TPWD 1953 F-7-R-1 #16: Job Completion Report: Laboratory and Statistical Analysis of Materials and Data Collected in the Field, Region B-1, Northcentral Texas

STATE_ Texas m PROJECT N0. EmT—Rwl, Job s—u m PERIOD June 152 1953 — May 31: l95h JOB COMPLETION REPORT by Leo D. Lewis and Walter W. Dalquest Laboratory and statistical analysis of materials and data collected in TITLE the field. OBJECTIVES l. 2. TECHNIQUES l. 2. 3. u. 5. 6. To determine the following data from laboratory examination of field collected specimens: a. Growth rate of the species present. b. Food habits. c. Sexual development and spawning success. d. Comparative physical condition (coefficient of condition). To determine pepulation estimates and trends from field data. Attempts were made to determine the growth rates of the more impor- tant species of fishes by correlation of length and weight with age determination from scale readings. Preserved stomachs of predatory species, when they contained food, were examined in the laboratory. Sexual development and spawning success, spawning seasons and the rem productive potential (egg counts) were determined in the field and laboratory. The coefficients of condition were computed in the laboratory for all specimens collected, after the formula presented by Carlander (Fresh Water Fisheries Biology.) Analysis of relative abundance of species is based on field—taken gill net collections supplemented by rotenone samples aniappropriate mathematical treatment. Pathological conditions that might affect future pOpulation trends were diagnosed and recorded whenever discovered in the field. FINDINGS The findings under this job are so varied and unrelated that they are best discussed under the following separate headings: 1. Age determinations from scale readings. 2. Food habits of predatory species. 3 Reproduction. h. Coefficients of condition. 5. Relative abundance of species. 6. Pathological conditions. The headings apply, in each case, only to the three lakes studied during the past project period, in Region B-l, northcentral Texas. Details on the lakes, their ecology and fish populations are discussed in completion reports for Jobs 3.1, 3-2 and 13-3. AGE DETERMINATION In the field, samples of scales of every specimen taken in gill nets were saved for laboratory examination. Suitable equipment and materials for reading scales were borrowed from Midwestern University. It was originally suggested in our project proposals that doubt existed as to the validity of annuli on scales in determining the agecf fishes from this latitude. After many hours of study we summarize our findings as follows: 1. Many scales present apparent annuli that seem logical as age rings in consideration of the length and weight of the fishes from which the scales were removed. 2. Scale markings are usually duplicated on most scales from any individual fish. 3. For every specimen with logical ”annuli", there is at least one specimen of the same species that gives ridiculous age readings. h. The bulk of the specimens examined do not present scale markings recognizable as valid annuli. . We are forced to conclude that annuli on the scales of fishes from this region, if valid for age determinations at all, will require far more time and detailed study than we can spare for them. In this region, winters are mild and the lakes rarely freeze. Insect and plant life is available throughout the year. It is possible that scale marks reflect violent ecological conditions such as drouth, excessive salanity or sudden floods rather than regular yearly growth stages. 3. We do feel, however, that scale markings may show, or at least indicate in a general way, age of the specimens. If the "ridiculous" specimens are discar- ded and the doubtful specimens read as best they can be determined, the results are in fair agreement with what we would judge from size and weight. Neverthdess we have no confidence in the results and would rather depend on length and weight as age indicators. FOOD HABITS OF PREDACIOUS SPECIES The stomachs of all predacious fishes were examined in the field. Those stomachs that contained food were removed, labeled and preserved in 10% formalin. In the laboratory these stomachs were opened and examined, under a microscope, when necessary. Only those food items that could be identified with reasonable centsinty were recorded. The differences in the forage fish species in the three lakes and diversity of food items found, makes it impossible to present the data obtained.in a uniform way. Lepisosteus osseus. (Absent from Lake Kemp) The single specimen (and only gar of any species taken) from Lake Kickapoo contained a gizzard shad (Doro- some cepedianum) lhO mm. in standard length. Three specimens from Lake Diversion held four small white bass (Morons chrysops) 65, 67, 85 and 90 mm. in standard length and an adult bluegill (Lepomis macrochirus) 127 mm. in standard length. The latter fish would scarcely fit in the stretched mouth of the dead gar. mLepisosteus productus. (Absent from Lake Kickapoo.) No stomachs with identifiable food remains were taken in either Lake Kemp or Lake Diversion. ' ‘ '“ ' ‘ ' ' - - .