Journal of the Southeastern Association of Fish and Wildlife Agencies

During the 1974 spawning season in Tennessee. 17 female striped bass were injected with chorionic gonadotropin and placed in circular tanks to spawn. One or more males, also injected with gonadotropin. were placed in 13 of the tanks with each female. In four of the tanks, treated white bass males (M. chrysops) were added in an attempt to produce hybrids. All 13 of the females, where there were no white bass, successfully spawned producing an estimated 19.3 million eggs. More than 11 million fry hatched. The four females in tanks containing white bass males ripened but had to be manually stripped. The tank spawning method requires considerably less handling and imposes much less stress on brood fish than the conventional hormone technique.

The increasing demand for striped bass fingerlings has established a need for improved pond culture techniques for this species. Standard guidelines were developed from methods in use at several production hatcheries. These along with improvements after two production seasons are described.

A brief history of developments with Morone hybrids is given. Two of these fishes have shown potential as a supplemental sport fish for fresh water lakes and reservoirs. The original hybrid. white bass male X striped bass female. has provided substantial fisheries in the Southeast. Compared to striped bass, greater returns to sport fishermen, faster early growth. and higher survival has been documented. The threat of backcross deformities appears minimal at this time. The reciprocal hybrid, striped bass male X white bass female. was successfully cultured in 1973. Early findings have been encouraging, but data is incomplete for conclusive evaluation. First year growth varied between 12 and 14 inches, while average weights were higher than for striped bass of similar sizes. In general appearance, this hybrid resembles white bass. Life history aspects and culture methods for hybrid production are discussed.

Striped bass have been introduced into many inland waters of the southeastern states in an effort to establish a fishery, and to provide a biological control for clupeoid fishes. The Striped Bass Committee of the Southern Division, American Fisheries Society compiled information on the success of past introductions in 1970 and again in 1973. The information collected by the Committee is used to illustrate the successes and failures of introductions of fry, fingerlings, and adult fishes. Variables, other than size of fish at the time of stocking, were tabulated and analyzed to determine their significance in the success of introductions.

One million acres of water in inland reservoirs currently contain fishable populations of striped bass. Fingerling production in 1974 was in excessof 10.5 million fish and this equals the total fingerling introductions between 1965 and 1973. Major efforts are in progress in estuaries to reestablish striped bass populations and to mitigate losses of fish due to power plant operation. Improved fertilization techniques in ponds should serve to increase fingerling production in the future. The use of hybrids is slowly gaining favor, both in reservoirs and in small impoundments. Reservoir management of striped bass suffers from the lack of quantification of fingerling survival and of the effects of the fish upon the forage base and upon the creel.

A three-day fishing tournament on the 51. Johns River, Florida, in which 200 fishermen competed. yielded 1165 largemouth bass over 12 inches, and 1254 bass smaller than 12 inches. The over-aU catch rate was 0.50 bass per hour. The catch per acre of water fished was 0.03 bass. Over-all mortality estimates ranged from 22.3 to 43.8 percent; they were due primarily to epidermal bacterial and fungal infections, contracted by handling. The 3 I-day tag retention rate for largemouth bass tagged with the Floy FD-68-B anchor tag was found to be S1.1 percent for fish held in a hatchery pond.

A study of two bass tournaments was undertaken on Lakes Sam Rayburn and Toledo Bend in March, 1974 to evaluate a "Don't Kill Your Catch" program initiated by the Bass Anglers Sportsmen's Society, Mortality offish held in live-wells or water tanks up to the point and just after "weigh-in" was determined. Delayed mortality was measured by taking a sample from the tournamentcaught bass and stocking them in hatchery ponds for 28 days. A treatment of Terramycin was given loa portion of these hatcheryheld fish to evaluate its use for improving survival of the fish. Tolal mortality of fish taken in both tournaments was considered low (32 per cent of the harvested fish). Tournament fish stocked in hatchery ponds and treated with Terramycin had similar survival rates to those of stocked untreated fishes.

