mam-mm This in to eerflfg that the thesis entitled r “Contributions to the Life History of I the Redeem Sunfish (Legends nicrologhus) in Michigan Waters“ presented by Vernon H. Cole has been accepted towards fulfillment of the requirements for u. 5; degree mm f. V ‘5 :-~ . r f ‘2' ‘ L.- Majoi professor L \ . 0 44 5% 00822002 :M .2120 ‘ $41 3 .0065 HAY 0 3 1996 .l'"".w [98%. .:_../ p N032141997 /L; - ‘I’IQI/ I CONTRIBUTIONS TO THE LIFE HISTORY OF THE REDEAR SUNFISH (LEPOMIS MICROLOPHUS) IN MICHIGAN EATERS by Vernon Walter ggle 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 1951 "THESIS .1!“ 4/: 9 /5/ )3)“ TABLE OF CONTENTS I. INTRODUCTION . . . . . . . . . . . . . . . II. ICHTHYOLOC aY OF THE REDEAR SUNFISH . . . . . A. B. C. D. Range . . . . . . . . . . . Description of the Redear Sunfish . . Morphological Differences of the Redear Sunfish, Bluegill, and Pumpkin- seed Sunfish . . . . . . . . Characteristics of the scales of the Redear Sunfish . . . . . . . . . . III. GROWTH OF THE REDEAR SUNFISH IN THE LABORATORY A. B. C. E. F. G. Methods of Feeding and Handling . . . Preparation of Food . . . . . . . . . Comparison of the Growth of uncrowded Redear Sunfish and the Bluegill . . 1. Bluegills . . . . . . . . . . . 2. Redear Sunfish . . . . . 5. Comparison of the growth of both species . . . . . . . . Comparison of the growth of the Redear Sunfish and Bluegill under crowded conditions 0 O O 0 O O O O O O O O 1. Bluegills 0 O O O O O O O O O O 2. Redear Sunfish . . . . . . . . 5. Comparison of both species . . The Redear Sunfish and the Bluegill in competition for food . . . . . . . Growth of the Redear Sunfish on natural food . . . . . . . . . . . Effects of Low water Temperatures on the Redear Sunfish . . . . . . . . IV. GROVTH OF THE REDEAR SUNFISH UNDER NATURAL CONDITIONS . . . . . . . . . . . . . . . A. N16 thOd S O O O . O O C O O O O O O O O l. Stocking the ponds . . . . . . . . 2. sampling 0 O O O O O O O O O O O 0 255918 OIOIOJH q 13 13 15 16 17 17 19 19 19 21 21 22 25 23 27 27 27 28 Growth of the Redear Sunfish in l. Pond 8, Hastings . 2. Pond 8, Wolf Lake . . 3. Pond 12, Wolf Lake . 4. Pond 17, Wolf Lake . HISTORY AND ECOLOGY . . . . Life History of the Redear Sunfish l. Spawning . . . . . . . 2. Hybridization . . . . . EC OLOGY 0 O O O O O O O O 1. Food habits of the Redear a. Qualitative . . . b. Quantitative . . 2. General Behavior . . . DISCUSSION 0 o o e o o o o o o SUNHVIARY o o e e o o o e o o o 0 LITERATURE CITED . . . . . . . . Ponds O O O I 28 28 28 29 29 34 34 34 35 38 38 38 4O 42 44 50 53 ACKNOWLEDGMENT The author wishes to express his gratitude to Dr. Robert C. Ball under whose direction this work was done. The author is also indebted to Dr. Peter I. Tack and to others, faculty and graduate students, who aided in the study. INTRODUCTION In many states to the south of Michigan, anglers catch a fish that they call a "stumpknocker" or redear sunfish whose scientific name is Lepomis microlophus. In these south- ern Waters this fish grows to a larger size than the abundant and popular bluegill of Michigan and from reports is highly regarded as a fine tasting sport fish. It has been stated by Krumholz (1950) that it is not as prolific as the bluegill and thus has less tendency to overpopulate smaller bodies of water. The redear has been stocked in Indiana as far north as Lake George, a lake lying both in Michigan and Indiana. From this lake it has moved into one or more lakes in southern Michigan connected with Lake George. In these lakes this species has reproduced and lived over winter. Since this fish has been reported to have many desirable characteristics, a study of its potentialities as a food and sport fish in small waters of Michigan was undertaken in the spring of 1950. Adults were obtained during 1949 and placed in a pond at Wolf Lake State Fish Hatchery. These fish spawned and the first fry were seen about the first of August of that year. From these fish it was possible to undertake several experiments to evaluate the redear sunfish as a pos- sible addition to the fishes of the ponds and lakes of Michigan. This thesis is a report of the experiments undertaken, both.in the laboratory and in natural waters, to determine whether the redear sunfish.would be a desirable species to introduce into the lakes of Michigan, and to contribute to the knowledge of the life history and ecology of this fish under conditions in the northern extremity of its range. ICHTHYOLOGY OF THE REDEAR SUNFISH The redear sunfish was first described by Gunther in 1859 and named Pomotis microlophus. Jordan and Evermann (1896) list this species as Eupomotis heros (Baird and Girard) with the synonyms of Eupomotis pgllidus, and E; holbrookii. According to Hubbs (1935) the name Pomotis heros given by Baird and Girard in 1854 was based on the bluegill (I? macro- chirus). bebs also found that the synonyms and other names previously suggested were based on hybrids or other species of sunfish and their descriptions did not fit the redear sun- fish. He also confirmed the fact that Gunther's name was the first valid one and suggested the name Eupomotis microlophus. However, Reeve Bailey (1938) recommended that the generic name Eupomotis be made a synonym for Lepomi . The scientific name of this species, therefore, is Lepomis microlophus. Hubbs and Lagler (1947) gave this fish the common name of western shellcracker. A special committee of the American Fisheries Society (1945) established the common name as the redear sunfish which will be used throughout this paper. Range The range of the redear sunfish, according to Hubbs and Lagler (1947), is from the Mississippi River in Missouri and southern Indiana south to Florida and the Rio Grande River. The introduction of the redear into the Lake Michigan drain- age of northern Indiana is also mentioned by these authors. The spread of this species into southern Michigan from northern Indiana was noted in the introduction. Forbes and Richardson (1920) state that the redear was found in the Wabash.River of Illinois and Indiana and in the Little Miami River of Ohio. The only lake in Illinois in which they found this species was Little Eagle Lake in Kosciusko County. From its original discontinuous range the redear has been introduced throughout Florida and possibly other southern or southeastern states, into Buckeye Lake in southern Ohio, and perhaps other lakes and streams for which.no records have been found. The present range of this species, as well as its range in 1930 as shown by Forbes and Richardson, is illus- trated in Figure 1. Within its range, the redear sunfish is most commonly found in large, warm rivers, bayous and lakes. Figure 1. Range of the Redear Sunfish Description of the Redear Sunfish The family Centrarchidae is characterized by two dorsal fins, which are connected, consisting of both spiny and soft rays. The scales are ctenoid or weakly ctenoid, and the air bladder is not connected to the esophagus. The redear sunfish can be recognized by the broad red margin on the fleshy cperculum, the short stout gill rakers, and the broadened pharyngeal arches with grinding pharyngeal teeth. According to Jordan and Evermann (1902) only the males have the broad red margin on the opercular flap but the mature specimens taken in the field had the broad red margin regardless of sex. Under certain conditions the fe- male may lose this coloration but it is evident in the fe- males in the lakes of Michigan. There are usually six scales above the lateral line, fourteen or occasionally fifteen below the lateral line, with the lateral line count varying from.36 to 40 scales. The dorsal fin normally has ten spiny rays and 11 soft rays, while the anal fin usually has three spiny rays and 9 or 10 soft rays. The longest spine of the dorsal is only 13.. thirds the length of the soft rays. The tip of the pee- toral fins extend past a line vertical from the origin of the last anal spine and the pelvics extend past the vent. Dr. Reeve M. Bailey (personal communication) states that there are considerable differences in the redear sunfish in dif- ferent portions of its geographic range. Within the limits 7 of Michigan, however, these differences are minimal and adult bluegill, pumpkinseed, or other sunfishes should be easily differentiated. Morphological Differences of the Redear Sunfish, Bluegill, and Pumpkinseed Sunfish The adult redear is not easily confused with adult blue- gills due to the broad red margin on the stiff opercular flap of the redear. The heavy, broadened pharyngeal arches with grinding teeth and the short gill rakers also distinguish it from the bluegill (Table l). The posterior region of the dor- sal fin in the bluegill has a dark blotch and the anal fin has one additional ray. The lateral line scale count for the blue- gill is usually from 40 to 46 scales and for the redear 36 to 40 scales. The bluegill has 5 rows of scales on the cheeks as compared to 4 rows on the cheeks of the redear. The paired, vertical dark bands on the sides of the bluegill, when apparent, are quite different from the single, interrupted bands which may be seen on the redear. The adult pumpkinseed sunfish.may be confused with the red- ear sunfish due to the fact that the pumpkinseed also has a red mark on the stiff, opercular flap. The redear has a broad red band the width of the opercular flap while the pumpkinseed has a circular red spot on the posterior edge (Table l). The red- ear has a