- Lepisosteus platostomus. (Absent from Lake Kickapoo). Four specimens from Lake Kemp held food, as follows: I gizzard shad, ca. 150 mm., 2 white bass, 155 and ca 150 mm.; 1 small drum (Aplodinotus grgnniens), ca. 185 mm. in standard length. One specimen from Lake Diversion held a white bass about 75 mm. in stan— dard length. Hiodon alosoides. The single specimen taken in the course of the study (from Lake Diversion; held a shortuhorned grasshopper with tegmina #2 mm. in length. Ictalurus punctatus. The channel catfish is present in all three lakes but is most numerous in Lake Kickapoo. A total of 66 stomachs containing identi— fiable food items were examined. Plant material occurred in nine stomachs. Two stomachs contained only a feltnlike mass of green algae and mud; one contained algae, mud and about 100 midge larvae. Three stomachs contained nothing but wheat grains and hulls; one contained wheat and insects. This material presumably came from "baited fishing holes,” probably baited to attract crappie. One stomach contained, in addition to other food, a single large grain of corn. Another contained a small amount of plant fiber, possibly grass fiber, in addition to other food. Earthworm was detected in a single stomach; possibly it represented bait. A crayfish was found in one stomach and several isopods (pillbugs) in another. One stomach held two spiders, another held three spiders, and one held a large ”scorpion. 4. One large catfish had eaten a small bird of the finch type; possibly an English sparrow (Passer domesticus). It is possible that this was bait; probablyit was carrion. Bait (chicken heads, bird or mammal intestine) and trash (dragonfly droppings, mud, gravel, bologna sausage rind, etc.) was present in 13 stomachs. The mud and gravel appeared to have been eaten accidentally. The bulk of the food items identified consisted of insects and fish. The popular notion that catfish will eat "almost anything" is well borne out by our investigations. Nevertheless some astonishing facts were discovered, es- pecially with regard to the insects eaten. The bulk of theinsects was land in - sects; many were flightless types. Individual fish showed great selectivity. In the same nets catfish were taken with only insects in their stomachs; others with only fish; others yet with both fish and insects. In general the smaller fish took insects and the larger ones were pisciverous. m E; 1" TABLE 1. FREQUENCIES OF OCCURRENCE AND NUMBERS OF INSECTS, IDENTIFIED TO FAMILY, FROM STOMACBS OF 37 CHANNEL CATFISBES, ICTALURUS PUNCTATUS. Rood Item . __ _. _H.._ ..-H_,. ,,__‘_ P'Frequency of'” . 'InTotal Number (_occurrence__ identified Mayfly nymphs (Ephemeroptera) 1 7 Mayfly adults (Ephemeroptera) 3 10 Grasshoppers (Locustidae) 23 286 Crickets (Cyrillidae) l 1 Earwigs (Dermoptera) l 1 Termites (Isoptera) 1 1 Water Boatmen (Corixidae) 1 1 Backswimmers (Notonectidae) 3 209 Assassin Bugs (Reduviidae) 5 9 Damsel Bugs (Nabidae) (?) l 17 Plant Bugs (Miridae) 3 17 Chinch Bug (Lygaeidae) 2 12 Squash Bugs (Coreidae) 2 6 Stink Bugs (Pentatomidae 11 1&0 Leaf Hoppers (Cicadellidae) 12 3333 Green Lacewings (Neuroptera) 2 10 Ant-lion Larvae (Neuroptera) 1 11 Gall Wasps (Cynipoidea) 2 2 Velvet Ants (mutillidae) 2 2 _Digger Wasps (Scoliidae) 1 l Ants (Formicoidae) A 13 Tiger Beetles (Cicindelidae) A A Ground Beetles (Carabidae) 12 1175 Diving Beetles (Dytiscidae) 1 3 Whirligigs (Gyrinidae) 1 1 Click Beetles (Elatridae) 1 s Metalic Wood Borers (Buprestidae) 2 2 Ladybugs (Coccinellidae) 3 A Darkling Beetles (Tenebrionidae) 2 2 Scarabs (Scarabeidae) 2 5 - Leaf Beetles (Chrysomelidae} 6 15 _Weevils (Curculionidae) 1 3 Moths (Lepidoptera) 2 7 Angelwing Butterflies (Nymphalidae) 1 7 Mosquitos (Culicidae) 1 100 Midge Larvae (Chironomidae? 1 113 - -q--. TABIE ll. FREQUENCIES OE OCCURRENCE AND NUMBERS OF FISHES FROM STOMACHS GE 22 CHANNEL CATFISH, ICTALURUS PUNCTATUS Wmflmm m Food Item ‘ Frequency of flnflh Total Number -m: _ _ Occurrence Identified Gizsard shad (Dorosoma cepediangmi 15 18 . 