Journal of the Southeastern Association of Fish and Wildlife Agencies

Total dissolved gas, dissolved oxygen, dissolved nitrogen, pH, conductivity, temperature, and turbidity were monitored to determine diel and annual changes in a mariculture pond and in aquaria supplied with water discharged from a power plant. The diel and annual ranges of all hydrological parameters were greater in the pond than in aquaria. Diel patterns were similar in both cases but the amplitude was attenuated in the laboratory aquaria. Gas bubble disease (OBD) developed in 17 marine and estuarine fishes and in grass shrimps in the laboratory. GBD was more prevalent in aquaria at higher temperatures than in aquaria at lower temperatures. The disease occurred only in the winter months and was simultaneously found in fish in aquaria and in fish cultured in cages in the discharge canal.

Flow-through seawater bioassays of 28-days duration were conducted with the organochlorine pesticides heptachlor and toxaphene to detennine their toxicity to and bioconcentration by embryos and fry of the sheepshead minnow (Cyprinodon variegatus). At technical heptachlor measured concentrations of 4.3, 3.5, 2.2, 2.0, and 1.2 u/1 (ppb), test animal survival was 1, 5, 61, 79, and 88%, respectively. At toxaphene measured concentrations of 2.5, 1.1, 0.6, 0.3, and 0.2 1u/1, test animal survival was 10, 85, 79, 88, and 80% respectively. Average standard length of fry continuously exposed from fertilization to heptachlor concentrations of 4.3 and 3.5 1u/1 was significantly reduced (a; = 0.01). Concentration factors (concentration in fish/measured concentration in water) for heptachlor averaged 3,600 and for trans-chlordane averaged 8,600. Heptachlor epoxide and cis-chlordane were also present in the fish. Concentration factors for toxaphene in fry averaged 9,800.

This study was designed to compare the catch of sport and rough fishes and to determine the survival ofsport fishes captured by commercial gill nets in Texas reservoirs. Commercial fishermen were required to submit monthly reports for 1 yr (April, 1973 through March, 1974) on their rough fish harvest and on the number and species of sport fishes caught and released. The catch was recorded from monthly samples of commercial harvest on Lakes Sam Rayburn, Whitney, Somerville and B. A. Steinhagen and from quarterly samples on Lakes Livingston and Cedar Creek. Netting mortality of sport fishes was determined by holding the fish for 17 days following their capture. Data indicated commercial fishermen did not report their catch accurately. Mortality studies showed largemouth bass and crappie suffered almost total netting mortality; catfishes exhibited better survival 163-100%). Losses were small and apparently not harmful to the sport fish populations.

Primary productivity and nutrient concentrations were compared between the periphyton community on a freshwater artificial tire reef and the littoral phytoplankton in Smith Mountain Lake, Virginia, during the months of July, August, and September 1974. Primary productivity and nutrient concentration of the periphyton community were several times greater than that of the littoral phytoplankton. The periphyton community was dominated by pennate diatoms and filamentous green algae. Productivity measurements of the reef periphyton were on the same order of magnitude as the highest periphyton production rates reported in the literature. High Productivity of the tire reefperiphyton supports the hypothesis that freshwater artificial reefs support increased densities of fish and invertebrates by enhancing the productivity of aquatic environments.

To determine the effects of a large-scale rotenone renovation on a fish community and sport fishery, a 5-yr study was conducted on Sheldon Reservoir, a 485-ha Texas reservoir with small sport fish populations and poor fishing. The lake level was lowered and the remaining water treated with liquid rotenone. Gill nets, seines and a creel survey were used before and after treatment to evaluate this renovation. The relative abundance of sport fish populations increased from 17.54% (by weight) before treatment to a high of 46.27% after the renovation and restocking. Although high populations of sport fishes were maintained, turbid water conditions adversely affected fishing pressure and success, and prohibited accurate long-range evaluation of the effects of this treatment on the fishery. Cumulative cost/benefit ratios for the first 3 yr after renovation were 1:1.63, 1:1.20 and 1:0.93 consecutively.

The effectiveness and selectivity of monofilament and multifilament gill netting and area rotenone sampling in a shallow, 15.3-ha impoundment were determined. Estimates of species present, relative abundance, length-frequency distributions and standing crops were determined by the sampling techniques and compared with total fish populations estimated by rotenone treatment of the entire impoundment. Each sampling device furnished close approximations of species present and relative abundance of dominant fishes, but gill netting was the most economical method of determining these two statistics. Area rotenone sampling provided the only adequate length-frequency data. Rotenoning surveys misrepresented the overall standing crop of fishes, but apparently furnished accurate standing crop estimates for sections of the impoundment sampled.

