Journal of the Southeastern Association of Fish and Wildlife Agencies

Of 109,675 striped bass (Morone saxatilis) stocked in June 1979 in Cherokee Reservoir, Tennessee, only 72 were recaptured. They were stocked at a mean total length of 3.5 cm and averaged 21.7 cm after I year of growth. After stocking, striped bass consumed mostly Crustacea, with Chironomidae being the primary food source for the rest of the year. Striped bass switched from invertebrates to fish (primarily Clupeidae) at 20 cm or approximately 1 year after stocking. Condition values (K) ranged from 0.8 to 1.3.

Several experiments were tried with varying results using 5 different marking techniques in an attempt to permanently mark juvenile striped bass (Marone saxatilis). Techniques included: immersion staining, dye injection, tetracycline ingestion, streamer tagging, and fin-clipping. From a practical and economical standpoint, 2 methods were satisfactory, at least for short term marking: fin-clipping and tetracycline ingestion. The latter method showed some promise of permanency in mark retention. Other methods were either too ephemeral, too expensive, or caused considerable mortality.

Physiochemical characteristics of Lake Frierson were monitored biweekly from 15 May to 14 September 1979. Lake Frierson revealed intense thermal stratification in late May. Stratification continued until fall turnover in mid-September. The anoxic hypolimnion started at the 3.0 to 3.5 m sampling depth and continued to the bottom. During this time, evaporation accounted for the loss of 1.0 m of water. Data from the shallow stations revealed anoxia and oxygen values of 2.0 mgll or less on 2 dates, 10 July and 8 August 1979.

An experimental pricing study using a Latin square design was conducted to determine the relative sales potential of fresh, pond-raised tilapia (Tilapia aurea) in supermarkets in north Alabama. Six prices ranging from $3.06/kg to $4.611kg were tested in 6 supermarkets during a 6-week period in September and October 1980. The effect of price on average sales of the sample of stores was estimated by simple linear regression. Sales potential varied from 4.11 to .97 kg liveweight! 1,000 customers over the price range, or approximately 617 to 146 kg/week for the 4 city study region. Retail prices which yielded maximum net revenue to the retailer and farmer were estimated to be $2.84/kg and $4.83/kg respectively.

Food habits of wild and hatchery-reared brook trout stocked in a stream environment were compared to those of blacknose dace within the same stream. Trout utilized aquatic adult insects (38.9%), terrestrial insects (19.5% ), and immature dipterans (14.2%) as their major food sources while dace consumed immature Trichoptera (27.0%) and Diptera (23.0%) as their major food items. A comparison of food habits suggested that some inter-specific competition might have been involved. Brook trout stomachs contained significantly more organisms than dace stomachs; however, no difference was found in mean volume of organisms in either.

Replacement of supplementary feeding with enhancement of natural productivity by pond fertilization for growout of the Gulf killifish (Fundulus grandis) was evaluated in 2 successive trials stocked at 330,000 fish/ha and 150,000 fish/ha, respectively. The first trial compared fertilization only, fertilization plus feeding at 3% body weight, and feeding at 3% body weight only in replicated 0.1 ha ponds. Growth rates were not significantly different, although days to marketable fish were 80-94 in the fertilized treatments and 100-107 in the fed-only ponds. Overall production averaged 710 kg/ha; 689 kg/ha in fertilized-only ponds. The second trial compared fertilization only, feeding at 5% body weight, and feeding at 5% body weight split into 2 daily feedings. Again growth rates did not significantly differ. Low fall temperatures prevented attainment of marketable fish. Both labor and material costs are substantially reduced by using fertilization only.

Winter growth of young-of-the-year bluegills (Lepomis macrochirus) and male bluegill X female green sunfish (L. cyanellus) hybrids was compared. After 112 days in ponds with a mean afternoon surface water temperature of 10.4 0 C, and under monospecies and bispecies culture conditions, the hybrids were significantly (P < 0.01) longer and heavier than the bluegiIls, outgrowing the bluegills by a ratio of approximately 2: 1.