'Carpsucker (Carpiodes carpio 1 1 Minnow (NotrEpis lutrensisi 1 1 1White bass (Morons chrysops) 1 1 Crappie (Pomoxis annularisi A A iDrum (Aplodinotuslgrunniens) A 5 6. Some catfish, both large and small, preferred insects of a given size. Some stomachs contained only relatively large insects such as grasshoppers and beetles. Others had eaten hundreds of tiny species, like leafhoppers. Some fish seemed to prefer insects of a green or greenish color. When the stomachs of these fish were opened, the food mass had a distinctly greenish color, com- ing from numerous different insects of different families and orders but all or mostly greenish in color. Most, perhaps all, of the land insects eaten must have been taken from the surface of the water. Many were blown into the water by wind. That the catfish took the insects from the surface is well shown by the presence in 12 stomachs of dragonfly droppings. These small, dark balls of chiton puzzled us for some time until it was learned that dragonflys deficate in midair. Compar- ison of known dragonfly droppings with the mysterious balls of chiton from cat~ fish stomachs made_identification certain. It also suggests that the surface feeding catfish ftmkiby'smell rather than by sight, on material resting on the surface film of the water. Rises in lake level following rains are reflected in the stomach con- tents of catfish. Following lake rises, the numbers of flightless and rarely flying insects in the diet of fish increases. The greatest numbers of carabid beetles were found after heavy rains. The catfish with 11 antmlion larvae in its stomach was taken after a rain. Surprising also is the nature of some of the insects eaten. Insects such as velvet ants and assassin bugs can inflict painful stings or bites. These forms may have been taken while dead. Some odorous forms, such as tenebrionid beetles and stink bugs are eaten. Indeed, one species of large stink'bug (Nazare viridula) was often eaten and constitutes most of the stink bugs eaten. It is noteworthy that blister beetles, known to be extremely poisonous, at least to man, were absent from catfish stomachs though they are common on the vegeta- tion aboutthe lake and must often have fallen into the water. In general however, a distinct preference i.s noted for grasshoppers, true bugs (sspeciall y stink bugs and leaf hoppers}_ and beetles {especially green— ish carabids. ) Some seasonal variation in insect diet was noted. Grasshoppers were most common in the fall of the year. 'Mayflies were eaten only in the summer. However, the diet of small catfish consists of insects, even in midwinter. Stemw ache taken in January and February, following periods of subufreeahg weather, contained nothing but insect remains. Most of the wintermtaken insects were leaf hoppers and backswimmers. Only channel catfish of three pound weight, or over, fed exclusively on fish. Some smaller catfish had eaten both fish and insects. Apparently small catfish eat fish when they catch them, but only larger and older catfish are adept at capturing fish. Most of the fish eaten were quite small but only one was a "forage fish? Young gisaard shad, drum and crappie made up the bulk of the fish food. The food habits of the larger, pisciverous catfish is quite sins ilar to the food habits of the other predacious fishes. Eilodic tus olivaris. Only five filled stomachs were obtained from flat- head catfish. These large catfish seem to be entirely pisciverous. One had eaten 2 Dorosoma cepedianum and. a Notropis lutrensis;. another had eaten one Pomoxis annularis, one had eaten ten shad {Dorosoma. cepedianum), LEMMA-'1 no: some of modern maul-mm m 7. Morone chrysops. We obtained 73 white base that contained identifiable food in their stomachs. Of these, 27 were young specimens captured while feed- ing on enormous hatches of sub—image and adult mayflies of the genus Hexagenia. Another specimen held ten nymphs of a mayfly, probably Hexagenia; Another held, in addition to a small fish, a nymph of a dragonfly. A total of #5 specimens had eaten fish, mostly small, as follows: TABLE 111., FREQUENCIES 0F" OCCURRENCES AND NUMBERS: OF FISHES EATEN BY WHITE BASS (mesons Gmnsors), BASED ON 15 safer/moss. 'Freqnency'of" 'Total Nnmber' C'Food Item .“ ..e¢eerrense_.. ”_ifientifiefl IDorosoma cepedianum 2h 27 Hotropis lutrensis 3 h Notropis venustus l l Pimephales vigilax l l Lempois (megalot is '2) 2 2 1h 17 Aplodinotus grunniens A total of 32 stomachs of black bass, with iden Of these, l7 were of small fish, taken in seine The 17 stomachs were The remaining 15 Micropterus salmoides. tififiable food was examined. hauls during an enormous hatch of the mayfly, Hexageniao crammed with sub-image and adult mayflies and nothing else. stomachs contahed fish, as follows: TABLE 1V. FREQUENCIES OF OCCURRENCE AND NUMBERS OF FISHES EATER BY BLACK BASS (MICROPTERUS SALMDIDES), BASED ON 15 STOMACHSO Food Item 'Freqnency'of"m'TotaliNumber“ __Occursense m,.w Idenfiified_.