flatter predorsal contour and is generally more rhom- boidac in form. The pectorals of the redear are more than one third of the standard length while the pumpkinseed has the shorter pectorals. The gill rakers and pharyngeal teeth of both of these species are stout and broad. The black when pmom m when pmom Hated when £90m 0H pdfloo when hcfidm n whey hdadm a when hedge n flaw dead when Hwano women Hep modes Hep dam Henseo Goospon muses teenage: on usoNHaon on Base prcoufiaos npmnoa Uhedaepm summed Upwnnwpm npwdod whenampm mHeHOpood unflapuoao omoe Unfiapuoqo weed unfinpnoco mmoa mo npwaoq paombw so medxoodm hHaOHmopmod Hemaoo pHOm peas“ ewefixawa xoean nopoan Mame do aoaoo when pmom Ha whey pace Ha peace when mnfidm 0H when hqfidm 0H can Henson phone paoflm whoa maoxwa HHHw manofiaomeQ haaofiaopmod hHaOHaomeQ oHoacdo mmapm «nape oHpHKeHm dfiwamfi do 9H» so pomm mean Ramp and“ amaze vamp mom pecan mom peach haoafipco uaodo do aoaoo mated wanna manna mafia Hwaepwd Boaon meadow m m m chad Heaepwa opens monom meson ownmn owuow mafia Hemopea do meadow phenom UcomnfixdESm Hafimosflm .mmHmZDm mmHmzpm ommmzHamspm 924 .equmqu m¢mgmm mus mo mmozmmmmmHQ Q000 ON. 00. 00 06 0* ON _ _ A _ _ 0 Inn [0 o '05 Too. I 2:: 15.0.3... mna Hm p.00 Hma H.5m moa onto mwamm omum oooa masooem oqu Mao; SH deem 0nd mma m.mmm 5mm n.4ba mam ooaumb owm mmem m.mo end m.oo oma m.mb med omum mwumw omnm oom mamooom mama “Ho; ma waom ¢.o me m.©m boa m.¢H mm omum menmm omum omwm chug «Ho; m deem HH mm an end b.0m NHH omnm mmnma mesa coma mmcfipmem m whom A.mawv *A.EEV A.mawv #A.EEV A.mewv *A.EEV mafiaaawm *A.EEV maHMOOpm UoROOpm oddadm GH cadaew Ga cadadm QH no open wafixoopm no open 909852 ouflm aaafiaag chum aaafixdz ouaw ewwaopw as onam mQZOm Nmmmoa¢m 2H mmHmZDm mdmmmm mo maaomw .w mumda 30 the redears in the Hastings pond (Figure 7). On the basis of this experiment it is evident that crowding is detri- mental to the growth of redears under natural conditions. Pond 12 Wolf Lake. This experiment was set up to determine the growth of the redear in combination with the largemouth.bass (MicrOp- terus salmoides). Stocking of this 1.6 acre pond was com— pleted in May, 1950 with 500 redears and 240 base. At the time of sampling the redears had gained 105 millimeters (Figure 7) in total length which is the best growth shown in the pond experiments. This probably is due to the lower level of stocking. The bass gained 125 millimeters in total length which is better than the Michigan average for this species. Pond 17 Wolf Lake. The bluegill-redear combination was stocked in this 1.3 acre pond in May, 1950 with 1,000 of each species. The redears and bluegills both gained about 65 millimeters in total length (Figure 8). This is a smaller gain than redears had shown at both the Hastings pond and in combination with bass in pond 12 but it is still considerably better growth than was shown by the crowded redears in pond 8 (Figure 7). From.this it appears that under natural conditions this com- 'bination of species in a lake would permit both species to approximate their normal growth rate. 31' Figure 7. Growth of the Redear Sunfish in hatchery ponds. 3..de hmaoa< >433 mzaa >5... Tov 100 loo I00. \ ma¢u0u¢ 100N— fill. Ibosz 44.3... _ mnj_@m3.._m IIII 33 Fry were also taken in the sample from this pond. The bluegill fry, which could be positively identified, aver- aged 25 millimeters in total length and made up a small per— centage of the total numbers present. The smaller fry of 12 millimeters total length were assumed to be redears due to the later spawning period of redears in the other ponds. Some of these smaller fry may have been from late spawning bluegills, but no morphological differences in the fry could be found to indicate this. The large numbers of redear fry would indicate that the redears spawned successfully. LIFE HISTORY AND ECOLOGY Little is known about the life history and ecology of the redear sunfish under the climatological conditions of Michigan, since this species is a sunfish of southern rivers and lakes where climatic and ecological conditions are quite different. Life History of the Redear Sunfish Spawning The ability of the redear to spawn this far north was demonstrated in Pond 3 at the Wolf Lake Hatchery by the adults seined from Silver Lake in 1949. No nests were observed, but on August 1, 1949 a large number of fry were seen in shallow water. These fry became the young-of-the-year redears that were used in the experiments the following year. In Pond 8 at Hastings a nest was found about July 24, 1950 and small fry were seen as late as September 1. The spawning site was in the midst of aquatic plants in about three feet of water and was similar in size and type to that of a pumpkinseed