 8 138 6.9 25 1939 IV 16 178 8.6 40 1938 V 9 182 9.1 4 1937 V1 6 198 9.6 10 ozm30mmu Ihwzud om