Selection responses were compared in 4 lines of channel catfish (lctalurus punctatus) selected for: (1) large 40-week body weight (W+), (2) large spawn weight (S+), (3) sma1l40-week body weight and large spawn weight (W-S+), and (4) large 40-week body weight and small spawn weight (W+S-). Each line comprised 4 spawns hatched into 4 sibling sets. Ten randomly selected fish from each sibling set (40 fish per line) were included in the study and were grown in 2 segments of a recirculating raceway system. Results indicated that single-trait selection for 40-week body weight was most effective in increasing body weight and total length 9 and 28 months after selection was made. Joint selection for body weight and spawn weight (W+S-) was not as effective as selection for body weight alone (W+) on improving growth. Both lines were, however, more effective in growth improvement than S+ and W-S+ lines. Selection for increased spawn weight (S+ or W-S+) reduced subsequent growth severely.

Growth and food conversion patterns of Tilapia aurea raised in aquaria and fed diets containing 10% lipid from 4 different sources showed that growth and food conversion were significantly better on menhaden oil than on beef tallow. No significant differences were detected in growth of tilapia on catfish oil or soybean oil and either beef tallow or menhaden oil. No mortalities occurred during the course of the lO-week feeding trial. T. aurea responded similarly to channel catfish with respect to their ability to utilize menhaden oil as a suitable source of dietary lipid. Tilapia did not grow well on a diet supplemented with beef tallow, whereas channel catfish have been shown to perform equally well on both dietary lipids.

Defatted, glandless cottonseed flour and meal appear to be of relatively high nutritive value for fingerling channel catfish. Growth and feed conversions were not significantly different in fish fed diets in which glandless, defatted cottonseed flour or meal replaced varying amounts of solvent extracted soybean meal. Supplemental lysine did not significantly improve fish performance.

Average depths of 35 ponds were computed by reliable mapping techniques. Average depths were also estimated from maximum depths X 0.4, soundings made along several transects across ponds, and sounding made along a single S-pattern over ponds. Assuming that average depths by mapping were accurate, averages of relative errors by other procedures were: maximum depth X 0.4, 12.60/0; transects, 9%; and S-pattern, 5.4%. The S-pattern required fewer soundings and.was the most reliable. If mapping is not feasible, 12 to 24 soundings made along an S-pattern over a pond will provide a suitable value of average depth for computing pond volume.

Najas, Chara, and several filamentous algae species were controlled or eliminated by a single 0.1 mg!l (active ingredient) application of the herbicide Igran 80W, an 80% wettable powder formulation of terbutryn (2-tert-butylamino-4-ethyl-amino-6-methyl-thio-s-triazine), a commercial product registered for control of terrestrial vegetation but not now approved by the United States Environmental Protection Agency for use in ponds or other waters. The chemical, applied in summer, eliminated target plants within 2 weeks of application. The chemical is relatively nontoxic to fish at concentrations recommended for vegetation control.

Liquid ammonium polyphosphate fertilizer (Poly NR) was evaluated at state-owned public fishing lakes in Alabama. Initial evaluation indicated that only one-third the quantity of phosphate that would normally be applied in granular fertilizer (9 kg/ha P20 5 ) to fishing lakes was necessary to produce acceptable Secchi disc visibilities (≤ 60 cm) during the fertilization season. Further evaluation at 20 public fishing lakes demonstrated that significant financial savings could be achieved in conjunction with acceptable Secchi disc visibilities with a liquid fertilization program.

Rising costs and increasing demands for limited marine resources dictate that managers monitor the status and utilization of these resources efficiently. Seventy-two percent to 100% of aU weekend sport boat anglers completing a trip from 0700-1800 hours could be interviewed from 1000-1800 hours in Texas bay systems. A comparison of mean daily trailer boat counts suggest that optimum estimates of fishing pressure within a year can be made by stratifying data into 2 periods (13 November to 8 April; 9 April to 12 November).