sunfish. These spawning fish were from Pond 3 at Wolf Lake and, therefore, were in their first year. The degree of success of this spawning is not known although a few young fry were removed from this pond. Both the redears and bluegills in Pond 17, Wolf Lake spawned with the bluegills spawning first followed by the redears as indicated by the much larger size of the bluegill fry. 35 Hybridization Two ponds at Wolf Lake hatchery were set up to obtain hybrids of the bluegill and redear for future study. Pond 4 was stocked in May, 1950 with eight adult, female redears and eight adult, male bluegills. In September, when the pond was drained, seven spawning beds were found and seven blue- gills emitted milt when pressed. The female redears appeared to be ripe and on handling dropped eggs. In addition to the brood stock two small fish resembling bluegills of 69 milli- meters and 59 millimeters were removed from the pond when the pond was drained in the fall, 1950. The scales showed that these two fish were spawned during 1950. From scale counts, length of fins, and other comparisons (Table 5) they were identified as hybrids of the bluegill and redear sunfish. Pond 5 was stocked in May, 1950 with four adult, male redears and four adult, female bluegills. When the pond was drained in September, four clean spawning beds were found but no eggs or fry were present. The two redear males found were ripe. Two redear males were lost in the dense weeds during the draining due to their habit of remaining in the vegetation as the pond is drained. The bluegill females were not carry- ing eggs. Temperature records from these two ponds show that the temperature seldom reached 700 F. Two reasons for these low temperatures are evident. It was a colder summer than is normal at this latitude and both of these ponds were near the cold springs which are the source of water for the ponds. penance Ham: Heoapaaaao pdomnw Lwapm flpmdod Unmodwpm oaazplodo Gena 090E phone mao> Owlom H meanssm meeeom mdofioadmeoo pom .Heeaoohafle ascend haaoaaomeQ oHQHNoHM dawned Unwonmpm pafiapnoao can» need cappaa pcomnm Udfion anemond hasoaaopmoa eafifiwoam flpmsoa dampnwpm Unfinpuono can» mmoa cappaa cum kusmo do upon mama meadow on» mo mfioom qemaoo mo aoaaop Inca no nepoam Aoaonv cacaodo meAOpood no hemmed esoaeh deem pddoo mason mafia Hemopwq wdoa wdoa mm oe-mm eaeeam Haemesam .b .0 .m .w .n .N .H monmmm mHmme oze .mmHmzpm memomm .oaqumpqm mo mOHemHmmeoememo .m mqmde 38 Temberature records from ponds in which the redear sunfish spawned successfully indicate that a temperature slightly above 70° F. for several days should bring about a successful spawning. Under existing fishing regulations, this poor spawning record would make it difficult for this species to overpopulate lakes and ponds as do the bluegills, perch, and other species. Ecology Food habits of the redear sunfish Studies were made to determine the ecological relation- ships and competition for food with other species. From the samples available it was possible to determine the organisms eaten during the period these fish were taken. Qualitative study. The stomachs of the redears from Pond 8 Hastings were analysed on a qualitative basis to determine the food preferences of redears. The intestines were also analysed to give additional information since the number of stomachs in the sample was small. The most important food items in the stomachs (Table 6) were Ephemerida (Family Baetidae), Dipterous larvae (Chiro- nomidae), and GastrOpods. The snails were so completely crushed it was impossible to identify them. Adult and nymphal ZHemiptera, especially the Family Corixidae, were also impor- tant food items but most of these were found in the intestine. 'The microcrustacea, which consisted primarily of Cladocerans, TABLE 6. RESULTS OF FOOD STUDY OF REDEAR SUNFISH Per cent of stomachs Number in Number in containing stomachs intestine organisms Ephemerida (Nymphs) Baetidae 76 15 78.5 Diptera (Larva) Chironomidae 51 50 57.1 Ceratopogonidae- 7 6 ,Tabanidae l 0 Syrphidae 6 O Hemipters (adults and Nymphs ) Corixidae 7 35 28.5 Notonectidae (Plea) 2 4 Belastomatidae 2 ColeOptera (Adults) Haliplidae 5 6 28.5 Odonata (Nymphs) Anisoptera 2 3 14.3 Microcrustacea Cladocerans 212+ 84+ 21.4 Copepods 4+ 2+ Mollusca Gastropods 32 43 78.5 Pelycopods (Pisidium) 2 8 Number of stomachs examined 14 Number of intestines examined 11 40 were in a few stomachs and made up a small percentage of the organisms. The AniSOptera found were all small members of the subfamily Gomphinae and appeared to be first instar forms. Quantitative study. The stomachs of the bluegills and red- ears seined from Pond 17 at Wolf Lake for growth data were analysed quantitatively to determine