The use of fin-clips and dart tags for detennining recovery efficiency in summer cove rotenone samples was compared. Using a standardized cove sampling methodology, fin-clipped fish were recovered from 69 coves at an overall rate (%) of 52.4 ± 4.7 (2 S. E.), while in 21 coves 73.6 ± 3.0% of the dart-tagged fish were recovered. As the sample season progressed recovery efficiencies for fin-clipped fish showed a consistent improvement, however, neither seasonal nor year-to-year means was as high as dart-tagged estimates. End of season values with both marking methods showed a recovery efficiency of about 70 percent in the reservoirs surveyed.

The perfection of culture techniques for the channel catfish (Ictalurus punctatus) has been aided by the commercial demand for fingerlings, by the fact that the catfish is "precocial" by the time the yolk sac is absorbed, is not cannibalistic, and readily utilizes artificial feeds early in life. Several techniques have been developed for producing catfish fingerlings, but the method that appears most acceptable for the production of large numbers of fingerlings is by the pond spawning/trough incubation technique. The principal advantages of this method are that it makes possible a high survival of fingerlings and control ofdensity in the rearing ponds. Where it is desired to mate selected individuals, the aquarium method or the pen method are particularly attractive. There is interest in tank rearing of fingerlings; however, due to the characteristics of the channel catfish, the authors question that this method will have any advantage over the pond method.

Stocking of small fingerling catfish into rearing ponds at a density to give the optimum number and weight for harvest at edible size gives a low gain per acre per day during the first half of the grow-out period. Use of a much heavier stocking rate initially, with periodic division or splitting of the stock shows promise of significantly increasing the gain per acre per day. Use of two divisions gave a gain per acre per day ofabout 25 pounds for the first phase and 10 pounds for the second. A hypothetical example is presented which should make a gain of 12 pounds per acre per day possible over a 360 day calendar year period under central Alabama conditions. Several possible ways the growing stock could be divided are listed.

A telephone and personal survey of all known Arkansas fish producers was made during the first quarter of1976 to determine the extent of change in aquaculture production during the past three years. The survey indicated that although intensive pond production has been reduced by about 4,050 hectares, the economic value since 1972, because of higher prices received for the products, has increased by 16.8% to $24,191,700. Growth in the industry has slowed in recent years due to narrowing profit margins and changes in prices and allotments for other agricultural crops.

Cultural technology is adequate to produce crawfish in ponds with water quality a main consideration. Occurrence of small stunted crawfish has been reduced by increasing trapping frequency. A mechanized harvester and more efficient traps and bait are needed to relieve labor problems. The processing industry must have a mechanical peeler and utilize traditional shrimp freezing technology to extend shelf life and markets. Marketing is a key to sustained pond production. Prices of crawfish will increase as processors and live market sales compete for the raw product. Expansion of the market for both imports and exports will be on a national and intemational scale.

A total of 710 largemouth bass was collected from a 4047 ha coastal freshwater marsh in Southwestern Louisiana. Seven age-groups (()-VII) were present in the marsh. Annual increments were smaller for the first 3 years of life when compared to other Louisiana areas, but greater during the remainder of life. Condition factors were comparable to those obtained by other Louisiana authors. Food habits of young of-the-year bass >95 mm in length were not different from age groups I and II. Fish and adult odonates were the principal forage for bass in the summer. During the winter, stomachs of bass from age groups ()II contained principally fish and freshwater shrimp whereas those from age groups ≥III contained predominantly fish.

Epistylis infections were found on 16 fish species in the Yadkin and Catawba River reservoirs in North Carolina during 1974-75. Families most affected were Ictaluridae, Percichthyidae, and Centrarchidae. Highest incidence of the disease occurred during the summer and fall months. The most common infection site among most species of fishes was inside the mouth. A positive correlation was found between total fish length and Epistylis infection rate among Lepomis auritus, Lepomis macrochirus, and Micropterus salmoides. The bacterium, Aeromonas hydrophila, often was isolated from Epistylisinfected fishes and was believed responsible for two large fish kills.

The occurrences of the 20 most abundant fish species in impoundments of each of seven rivers were compared using Long's (1963) index of faunal resemblance. Higher order systems, i.e., larger rivers, contain more species than smaller rivers. Also, impoundments of larger river systems tend to be more similar, while those on smaller rivers maintain their unique faunal assemblages.

Trout stream management consists of protection of existing waters from further degradation, and management of the fishery through regulation implementation and stocking programs to manipulate use patterns. The dwindling trout resource is impacted by an increasing number of resource users. Management ofa trout fishery should consider attitudes of trout fishermen expressed in their definitions of quality angling. An area-wide program should be managed to provide a variety ofangling experiences. Regulations and stocking programs are essential management tools to manipulate use patterns to protect the resource and at the same time provide for the desires of trout fishermen.