The retention of Floy FD-68B anchor tags and survival of 200 tagged and fin-clipped white catfish (Ictalurus catus) and channel catfish (Ictalurus punctatus) were determined over a 184-day period in 2 0.20-ha ponds. In 1 pond, 50 tagged fish and 50 fin-clipped fish were stocked. In the second pond, 50 tagged and fin-clipped fish and 50 fin-clipped fish were stocked. Of the 70 tagged fish recovered (all tagged fish received 2 tags), all had retained at least 1 tag. Four Floy tags were lost, yielding an overall tag retention of 97.1 %. No separation of plastic sleeves was observed from the remaining 136 tags. Floy-tagged fish exhibited the highest rate of survival (86% ), followed by fin-clipped fish (66% ), then Floy-tagged and fin-clipped fish (54% ). The results indicated that use of Floy tags was less detrimental than removing a pectoral fin and spine from catfish.

Six hundred sixty fingerling largemouth bass (Micropterus salmoides) were stocked into a 0.1 ha hatchery pond for 69 days to determine if micromagnetic wire tags or the tagging process affected survival and growth rates. Two hundred twenty fingerlings were tagged internally in the vomerine (nasal) cartilage and 220 in the forebrain area. These were costocked with 220 control fingerlings. At recovery, survival rates of vomerine and forebrain tagged bass were comparable (70.5% and 75.9%), but were less than the rate for control fish (93.6%). Tag retention rates for vomerine and forebrain tagged fish (25.0% and 10.0%) were far less than desirable. Both vomerine and forebrain tagged fish (those retaining tags for 69 days) exhibited slower growth rates than controls, but only the forebraintagged fish grew significantly slower (P < 0.005).

Cost:benefit of 3 walleye fisheries were evaluated in 3 Texas reservoirs. Costs to establish walleye fisheries included expenses for equipment and for labor to procure and hatch eggs, to rear fry or fingerlings, and to stock reservoirs. Benefits of walleye fisheries were determined by multiplying the monetary value of a man-hour of recreational fishing by number of manhours of walleye fishing as determined by creel surveys. At Meredith Reservoir, where low densities of fry were stocked as the lake initially filled, costto- benefit of 1:89 was achieved in 3 years. At Greenbelt Reservoir, where fingerlings were stocked at low densities into an established fish community, it took 7 years to achieve a cost-to-benefit of only I :21. At White River, a reservoir which also had an established fish community, mass stocking (introducing large numbers of frys) achieved a cost-to-benefit of 1:42 in only 2 years.

Phytoplankton communities of commercial catfish ponds in westcentral Alabama were usually dominated by green algae (Chlorophyta). Blue-green algae, which were usually the dominant forms of algae in channel catfish ponds at the Auburn University Research Unit (east-central Alabama), were seldom present in great abundance in the commercial fish ponds. The pond waters in west-central Alabama had total alkalinity values of 69-148 mg/liter as CaC03 while total alkalinity values were much lower (lO to 15 mg/ liter) in pond waters on the Fisheries Research Unit. Difference in total alkalinity likely resulted in the difference in proportions of blue-green algae in ponds of the 2 vicinities.

Although mitigation is now required on excavation lakes resulting from limestone mining in South Florida, little baseline information exists on which to base mitigation recommendations. For this study, 8 representative limestone excavation lakes in Dade County, Florida, were sampled during 1981-82 to measure selected limnological parameters. There was little within-lake variation in water quality but substantial differences in means and ranges among lakes. Depths ranged from 3.2 to 15.2 m and surface areas, 8 to 44 ha. Maximum water temperature observed was 33° C and the minimum 19° C. Surface dissolved oxygen was 7.5-8.3 mglliter and 2.0- 7.5 mglliter at lake bottoms. Other ranges measured included alkalinity 72-170 mg/liter, conductivity 221 to 1,058 p,mhos, pH 7.2 to 8.2, and transparency 1.4 to 5.6 m. Mean values for total phosphorus (7.1 to 12.3 mg/m3 ) varied greatly by lake.