differences in feeding habits. One of the most important food items for both species were the Ephemerida (Table 7) of the family Baetidae. This order of insects, when found in the redear stomachs, was broken up and probably constitutes a higher percentage of the total volume than is indicated. While both species utilized Diptera larvae, especially the Chironomidae, to a large ex- tent, the redear consumed a much greater volume than the blue- gill. The microcrustacea were the most important group in the bluegill stomachs. The redears also utilized this group to a considerable extent. The Coleoptera eaten by the red- ears were entirely from the family Haliplidae while the blue- gills showed a marked preference for the members of the family Elmidae. A difference in preference in plant material was also evident. The redears had a considerable volume of the algae Hydrodictyon in their stomachs but bluegills preferred the higher aquatic plants such as Anacharis. Beetles of the family Haliplidae commonly feed on algae while the Elmidae are usually associated with the higher aquatic plants of shallower waters. Evidently the redear sunfish and bluegill take their food from entirely different types of ecological niches in a TABLE 7. ANALYSIS OF STOMACH CONTENTS or REDEAR SUNFISH AND BLUEGILLS FROM THE SAME POND Per cent of stomachs with Per cent of organisms Volume total volume a: W Diptera (Larvae) Chironomidae A. 57 .99 40.7 B. 71 .10 12.9 Ephemerida (Nymphs) Baetidae A. 85 090 57.5 B. 29 .22 26.9 Coleoptera (Adults) Haliplidae A. 21 .10 4.3 Elmidae B. 21 .05 5.5 Hemipters Notonectidae A. 21 .02 .7 Corixidae A. 7 .08 3.3 Trichoptera (Larvae) Limnephilidae A. 4 .02 .6 B. 5 .01 .5 Odonata (Nymphs) Zygoptera A. 14 .02 .7 B. 5 .032 3.9 Microcrustacea Cladocerans A. 85 .28 9.8 B. 69 .22 27.4 Mollusca Gastropods A. 7 .01 .1 Algae Hydrodictyon A. 28 .05 2.2 Higher Aquatic Plants B. 29 .19 22.9 Number of A. 18 stomachs B. 17 Number Empty A. 2 B. 4 {Total Volume A. 2.44 cc. B. .82 cc. ACT-‘Redears B - Bluegills 42 in a lake. The redear stomachs contained quite a few Hemip- tera which were not utilized by the bluegills. The total volume of organisms and food material in the redear stomachs was three times as great as that of the blue- gills. This would indicate more active feeding by the red- ears during midday when these fish were removed from the pond. General Behavior Observation of the redear sunfish in ponds and in the laboratory gave some indication of the general behavior of this species. The redears in ponds were seldom seen even when the ponds were approached with caution. Even when heavy concentrations of insects were on the surface of the water the redear was seldom seen to feed on them. This ten- dency to remain deep made it impossible to determine noc- turnal migrations. Fishermen of Silver Lake region state that, like the bluegill, the redear is never caught after dark by angling. Three adult redears of about five inches in length, were placed in a large observation tank, which had only one glass side. The bottom of the tank was covered with sand and stones to resemble a lake bottom. Shortly after the fish were introduced they appeared to become antagonistic. Eventu- ally one fish was vanquished to the upper regions of the tank and the remaining two appeared to have established territories on the bottom. They would defend their territory by spread- ing the gill covers and rushing at the invader with the mouth 43 open. Occasionally they would "square off" like boxers on what apparently was the border line of both territories. When food was introduced into the tank the redears at the lower level would move up and attempt to exclude the third from any food. If a large volume of food was put in at once, however, they would feed at the lower level en- tirely. They were quite adept at seeking out any live food which had escaped to the bottom. Most of the forms taken as food were chewed vigorously by the redear. Snails were crushed and most of the shell expelled from the mouth. Cased caddis larva were handled the same way. Stonefly nymphs were not accepted readily unless the redears had been starved for a few days. Soft forms such as Chironomus or Chaoborus larvae or pupae were readily taken and seldom chewed. Forbes and Richardson (1926) report that in association with other fishes the redear is never abundant in the lakes and streams of Illinois. This was reported by Krumholz (1949) to be true in Indiana. Roach (1942) found that, al- though the redear sunfish.became established in Buckeye Lake in southern Ohio from 57 breeders in 1934, as late as 1941 it was not a common species in the lake. This is explained by the fact that these regions are the northern limits