Oxytetracycline, as a prophylaxis against secondary bacterial infections, was injected into 531 largemouth bass (Micropterus salmaides) which were caught during a fishing tournament on Lake Seminole, Georgia. The injected fish, along with 531 control bass, were held for observation in a 1-acre canal contiguous with the lake. After 19 days, 4.3% of the injected fish had died and 2.2% of the control fish had died. The oxytetracycline was not beneficial in reducing mortality in the released bass.

Tournament-caught largemouth bass were compared with hatchery bass to determine survival rates of bass injected or uninjected with oxytetracycline. Significant mortality rates occurred only in injected tournament-caught bass held in plastic pools. Hatchery controls, uninjected tournament bass and injected tournament bass held in hatchery ponds exhibited mortality rates similar to each other. Survival was best in hatchery ponds, but not significantly better than in pools except for injected tournament-caught bass.

A 1972 survey was taken of Texas bass clubs todetennine the number and location of organizations. their membership, club objectives, tournament regulations, fishing success and estimated harvest of bass from Texas reservoirs. Questionnaires were sent to 206 clubs, and reports were received from 170 of the groups during this study. The 170 reporting organizations collectively held 1,755 tournaments in 1972. Harvest records revealed an average catch per unit effort of 0.17 bass and/ OT O.28tb. per man-hour. Harvest from tournament lakes was, in most cases, less than 0.50 lb. per acre and was not considered harmful to bass populations at this time.

The results from the use of antimycin A in Georgia fish ponds as a fish toxicant within the period 1968-1974 are presented in the following paper. Concentrations of antimycin at 0.4 to 0.6 parts per billion (ppb) were found to be the most desirable range for reducing populations of scalefish in attempting to improve balance and/ or to improve fishing. For controlling all sizes of scalefish in catfish ponds, concentrations of 2.0 and 4.0 ppb seemed effective. The gravity flow method of application by boat was found to be adequate, but other means of application could be used successfully.

Applications of 1.5 mg/l ofThanite were made in a 0.68-hectare hard-water pond and a 3.64-hectare soft-water pond in Florida. The 19 species of fishes collected alive represented the following families: Lepisosteidae; Anguillidae; Esocidae; Cyprinidae; Catostomidae; Ictaluridae; Aphredoderidae: Cyprinodontidae; Poeciliidae; Atherinidae; and Centrarchidae. The treatment was not effective for collecting bowfin (Amia calva), yellow bullheads (lelulurus natalis), or brown bullheads (I. nebulosus). Thanite eliminated all but 20 fish (0.4 percent) in the small pond and 100 (1.4 percent) in the large pond.

Thanite (82% isobornyl thiocyanoacetate) has been used as a fish management tool on International Paper Company's Southlands Experiment Forest since 1968. Annually, Experiment Forest personnel successfully move 2.000 to 4,000 largemouth bass (Micropterus sa/moides) with an 0.8 to I ppm (active ingredient) mixture of 80%Thanite - 20% Atlox 1045-A. Collection and survival percentages are higher when water temperatures are less than 70°F. Collected fish are placed in cans of untreated water in collection boats and later transferred to an aerated holding tank. Recovery in the tank is usually rapid and survival exceeds 90%.

An extreme drawdown conducted on Lake Tohopekaliga, Florida. improved littoral substrate. stimulated development of aquatic macrophytes and increased invertebrate standing crop. Benthic macroinvertebrates increased from 98 to 244 organisms per square foot in limnetic areas after reflooding; littoral benthos rose from 154 to 250 organisms per square foot. Phytomacrofauna increased from a predrawdown high of304. to 1364 organisms per sample unit after reflooding, Standing crops decreased to predrawdown estimates within two years following peak production periods. These decreases were attributed mainly to predator cropping. Fish food organisms were favored by the drawdown, and their incidence in largemouth bass stomachs increased. As a final expression of increased production. sportfish populations which utilized these organisms nearly doubled.