Age, growth, and sex ratio were determined from 484 yellow-phase American eels (Anguilla rostrata) collected from brackish waters (16.4 g/liter; mean salinity) in Charleston Harbor, South Carolina. Eels averaged 4.4 years, 437.6 mm total length, and 189.9 g live wet weight. Length-weight relationship was: log W = -5.7156 + 3.0067 log L. Length and weight increases were greatest in the third and fifth year of age, respectively. The population consisted of 85.5% mature females, 7.9% advanced females, and 6.6% males. Mature and advanced females averaged 1.6 and 3.1 years older than males (2.7 years), respectively. Males were consistently smaller than females for each age class.

Twenty-two larval fish taxa were collected from Wee Tee Lake, a backwater tributary of Santee River, South Carolina, and 2 adjacent main river sites during the spring of 1981 and 1982. Pomoxis spp., Alosa aestivalis, Dorosoma petenense, D. cepedianum, and Perca flavescens were the most abundant species collected in both Wee Tee Lake and Santee River during both years. These species were significantly (P < 0.05) more abundant in the lake than in the river, indicating a better spawning habitat in the lake. A. aestivalis and D. cepedianum appeared to spawn concurrently and exhibited similar patterns of diel periodicity. D. petenense spawned later and exhibited a different diel pattern. Flood control operations in the Santee River prior to the detection of larvae in 1982 appeared to alter time and duration of spawning and reduce species diversity and abundance of larval fish.

Suppression of largemouth bass (Micropterus salmoides floridanus) fingerling production in 0.01 ha ponds with high blue tilapia (Tilapia aurea) densities (760-1,900 kg/ha; 1,300-2,500 fish/ha) was studied to determine if the suppression is caused by direct competition for spawning sites. Bass spawned successfully in 8 of 9 ponds with tilapia but mean (x = 340) production of bass fingerlings was 84% less than in ponds without tilapia (x = 2183; N = 3). Difference in young-of-year bass production between ponds with and without tilapia was statistically significant; however, differences between young-of-year bass production in ponds with only male and only female tilapia were non-significant (P ≥ 0.05). Since only male blue tilapia construct spawning depressions, reduced bass fingerling production was attributed primarily to interactions independent of direct competition for spawning sites or tilapia sex.

Triploid hybrid grass carp (Ctenopharyngodon idella x Hypophthalmichthys nobilis) were provided known weights of hydrilla (Hydrilla verticillata) in 300 liter aquaria, to determine consumption rates for age I hybrids from 6 size groups, 21 to 37 cm total length (TL). Mean consumption rates for these groups at 26° C ranged from 25% to 52% of their body weight/day (% BW/D) or 1.7 to 8.6 g dry weight of hydrilla/day (g DW/ D). Smaller hybrids generally ate less hydrilla than larger fish, but expressed as a percentage of their body weight, small hybrids consumed more than large hybrids. The exception was the intermediate size hybrids (31 cm TL group), which consumed significantly (P < 0.05, Tukey's range test) more both in dry weight of hydrilla and in percent body weight than other groups. Regression of dry weight consumed/ day on total hybrid length produced the following equation: g DW/D =-6.1 + 0.039(TL); with a correlation coefficient of 0.82.

A minimum size limit of 305 mm for smallmouth bass (Micropterus dolomieui) in the Shenandoah River was evaluated by creel surveys to determine the limit's effect on the sport fishery. Smallmouth bass harvest decreased from 24/ha prior to the limit to an average of 6/ha after the limit. The catch and release fishery increased from 19/ha to 1111ha. Despite the restricted harvest, the number of legal bass (≥305 mm) harvested remained unchanged and average size decreased from 348 mm to 330 mm. Channel catfish (lctalurus punctatus) harvest decreased 91 %, but sunfish harvest increased more than 57%. Smallmouth bass growth rates were unchanged by the size limit, but annual mortality for ages III-V bass increased from 0.51 to 0.65. Increased mortality rate is thought to be the reason that bass harvest (≥305 mm) did not increase.

Analysis of catch records at state- owned and managed public fishing lakes indicated that significant increases in permit sales and harvest of fish occurred the year after treatment with rotenone to thin or eliminate threadfin shad and/ or gizzard shad. No significant change in the harvest of trophy largemouth bass was observed following treatment.