of the _range for this species and reproduction is not as successful as native species. Krumholz (1950) points out however, that the redear maintains a slowly increasing population in Indiana lakes but does not overpopulate them. DISCUSSION The introduction of the redear sunfish into Lake George, Indiana, with the subsequent migration into Branch County, Michigan, brought a species of Centrarchidae new to this re- gion into the lakes of southern Michigan. This sunfish, when larger than a fingerling, is easily differentiated from other members of this family commonly found in Michigan. The broad red margin of the opercular flap, short gill rakers, and dark horizontal bars on the caudal fin are conspicuously different from the bluegill. The pumpkinseed sunfish, which also has short gill rakers and red on the ear flap, is distinguished from the redear by the dark speckles on the soft dorsal fin and the rounder form. The scales of the redear have an elliptical focus which is found only on this member of the family. The body length- scale length curve indicated that normally the redear develops scales at a total length of 15 millimeters to 22 millimeters. The young fry removed from Pond 17 welf Lake which were 12 millimeters in total length showed scattered melanophores which appeared to be covered by scale papillae. The range of this species originally was of a discontin- uous type from the Wabash River in Indiana and Illinois to the Rio Grande and northwestern Florida. It has been intro- duced into the Lake Michigan drainage of northern Indiana, several lakes in Illinois, several lakes and the Miami River of Ohio, and throughout Tennessee and Florida. 45 The laboratory phase of the study afforded an oppor- tunity to compare the growth of this species with the growth of the bluegill under controlled conditions. Tanks were stocked with redears and bluegills so as to produce crowded and uncrowded conditions. One tank of redears was fed natural foods, consisting largely of small earthworms, for comparison with the prepared food fed to fish in the other tanks, con- sisting of ground liver, cod liver oil, and a dry mix supple- ment. The prepared food gave much.better growth for both species than the natural food. The total gain in weight of the uncrowded redears did not compare favorably with the gain shown by the uncrowded bluegills. In addition to the bacterial diseases that were present, which.may have influenced the ability to gain weight (Lagler, 1927; Davis, 1946), it is also possible that the ratio established for not crowding may actually have crowded the redears. Under crowded conditions both species had a much slower gain in weight than the uncrowded fish. The mortality rate of these crowded fish was much higher than that of the un- crowded fish. Redears and bluegills were put into the same tank to determine their reaction to competition for food. The blue- gills quickly showed dominance in feeding indicating that should these two species occupy the same ecological niche in a lake the bluegills presumably would be the dominant species. The reaction of redears to cold temperature was compared 46 to the reaction of bluegills by moving a tank of each species into the controlled temperature room. At lower temperatures the redears refused to eat and had a high.mortality rate. At these same low temperatures bluegills would feed to a limited extent and suffered a lower mortality. 0n the basis of this experiment it would appear that the winter conditions would cause a high.mortality of young-of-the-year redears. From the failure to feed at lower temperatures under labora- tory conditions it would appear that this species would sel- dom enter the catch of the ice fisherman. The stocking of young-of-the-year redears in ponds at the Wolf Lake Hatchery and Hastings Hatchery gave an oppor- tunity to determine their growth and ecology under natural conditions. Pond 8 at Hastings was stocked with 1200 redear fingerlings in August of 1949 and one year later, when the sample was taken, they had shown excellent growth. These redears spawned in late July of 1950 and were successful as fry were seen in August of 1950. Pond 8 of Wolf Lake was also stocked with redears but with twice the number put into the Hastings pond. The growth of these more crowded fish was not significantly less than the uncrowded redears of the Hastings pond. The crowded sunfish, however, apparently did not spawn. One pond was stocked with both redears and bluegills to determine the growth of the redear in competition with the bluegill and to ascertain the degree of competition for food. The growth rate of both species was the same from May 1950, 47 when the pond was stocked, until the sample was taken