__ Dorosoma cepedianum 10 13 Notropis lutrensis 2 2 Aplodinotus grunniens 3 5 Pomoxis annularis. Crappie are present in all three lakes but are es— pecially abundant in Lake Kickapoo. We obtained 63 stomachs that held identi— fiable food items. Of these, six stomachs were of fishes taken in areas where the mayfly, Hexagenia, was swarming. The stomachs of these 6 fish were crammed with the remains of the insect. The total food items identified are as follow: 8. TABLE V. FREQUENCIES OF OCCURRENCE AND NUMBERS OF FOOD ITEMS EATER BY CBAPPIE, POMOXIS AEEULARIS, BASED ON 63 STOMACHS. 'Food Item .... ._ 'CUIIIIIIHI'nli'Freqnency‘of' 'Total Number _nOCcurence _____ __Identified_ Dorosoma cepedianum 37 4h lotrOpis lntrensis l3 lh Pimephales vigilax l l *plodinotus grunniens 6 6 Grass Shrimp (Palemanotes) 2 2 .ayflies (Pentagenia) l l Layflies (Hexagenia) ‘ ll hh3 Aplodinotus grunniens. Only two drum with food in their stomachs were obtained. One of these held a shad (Dorosoma cepedianum). The other held a shed (Dorosoma cepedianum) and a much smaller drum. Apparently the species is cannibalistic. CONCLUSIONS. Except for the insects, so important to the catfish, and the occasional hatches of mayflies, the important food items for the game fish- es of the lakes seem to be shad and small drum. The soucalled forage fishes, in spite of their great abundance, are of only nominal value. REPRODUCTION All fishes taken in gill nets, and most specimens taken by other means were opened in the field and the stages of sexual development were recorded. Sheer bulk of the material precluded detailed description of develOpmental stages while the number of individuals making observations and their differen— ces in judging finer stages of development, made it impossible to record more than the most basic data. Therefore femal gonads were classed into only three groups: (1) ripe - with large or relatively large eggs, readvtoabe laid or nearly ready, (2) - immature — eggs small or inconspicuous_and obviously not ready to be laid and (3) spent — with ovaries from which eggs had recently been expelled. Male gonads were judged in a similar fashion, on the basis of the size of the testes. Ripe ovaries were preserved and the eggs counted only.during the later stages of the project. We regret that this was not begun sooner for checking of the literature discloses little data as to the numbers of eggs laid by some of the species of fishes most common to our waters. Ovaries containing large eggs were carefully weighed on a chemical balance, to the nearest tenth of a gram. A small portion of the ovary, approximately one gram, was then snipped free and weighed on an extremely accurate balance to the nearest ten milligrams. The eggs in this small portion were counted and the total eggs thus estimated. Times of spawning and spawning success we found extremely difficult to determine, at least in an accurate and comparable way. The data on this aspect of the problem is generalized from the number and date of findings of spent ovaries, fry and young fish taken in minnow seines, and fry found in the stomachs of the predatory species. In this connection we have utilised some field notes from waters other than the three lakes studied in detail but located within a few miles of these lakes. The varied nature of the information obtained makes it impossible to present it in tabular form but brief summaries for each species are offered here— with: Lepisosteus osseus -.A female weighing 1,600 grams contained 40,992 eggs. One gar only about three inches in length was taken in backwater near Lake Divers- ion on June 21, l953 but no small specimens were taken in any of the lakes stud- ied. Individuals with ripe ovaries were taken throughout the year and we do not believe gars in the lakes studied laid any eggs during the project period. Lepisosteus platostomus — No egg counts available. As is true of the longnosed gar, the shortnoscd gar apparently did not breed durhg the project per- iod. Females with ripe ovaries were taken during the entire year and no young gars were taken in the lakes. Lepisosteus productus » A female weighing 902 grams contained 77,572 eggs and another weighing 955 grams, contained 71,0h8 eggs. Ripe females were taken‘through.the project period and we found no evidence of breeding in the lakes studied. Dorosoma cepedianum - No egg counts available. Heaviest spawn came about June l5,ml953. After this date hundreds of small shad were taken in seine hauls, but such small shad were notably scarce in Lake Diversion. In the food of pred- ators also we found shad rare in Lake Diversion but abundant in Lake Kemp and Lake Kickapoo. hfter the major spawn, in June, spawning continued throughout the period at a reduced rate. However, even in January l95h, nets set under the ice of Lake Kemp took numerous shad about 30 mm. in standard length and obviously only days of age. Ictiobus Icyprinellus — No egg counts or spawning data avala.ble. one specimen about three inches in total length wa.s taken on June lo, l95h.. Ictiobus bubalus w Egg counts are as follows fisn of 950 grams weight, 67,l00 eggs, l,875 grams, 9%. 