Journal of the Southeastern Association of Fish and Wildlife Agencies

During summer, 1976, fish population data were collected by gillnetting, electrofishing, and seining from 30 flood prevention lakes that maintained coexisting populations of white crappie (Pomoxis annularis), largemouth bass (Micropterus salmoides), and bluegill (Lepomis macrochirus). Abundance and size composition characteristics for white crappie were compared by simple correlation techniques to abundance and size composition characteristics for largemouth bass and bluegill Total numbers of white crappie were not significantly correlated to total numbers of largemouth bass or bluegill Numerous relationships existed between white crappie and largemouth bass/bluegill size structure variables. Flood prevention lakes that maintained balanced largemouth bass/bluegill populations, also maintained populations of white crappie having diverse size distributions.

A 45-cm (18-in) minimum size limit was placed on largemouth bass (Micropterus salmoides) in January 1978 in 4 North Carolina reservoirs. Annual spring electrofishing samples were conducted to obtain size distribution information on each lake, length-weight information on 2 lakes, and largemouth bass population estimates on one of the study lakes. After a 4-year investigation, the proportion of quality size bass in the stock size distribution of 2 lakes increased. On a 3rd lake, a newly developing largemouth bass fishery was successfully protected from a reduction in quality size bass from initial heavy angling exploitation. Concurrently, bass length-weight relationships were unaffected. On a 4th lake, characterized by good recruitment and low forage levels, the proportion of quality did not increase and length-weight relationships remained undesirable.

Estimates of abundance, production, growth, survival, and mortality of largemouth bass were derived from spring electrofishing samples in the upper, middle, and lower sections of DeGray Lake from 1975 to 1979. Mean population estimates ranged from 86 to 163 bass per hectare; the populations were dominated by bass of ages I and IT (73% to 96%). Population estimates of the 3 coves based on surface area were biased because there were large differences in the ratio of shoreline length to surface area. Population estimates were adjusted to correct for this bias. Production was highest in the midlake section each year. Mean production estimates, based on spring electrofishing samples, ranged from 19.1 to 30.9 kg/ha. The greatest production of tissue and highest mortality occurred during the 2nd year of life. Harvest data indicated that 29.3% of the estimated spring standing crop of largemouth bass was taken by angling in 1977, and 26.8% in 1978.

Seasonal biomass estimates of largemouth bass (Micropterus salmoides), bluegill (Lepomis macrochirus ), and longear sunfish (L. megalotis ) were made during 3 growing seasons (1977 - 79) by cove rotenone sampling in May, June, August and September. Substantial mortality of young-of-the-year (YOY) largemouth bass during late summer suggests that this period was critical in determining year-class strength. Overwinter mortality was 88, 87, and 71%for the 1977-, 1978and 1979-year classes, respectively. Biomass of bluegill increased from May to August and decreased in September, probably as a result of predation. Biomass of longear sunfish was lowest in June and peaked in September in 2 of the 3 growing seasons. Longear sunfish seem to feed more in littoral areas than do bluegills, and are therefore probably more susceptible than bluegills to early summer predation by largemouth bass, and less susceptible than bluegills to late summer predation.

In pond predation studies, 4 total length (TL) groups (152 - 406 mm TL) of Florida largemouth bass (Micropterus salmoides floridaiu.Ls) were each provided 4 length groups (51 - 140 mm TL) of blue tilapia (Tilapia aurea) as forage. Estimated maximum length of tilapia that 38 - 500 mm TL bass can swallow ranged from 36 61% of the bass's total length. Bass <254 mm TL ate tilapia which approximated the maximum estimated length they could swallow. Bass >381 mm TL rarely ate tilapia >27% of their total length. Regression analysis of blue tilapia total length (mm) versus body depth (D; mm) was D = 0.322TL - 2.68 (r = 0.99). Due to the importance of the bass fIshery in Florida, the impact of blue tilapia may ultimately be judged largely on its value as bass prey.

From 1977 to 1979 largemouth bass (Micropterus salmoides) were collected in spring from Lake Higgins in North Carolina and tagged with Floy FD-67 internal anchor tags. Tagged fish were released back into the lake and a recapture effort was made the next year. During the year following tagging, tagged bass generally achieved a smaller length increment than untagged bass of a comparable size. Weights of tagged bass tended to be less than similar size untagged bass, but only in the 326- to 350-mm size interval was the difference significant (P < 0.05).