in (September of 1950. Both species spawned successfully with the bluegills spawning first since the bluegill fry were much larger. There were a great many more redear fry than bluegill fry in the sample. A combination of redear sunfish and largemouth bass was stocked in Pond 12 at Wolf Lake Hatchery in May 1950. In September of 1950, when a sample was taken, both species had shown remarkable growth. Krumholz (1950) points out that this combination has proved to be superior to most others for stocking the ponds of Indiana. An attempt to produce bluegill-redear hybrids in to ponds at Wolf Lake Hatchery had a small degree of success which.means that these two species may hybridize under natural conditions in this climatic zone. A pond at Wolf Lake Hat- chery was stocked in May 1950 with adult female redears and adult male bluegills. When this pond was drained in Septem— ber 1950 only two fry, later identified as hybrids, were found. Another pond that was stocked with.male redears and female bluegills, contained spawning beds but no eggs or fry were found. Mr. Shelby D. Gerking (personal communica- tion) reported that the Indiana hatcheries had no difficulty in producing hybrids of bluegills and redears in ponds during this same period. The poor results in both these ponds was probably due to the colder water temperatures of a cool sum- mer and the proximity of the ponds to the cold springs which were the source of the water for the ponds. 48 The redear sunfish in ponds and in the laboratory afforded an opportunity to study some of the ecology of this species. The stomachs of the fish removed from the ponds were analysed to determine the feeding habits of this species. It was found that they had fed largely on mayflies, snails, and other hard forms such as aquatic beetles and water boatmen. Accord- ing to Ball (1948) and Ball and Tanner (1951) a large percen- tage of the total volume of food of the pumpkinseed sunfish is also the Gastropods and hard forms. In a study of the stomach contents of redears and bluegills from the same pond, an association of plant material taken and the beetles eaten was noted. The redear stomachs contained algae and beetles of the family Haliplidae which feed on algae. The bluegills had eaten the beetles of the family Elmidae which is found on the higher aquatic plants. 0n the basis of this the redear sunfish has an entirely different type of ecological niche than the bluegill. This species apparently is an active feeder during the midday since the stomachs of the redear sunfish taken during this period contained three times the volume of organisms found in the stomachs of the bluegills in the same sample. The general behavior of the redear was observed both in the laboratory and the field. These fish are seldom seen in ponds since they remain almost constantly in deep water. The habit of remaining deep made it impossible to observe diurnal or nocturnal migrations. Fishermen in Branch County, however, report that it is never caught after dark so it is probably 49 inactive during the hours of darkness like most other sun- fish. Observations of adult redears in large display tanks showed that they establish territorial rights and defend them vigorously. Redears chew most forms of food, with the possible ex- ception of smaller and soft forms such as Chaoborus or Chiro EEEEE‘ Snails and cased caddie larvae are crushed and most of the debris expelled from the mouth. The redear sunfish should be a desirable species of Centrarchidae for the stocking of ponds in southern Michigan. It has demonstrated that it grows well in this region and has been successful in spawning. This species in combination ' with the large mouth.bass should be more satisfactory than the bluegill-bass combination now in use. This fish also can be stocked in lakes which contain bluegills since they occupy different ecological niches as indicated by their feeding habits. SUMMARY The redear sunfish (Lepomis microlophus) is a species of the family Centrarchidae new to the state of Michigan. It is found in Silver Lake, and possibly others, of Branch County. This species is easily recognized by the broad red mar- gin on the opercular flap, the short gill rakers, long pectorals, and the dark stripes running along the dermal rays of the caudal fin. The growth of the redear in aquaria did not compare favorably with that of the bluegill. The stocking ratios used may have caused a crowded condition in the redear tanks which.was not evident in the bluegill tanks. The bacterial diseases which.were known to be present may also have had an effect on the rate of growth. In the same tank with bluegills, the tendency of the redear sunfish to remain near the bottom.made it impos- sible for them to get much food. The addition of redear sunfish larger than the bluegills already present did not overcome the dominance of the bluegills. The young—of-the-year redears in the laboratory suffered a high.mortality rate at temperatures approximating win- ter water temperatures in Michigan. 