770 eggs; 2 ,h90 grams, lM ,136 eggs; 2,650 grams, 182 ,120 eggs; 2 7 5 grams, 199, 209 eggs; l ,375 grams, 15?,5tt eggs. Ripe fe- males and fry were taken throughout theyear. Ovaries with large eggs were re« corded during every month of the project period. Carpiodes carpio - Egg counts from two females: fish of 650 grams, 192,6H0 eggs; 950 grams, lll,llO eggs. Ripe females and fry were taken through~ out the year. Fry live in dense schools in shallow, muddy water until approxi— mat.ely three inches in length. Fry taken during all m.onths of the project per- iod. This species definitely spawns in the lakes rather than in streams enter~ ing the lakes. Spawning highly successful in all three lakes Cyprinus carpio - Egg counts of three females are as follows: fish of 205 grams (possibiy one year old), l3,6lO eggs; fish of 2,250 grams, 198, 068 eggs; fish of 1,820 grams, 379,8h0 eggs. Breeding appears to be restricted to mid - June, at least in 1953. Fry appear in streams and backwaters of lakes for several weeks, until about four inches in total length. None encountered thereu after until fish of approximately eight inches are taken in gill nets in the following March. Spawning moderately successful in all three lakes. 10. Ictalurus punctatus - Egg counts of two females are as follows: fish of 2,300 grams, 11,228 eggs; fish of 2,650 grams, 11,091 eggs. Heaviest spawn seems to occur in September and October but occasional ripe females are taken through the year. Fry are rarely taken in seines but fish 6 to 8 inches in length and thought to be about a year old are taken in gill nets. Spawning highs 1y successful in Lake Kickapoo, moderately so in Lake Diversion and very poor in Lake Kemp. Pilodictus glivaris - one female weighing 3,050 grams contained 10,218 eggs. No fry and few even moderatiy small individuals were taken. Morons chrysops _ No egg counts are available from lakes studies. Gill nets, seines and hook-and—line fishing show spawn highly successful in Lake Diw version, but poor in Lakes Kemp and Kickapoo. Micropterus salmoides — Egg counts are as follow: Fish of 2,300 grams, 95,816 eggs; 2,560 grams, 73,260 eggs ; 3,300 grams, 137,720 eggs. Seining checks show the reproduction of this species in Lake Diversion to beligfly satisfactory. Nearly every seine haul in the shallows revealed numerous small black bass. Re— production in Lake Kemp and Lake Kickapoo, on the other hand, was very poor during the project period. Pomoxis annularis — Egg counts are as follows: fish of 2% grams, h,520 eggs; 102 grams, 7,150 eggs; 120 grams, 8,880 eggs, 129 grams, 9,920 eggs; 388 grams, 15,1h8 eggs. An abundance of small crappie were taken in Lake Kickapoo during every month of the year and females with ripe ovaries were taken during most months. The heaviest spawn occurs in June and July, however. Spawning dur~ ing the project period was highly successful in Lake Kickapoo and moderately so in Lake Kemp and Lake Diversion. Aplodinotus ggunniens - Egg counts are as follows: fish of 236 grams, 9,020 eggs; 575 grams, 9,900 eggs; 529 grams, 10,680 eggs; 236 grams, 10,7u0 eggs; 760 grams, 12,800 eggs; 590 grams, 13,120 eggs. Data here is contradictory. Ripe females were taken only in May and June but small fish, less than two inches in length were taken in all months of the year. We believe that some females, at least, breed during all months although the major spawn takes place in late May and early June. Spawning highly successful in all three lakes but especially so in Lake Diversion. COEFFICIEETS OF CONDITION The coefficients of condition, or “K” factors, have been worked out sep- arately for each lake. Statistical treatment showed distinct differencgh ?. “he average "K" factors for males and females. Separation by seasonal singles indie cated some increase in the "K” factors in fall and early winter but, in'acst in— stances, the differences were not significant, probably because such separation reduced the samples so greatly. Contrary to expectation, no correlation between age and ”K" factors was discovered except in the case of black bass and crappie. In black base, the “K” factor increases rapidly in large fish. in very small crappie, the "K” was larger than for nature specimens. Because of the possible comparisons and statistical treatments that might be desired by other workers (we have used standard deviations and the stan- dard error of the mean in our own work) we have presented in the following tables a brief summary of our actual findings;