The North Carolina Largemouth Bass Catch Survey was initiated in 1975 to monitor angling success for largemouth bass (Micropterus salmoides) in the state's waters. The survey relies heavily on the participation of organized bass fishing clubs and reflects primarily tournament fishing results. Individual participants and clubs are asked to maintain catch records for each trip on a fishing log sheet. At the end of each month, the accumulated statistics are summarized by the participant and reported by body of water on preaddressed summary postcards. All materials are provided by the North Carolina Wildlife Resources Commission. The data are consolidated annually by body of water and season of year. The number of largemouth bass (TL ≥ 30 cm) caught per hour fished declined steadily in North Carolina reservoirs from 0.26 in 1977 to 0.18 in 1980. During the same period the catch rate in rivers and streams remained stable at between 0.23 and 0.25 fish per hour.

The largemouth bass(Micropterus salmoides) fishery in the Ocmulgee River, Georgia was studied to address concerns about overexploitation. A significant decline occurred over time in overall success, fished-for success, and average weight of largemouth bass in the creel. The annual exploitation rate was calculated to be 0.11 and was estimated in the year of low bass harvest. The annual survival rate was calculated to be 0.47. A Kolmogorov-Smirnov two sample test showed a significant decrease in the percent frequency of larger bass in electrofishing samples from fall 1976 to fall 1978. The high bass harvest from spring 1976 to fall 1977 is believed to be the primary cause of decline in the bass fishery. Low bass recruitment to harvestable size also contributed to the decline. Management strategies for enhancing the bass fishery include stocking of advanced fingerlings and better enforcement of the 305 mm size limit.

Water and benthic samples were collected quarterly, May 1980 to May 1981, from 21 sedimentation ponds on the Ollis Creek strip mine in Campbell County, Tennessee. Water samples in general were low in pH and high in sulfate, hardness, iron, and manganese. A total of 63 discernable chironomid taxa was collected and identified. Low pH ponds were generally dominated by Chironomus attenuatus and Tanytarsus, while higher pH ponds contained variable chironomid assemblages. Diversity values (richness) were significantly correlated with pH values. The polar ordination of chironomid assemblages showed a distinct linear arrangement of stressed ponds to those containing viable Centrarchid populations.

Postlarval and juvenile prawns (Macrobrachium rosenbergii) were exposed to 7 mirex concentrations plus control for 96 hours. Static acute toxicity tests were conducted at 28 C using deionized water reconstituted to hardnesses of 11, 42, 160 and 300 mg/l as CaC03 with postlarvae and 42 mg/l with juveniles. No statistical differences were observed in survivals of postlarvae or calculated median lethal mirex concentrations among hardnesses. A 96-hour LC50 for all postlarvae was 33.9 µg/l and for juveniles 900.8 µg/l mirex. Postlarvae and juveniles exposed to 1000 µg/l accumulated mirex up to 513X and 88X control levels. Mirex residues in juveniles were greater in nerve tissue than abdominal muscle or remaining carcass.

The status of the fish populations of 8 North Florida rivers and their relationships to major quality parameters were explored in an effort to better understand potential effects of man's activities. Of the 10 water quality parameters analyzed, only conductivity, total dissolved solids and total nitrogen were found to have significant predictive capabilities for the total fish population Rivers in the Florida Panhandle, which are low in nutrients, pH and organic carbon and high in turbidity, support a high biomass of rough fish, a moderate biomass of sport fish, and a low biomass of commercial and forage fishes; however, numerically, these rivers are dominated by forage fishes. The rivers of northern peninsular Florida generally have equally high biomasses of rough and sport fishes and low biomasses of commerical and forage fishes; however, sport fishes dominate these rivers numerically, comprising more than 70% of all fish encountered.

Various concentrations of dissolved oxygen were tested against normal embryonic development of striped bass, Morone saxatilis, eggs. Lowest level of dissolved oxygen necessary for normal development was established as 3.0 ppm. Abnormalities associated with suboptimal levels of dissolved oxygen are described, and the number for each concentration quantified.