10. 51 The growth of redears in hatchery ponds was comparable to growth of bluegills under similar conditions. Crowd- ing of redears in a pond caused a reduction in growth rate for the experimental period. The association of algae and beetles of the family Hali- plidae was found in the redear sunfish while the associ- ation of higher aquatic plants and beetles of the family Elmidae was found in the stomachs of the bluegills in the same pond. This is due to the fact that bluegills occupied a different type of ecological niche than the redear sunfish. The redear sunfish and largemouth bass stocked in the same pond both had excellent growth. This may have been partly due to the higher biological productivity of the pond used. Discounting this possibility, the growth rate of both species was still much.better than the average growth for the redear sunfish and largemouth bass in other ponds for the same period. The redear sunfish will spawn successfully in this climr atic zone of southern Michigan. The temperature require- ments are higher than those of the bluegill which.means that they usually spawn later than bluegills. The redear will hybridize with the bluegill under natural conditions. The two hybrids produced in hatchery ponds indicated that such hybrids have excellent growth. 11. l2. 13. 14. 52 Redears eat many hard forms such as snails, fingernail clams, water-boatman, and aquatic beetles. The beetles of the family Haliplidae are associated with algae which was occasionally found in redear stomachs. The redear sunfish is usually found near the bottom in deep water and is seldom seen. According to fishermen it is never caught after dark so it is assumed that the diurnal and nocturnal migrations are similar to the blue- gills. The redear sunfish should grow well and reproduce in ponds in southern Michigan. The combination of this species and large mouth bass should prove preferable to the bluegill- bass combination now in use. While the redear sunfish would probably not be taken by ice-fishermen, it could provide good fishing in some of the southern Michigan lakes in combination with the bluegill, bass or other species. A possible exception may be those lakes which contain large populations of the pumpkinseed sunfish. LITERATURE CITED Bailey, Reeve M. 1938 Revision of the genera of the family Centrar- chidae. Misc. Pub. Univ. Mich. Mus. Zool. Ball, Robert C. 1948 Relationship between available fish food, feed- ing habits of fish, and total fish production in a Michigan Lake. Tech. Bull. 206, Mich. State College Agr. Exp. Sta. Ball, Robert C. and Howard A. Tanner .1951 The biological effects of fertilizer on a warm- water lake. Tech. Bull. 221, Mich. State College Agr. Exp. Sta. Creaser, Charles W. 1926 Structure and growth of the scales of fishes in relation to the interpretation of their life history. Misc. Pub. Univ. Mich. Mus. Zool., 17. Davis, H. S. I 1946 Care and diseases of trout. U. S. Fish and Wildlife Service, Invest. Rept. 12. Forbes, S. A. and R. E. Richardson 1920 Fishes of Illinois. Nat. Hist. Surv. I11. v01. 3. Gerking, Shelby D. 1945 The distribution of the fishes of Indiana. Invest. of Ind. Lakes and Streams, Vol. 3, No. l. Hubbs, C. Le 1927 The related effects of a parasite on a fish. Journ. Parast., 14 1935 The scientific name of two sunfishes, Helioperca macorchirus (Rafinesque) and Eupomotis micro- Io hus (Gunther). Occasional Papers of Mus. of 2001. No. 305, Univ. of Mich. Press ‘ HUbbS, C. Lo and KO Fe 118.819]? 1947 Fishes of the Great Lakes region. Cranbrook Inst. of Science, Bull. No. 26. Jordan, D. S. and B. W. Everman 1896 Fishes of North and Middle America. Bull. U. 3. Nat. Museum No. 47. 54 Krumholz, Louis A. 1950 New fish stocking policies for Indiana ponds. Trans. Fifteenth N. Amer. Wildlife Conf. Lagler, Karl F. 1941 Lepidological study 1. Scale characteristics of the families of Great Lakes fishes. Trans. Amer. Micros. Soc., Vol. 46, No. 2 Moore, Walter G. 1941 Studies of the feeding habits of fishes. Ecol. (22) 1 Roach, Lee S. 1942 Fish population of Buckeye Lake as determined by trap nets. Ohio Jour. Science, No. 6. Welsh, Paul S. 1935 Limnology. McGraw Hill Book Co., New York, N. Y. 1945 Common and scientific names of better known fishes. Amer. Fish. Soc. Special Pub. No. 1, Trans. Am. Fish. Soc., 1945, 76. ROOM USEVONIY «I W ROOM USE ONLII" Mv28'fl ", a .1 . flit-I »‘ ““”.""}"‘ 3‘1 «NOV-Lam bfl 1‘! .. I} I "‘IIIIIIIIIIIIIIIII“