An extreme drawdown conducted on Lake Tohopekaliga rejuvenated littoral substrate, stimulated development of desirable aquatic plants and increased macroinvertebrate production. As a result of these beneficial changes standing crops offish in littoral areas increased from a high of 191 pounds per acre before the drawdown to 455 pounds per acre within two years after reflooding. Limnetic standing crops increased from 59 pounds per acre to 127 pounds per acre during the same period. Biomass of sportfish neady doubled, although forage fish accounted for a higher percentage of the population fonowing reflooding.lndividual species response to the drawdown varied. Numbers of harvestable size sportfish increased following reflooding. The monetary value of the Lake Tohopekaliga fishery increased by 37 percent, or $6,222,186.

A 15-month study of a natural tidal pass on the southeastern Louisiana coast revealed that the pass and adjacent inshore waters are utilized by a variety of immature fishes as immigration pathway and! or nursery. Eighty species representing 39 families were found to occur in the pass area, including young of several commercial and sport fishes. Two seasonal assemblages of immature fishes were identified, cold- and warmwater. Coldwater species were mostly immigrating young of offshore spawners, while warmwater spec'es were mostly young of inshore spawners. The catch of coldwater species was lnfluenced more by tidal stages than light periods; warmwater species exhibited varied diel catch patterns but the catch of predominant warmwater species was more closely associated with light periods than tidal stages. The similarity in diel patterns exhibited by some of the coldwater assemblage indicates that this group may react similarly to the problem of inshore transport (immigration).

A long-haul seine was designed to sample 10,000 m2 of open water less than 3.5 m deep for both pelagic and semi-demersal fish populations. The net, 354 m long constructed of 20 and 25 mm bar mesh. was used to encircle the area, and by a simple method to concentrate and purse the catch in open water. Atlantic menhaden, Brevoortia tyrannus; Atlantic thread herring, Opisthonema oglinum; pinfish, Lagodon rhomboides; and striped mullet, MugU cephalus were the most abundant species collected from 60 samples taken during 1973 in the Newport River estuary (Carteret County, North Carolina). Sample to sample variation for individual species was high, with coefficients of variation usually about 100%. Mark-recapture experiments using a total of 232 marked fish indicated that 31 to 54% (95% confidence limits) of the marked pelagic and semi-demersal fish released in the sampled water mass were recovered.

Tests were conducted to determine (1) the acute (96-hour) toxicity of hexachlofobenzene (HCD) to pink shrimp (Penaeus duorarum), grass shrimp (Palaemonetes pugio), sheepshead minnows (Cyprinodon variegalus) and pinfish (lAgodon rhomboides) and (2) the rate of HCD uptake and depuration by pinfish. Hexachlorobenzene was not acutely toxic to any of the animals tested at measured concentrations in sea water to 25 ug/1. However, both species of shrimps in the highest HeB concentration were lethargic as compared to controls and exhibited an uncharacteristically white hepatopancreas at the end of the 96-hour exposure. Pinfish exposed to average measured HCB concentrations of 0.06, 0.15, 0.65, 1.87, or 5.2 ug/1 for 42 days accumulated the compound throughout the exposure. Maximum residue in muscle (wet-weight) was 34,000X the measured concentration in test water. Pinfish retained most (>50%) of the HCB after a 28-day depuration period in HCB-free water.

Acute (96-hour) bioassays were performed with endrin and the following estuarine organisms: American oyster (Crassostrea virginica), pink shrimp (Penaeus duorarum), grass shrimp (Palaemanete's pugio). sailfin molly (Poecilia latipinna) and sheepshead minnow (Cyprinodon variegatus). Endrin was acutely toxic to all organisms tested, except oysters, whose shell growth was appreciably inhibited by 56 ug/1 (parts per billion) of the chemical. Pink shrimp were the most sensitive animal tested, but significant numbers of both species of shrimps and fishes died when exposed 10 concentrations of one ug/1 or less, In a separate test, embryos and fry of the sheepshead minnow were exposed to concentrations of endrin ranging from 0.046 to 1.0 ug/1 (nominal) for 33 days in an intermittant-flow bioassay. Embryos were not affected by the concentrations to which they were exposed, but the estimated LC50 (prohit analysis. a=.05) of fry was 0.27 ug/1.