Concentrations of chlorophyll a, soluble orthophosphate, dissolved nitrate and nitrite, and associated water quality parameters were measured biweekly from May 1979 to May 1980 in 3 sequential ponds located on a dairy farm. Pond number 1 was located in the immediate vicinity of the barn and feedlot, and demonstrated limnological characteristics of a sewage settling pond Chlorophyll a and soluble orthophosphate averaged 298 mg/m3 and 10.1 mg/l respectively. Dissolved oxygen in pond 1 averaged 3.4 mg/l at the surface but was never present at a depth of 1 m. The presence of a settling pond as the primary recipient of wastes produced by a herd of cattle resulted in downstream impoundments having limnological characteristics highly desirable for the culture of herbivorous fishes. Chlorophyll a in ponds 2 and 3 averaged 103 and 77 mg/m3 respectively. In contrast to pond 1, dissolved oxygen at the surface and 1 m in ponds 2 and 3 averaged 7.0 and 4.2, and 10.1 and 7.8 mg/l respectively.

When applied to ponds at equivalent rates, liquid fertilizer was much more effective than granular triple superphosphate in increasing futrable orthophate concentrations. Four methods of applying liquid fertilizers were tested: (1) liquid fertilizer was introduced into the intake side of a pump, mixed with water, and discharged into ponds, (2) a power sprayer was employed to spray the fertilizer over portions of pond surfaces, (3) a compression-type hand sprayer was used to spray fertilizer along shallow water edges of ponds, and (4) fertilizer was drained into the propeller wash of an outboard motor as the boat was driven back and forth over pond surfaces. All 4 methods proved effective. For 20 tests (5 for each method), filtrable orthophosphate concentrations averaged 0.02 mg/l before application and 0.29 mg/l 24-hr after treatment.

Six cages (1 m3 each) suspended in a Virginia pond were each stocked with 100 channel catfish (Ictalurus punctatus) fingerlings (127 mm TL, average) to evaluate 2 commercial fish feeds, each replicated 3 times. Both commercial diets were nutritionally complete and expanded 4-mm diameter pellets of comparable texture, color, and water stability. The daily feeding rate was 3% of biomass during the 124-day feeding period. Growth, net production, and feed utilization efficiencies with commercial trout feed were significantly greater than with commercial catfish cage feed. Survival was not influenced by diet type. The observed differences in catfish growth, production, and feed utilization efficiencies were primarily attributed to the higher levels of methionine, lysine, and metabolizable energy in the commercial trout feed.

Growth studies of channel catfish (Icatalurus punctatus) from 2 domestic and 2 wild strains were conducted in ponds. Growth rate, percent survival and size variability were evaluated. Domestic strains had higher growth rates than wild strains. There were no significant differences among strains for survival. Initial variations at stocking in length and weight among strains (as a function of time of spawning) were reduced during the growing season.

First generation inbred channel catfIsh (Ictalurus punctaius) were produced from full brother-sister matings to be compared in growth response to various temperature regimes to a control family produced from the same base population. Temperature regimes involved: (1) constant 22 C well water for 28 weeks, (2) well water heated to 27 C for 20 weeks and not heated (22 C) for the subsequent 8 weeks, and (3) ambient temperature of a 2-ha reservoir. Results indicated that genetic divergence between 2 lines was associated with a differential response to temperature regime. Weekly weight gain and total length growth were the highest in ambient temperature, intermediate in 27C, and least in 22 C temperature. Inbred catfIsh gained more than the controls in all 3 temperatures.

Bigmouth buffalo (Ictiobus cyprinellus) in 1.6-ha commercial channel catfish ponds fed entirely on zooplankton did not use demand feeders. Catfish ponds with buffalo stocked at 14 to 125 fish/ha had an average zooplankton density of 14 ml/m3 , as compared to 57 mlIm3 in catfish monoculture ponds. At a stocking rate of 500 buffalo/ha, 681 kg/ha of buffalo were produced in addition to the catfish crop.

Bigmouth buffalo (BM) (Ictiobus cyrinellus) X black buffalo (BL) (L niger) and BL X BM were compared with BM parentals when reared in polyculture with channel catfish (Ictalurus punctatus), grass carp (Ctenopharynogodon idella) , and largemouth bass (Micropterus salmoides) over a 2-season period. All buffalo were 1 year old when stocked and 2~ years of age at harvest. All other fish were yearlings when stocked. Stocking rates per hectare were 2500 catfish, 30 grass carp, 100 bass and 250 buffalo. At harvest, catfish averaged slightly over 1 kg each, while bigmouth, BL X BM, and BM X BL hybrids were 2.86, 2.93, and 2.14 kg, respectively. Grass carp averaged 3.33 kg each for all combinations. Highest catfish yields and greatest total fish production were achieved in the polyculture combinations. The polyculture stocking combination with bigmouth buffalo was best with BL X BM next. The monoculture yield was lowest, even when just catfish production was compared.