An investigation of the effect of two feeding rates on pond production of advanced fingerling striped bass was studied at the Auburn University Fisheries Research Unit from June 27 to November 24,1972. The mean survival for fingerlings fed a high feeding rate was 71.87% as opposed to 70.13% for fingerlings fed a low feeding rate. Mean production for fingerlings fed a high and low feeding rate was 266.44 kg/ha and 293.68 kg/ha. respectively. Food conversion for fingerlings fed a high feeding rate was 3.74 as compared to 2.51 for fingerlings fed a low feeding rate.

The effects of increased water hardness. salinity. and source of fry on the survival and growth of striped bass fry from three females from the Cooper River, South Carolina. and two females from the Savannah River. Georgia. were studied at the Fisheries Research Unit. Auburn University, from 6 April to 11 June. 1971. Fry were stocked in one ofthree water treatments: control with a total hardness of 30 to 40 ppm; added hardness. 125 to 175 ppm; and added salinity, (chlorides) 1,100 to 1,500 ppm. Variance tests for homogeneity and contingency tables were employed for data analysis. Survival of striped bass fry was increased in the added salinity treatment. Fry survival in the control and added hardness treatments appeared to be dependent on the fry groups rather than the effects of the treatments. The survival of Cooper River fry appeared to be more variable in water with added hardness; Savannah River fry survival was more variable in the control treatment.

The use of suitably constructed and located stock water ponds for food fish culture is recommended, based upon investigation into the possibilities of these small bodies of water to rear a channel catfish-largemouth bass combination. Stocked with 2,000 catfish and 100 bass per acre with supplemental feeding, two, two-year production cycles showed the following results: total fish production, 2,634 and 3,791 pounds per acre; feed conversion, 2.5 and 2.4; recovery of stocked catfish, 84 and 91 percent; recovery of stocked bass, 40 and 50 percent. In addition to supplying food fish, the pond provided recreation through the fish cultural activity and by hook and line fishing.

Channel catfish were stocked in 27, 1/10-acre ponds at the rate of 3,000 per acre and fed nine commercial-type rations containing three protein percentages and three levels of fish meal for 200 days. Average survival for the experiment was 96.8% and 93% of the fish were over 12 inches in length at harvest. Average yield for treatments ranged from 2,330 to 3,030 Ib/acre and the average for all treatments was 2,638 lb. The results indicated that satisfactory production can be obtained with all-plant rations. The 29%. all-plant protein diet yielded 2,330 Ib/ acre of harvestable size fish. Increasing total protein in the all-plant rations to 36 and 43% resulted in production of 2,475 and 2,640 lb/acre, respectively. Replacing 1/6 of the plant protein with fish meal protein, at the 29 per cent protein level, increased production by 100 Ib/acre; however, replacing 1/3 of plant protein with fish meal protein yielded an increase of 430 lb.

Pupae of face fly (Musca autumnalis De Geer) were offered to channel catfish flngerlings fed outdoors in plastic pools. Other channel catfish fingerlings received rations of equal parts of face fly pupae and Purina Catfish Cage Chow (pellets) or pellets only. After 9 weeks of feeding, catfish from each pool were counted and weighed. Survival rates were 94. 97. and 93% and ratios of dry weight of food to increase in live weight of fish were 1.62, 1.77. and 2.29 for fish receiving pupae, pupae and pellets mixed, and pellets only, respectively. There were no statistically significant differences between these values (P=.05).