Abnormal characteristics studied were taillessness, triple-tailed, crookedback, albinism, and piebaldness in channel catfish (Ictalurus punctatus) and missing dorsal rm in blue tilapia (Tilapia aurea). Tailless catfish were divided into 2 groups: (1) totally tailless with the caudal rm completely missing and (2) partially tailless with the caudal rm reduced in size and modified in shape. Results indicated that the absence of the caudal rm in channel catfish severely reduced body weight and total length and should be selected against. Crooked back abnormality reduced body weight by 28 and 39% at 4 and 12 weeks of age, respectively. Triple-tailed catfish, however, were comparable in body weight to normal catfish at 4 and 12 weeks of age. Tailless, partially tailless, and normal catfish did not rank differently under different culture conditions indicating that multiple-environmental testing will not be required to determine relative growth of the 3 phenotypes.

Age and growth data pertaining to particular year-classes of largemouth bass (Micropterus salmoides), white crappie (Pomoxis annularis), bluegill sunfish (Lepomis macrochirus), white bass (Morone chrysops), gizzard shad (Dorosoma cepedianum), blue catfish (Ictalurus (urcatus) , and channel catfish (L punctatus) from particular Oklahoma impoundments were tested for consistency of backcalculations at particular annulus formations among sampling years. A compilation of the results showed that there were significant differences (a = 0.10), among what should have represented the same populations of scaly fish 69, 76, and 46% of the time for backcalculations at annulus I, annulus II, and annulus m, respectively. Significant differences among catfish data occurred 59 and 38% of the time at annulus I and annulus II, respectively.

The reproductive biology of chain pickerel in Lake Conway, Florida was studied from July 1976 to June 1977. The overall ratio of females to males was 1.1:1.0. Spawning apparently took place in shallow water among thick Vallisneria during a sharply dermed period from December to February. Average fecundity per female was 1232. Youngest fish to spawn were 2 years old.

Food of larval yellow perch (Perea flaveseens) from Keowee Reservoir, South Carolina was determined before (1973) and after (1976) power production began a 2,580-MW nuclear power plant Mean water temperatures at 1 m increased 2-3 C throughout the reservoir by 1976. The diet of larvae examined consisted exclusively of zooplankton. Cyclopoid copepods, Diapromus mississippiensis and Diaphanosoma braehyurum were the principal organisms eaten in all areas even though other organism were sometimes more abundant. The operation of the plant reduced zooplankton abundance in the discharge cove while the amount of zooplankton consumed by larval yellow perch increased.

Food items of 29 channel catfish (Ictalurus punctatus) collected during flooding of the Tombigbee River, Mississippi were almost exclusively composed of insects although other arthropods and in 1 case 2 rodents were eaten Terrestrial insects composed 84.7%, by weight, of the food eaten by catfish taken during floods compared to 1.2%, by weight, of the stomach contents of 15 catfish taken during normal flow conditions. Members of the orders Rodentia, Oligochaeta, Orthoptera and Trichoptera were the dominant foods, by weight, during flood conditions, contributing 64.4,6.1,6.0 and 5.8%, respectively. The stomach contents, by weight, of the catfish taken during normal flow were composed mainly of fish (51.0%), trichopterans (17.4%) and crayfish (12.9%).

Flathead catfish (Pylodictis olivaris) were introduced into the Cape Fear River in 1966 when 11 adult specimens weighing in a total of 107 kg were released near Fayetteville, North Carolina. The population has expanded from this initial release and now inhabits a 201·km section of the Cape Fear River. Growth rates of flathead catfish during this expansion phase has exceeded rates of riverine populations as previously reported by other investigators. Fishes were found to be the dominant forage consumed by flathead catfish as measured by frequency of occurrence, total numbers and total weight Species from the families Ictaluridae, Centrarchidae and Clupeidae were the most frequently utilized. A comparison was made of fish population samples taken prior to the introduction of flathead catfish with samples collected during this study.