Data from five northeast Georgia trout streams revealed significant alteration of ambient temperatures by impoundments. A 7.3 ha impoundment releasing water at 3.9 m warmed Anderson Creek a mean 2.2 C during August 1973 and reduced diurnal temperature variation by two-thirds. Surfacerelease impoundments on Bean Creek and Chickamauga Creek warmed ambient temperatures a mean 4.2 C and 3.8 C, respectively, dUring the summer of 1974. Diurnal fluctuations were increased in these two streams. A 21 ha surface release impoundment on Smith Creek warmed ambient stream temperatures a mean 3.6 C during the summer of1973 in spite of efforts to release water through the drain valve at 18 m below the surface. A multi-level release structure on Taylor Creek designed to closely duplicate ambient mean daily temperatures was not properly adjusted and elevated temperatures a mean 4.3 C during a three month period.

The seasonal distribution of larval fish in the Cumberland River was studied in 1974 and 1975 as part of an environmental monitoring program at the site of the proposed Hartsville Nuclear Power Plant near Dixon Springs, Tennessee. Meter and half-meter diameter nets were used to collect 13,571 larval or young juvenile fish of 13 families during evening hours from April to mid-August. Clupeids, catostomids and Lepomis sp. dominated the collections during both years. Concentrations of larval fish were significantly IP≤ 0.05) higher in the Dixon Creek backwater area than in the river proper. Equations were developed by stepwise multiple regression to predict the seasonal abundance of major taxa and total larval fish populations by water temperature and discharge correlations.

From July, 1974, through July, 1975 the movements of 29 walleye were monitored in Center Hill Reservoir, Tennessee, using ultrasonic telemetric techniques. Seasonally, monitored walleye were most active during the winter and least active during the summer and activity was not correlated with angler success. Diel activity varied from a nocturnal pattern during the summer, to crepuscular during the fall and winter, and no pattern was evident during the spring. Temperature preference was a range of 12°18° C and the only bathymetric pattern established was that of a preference for the bottom, regardless of depth. However, oxygen was often limiting in the hypolimnetic zone. No patterns were established when the daily rates ofmovement of walleye were correlated with various environmental variables. Monitored walleye preferred to remain more than 30 meters offshore during all seasons of the year. Also preferences for certain type areas of the reservoir and bottoms were evident.

Two natural ponds were studied to investigate the effects of introduced grass carp on native fishes. Biologically significant deleterious effects were detennined for both fish populations. Largemouth bass populations were reduced in one pond and substantially altered at the second site. Fish population structures shifted and symptoms of overcrowding were evident. Bluegill numbers increased in both ponds. Warmouth were greatly reduced in one pond. Several species offorage fishes were eliminated.

A propeller pump was operated for 120 days on a lake of40 ha surface area in north-central Oklahoma in the summer of 1975 to accomplish artificial destratification. The pump created a downf/ow of welloxygenated surface water by means ofa 1.82 m diameter propeller located 1.8 m below the lake's surface. The pump produced a flow of 1.72 m3/sec, equivalent to 12.9% of total lake volume per day, at 17 rpm with a 1.0 h.p. electric motor. Four days of pumping eliminated thermal stratification, it raised the temperature of the hypolimnetic water 9.5C, but increased surface temperature less than re. Thereafter the entire water column remained isothermal (27-29°C) during the summer. Dissolved oxygen at 5 m increased from 0.2 to 4.3 mg/ after the first day of pumping; thereafter DO levels at 5 and 9 m depths were above levels observed in 1973 and 1974; in mid-July 100% of the lake's volume contained more than 5 mg/l DO.

Food habits of the coastal marsh raccoon, Procyon lotor megalodous Lowery, in Louisiana were studied from June 1973 to August 1974. The raccoon's role as predator of the eggs and hatchlings of the American alligator, Alligator mississippiensis, was also evaluated. Eight hundred and sixty-six raccoon scats were collected from the fresh, intermediate and brackish marsh types, an average of 24 scats per month per habitat type. Crustaceans (crawfish, fiddler crabs (Uca spp.), blue crabs (Callinectes sapidus) were the major food item consumed and comprised 49 percent of the yearly diets of raccoons. Fruits were important fall foods. Although not utilized in great quantities, insects were also important, particularly during periods ofprolonged marsh flooding. A marked difference occurred between years in the incidence of raccoon predation on alligator nests ranging from no predation in the 1973 nesting season to 45 percent in 1974.

Accounts of reported alligator attacks in Florida are summarized and examined for evidence of patterns that might explain the causes ofalligator attacks. Twenty-two such incidents were found. Three were provoked, circumstances surrounding 3 were unclear, and the other 16 appeared to be unprovoked attacks. Attacks occurred during the warmer months, usually during late afternoon. Most victims were Florida residents between 9 and 16 years old, most were standing in water or swimming, and none were feeding the alligators at the time ofattack. All except one victim were unaware of the alligator's presence at the time of the attack.

A telemetric study was conducted on immature alligators (Alligator mississippiensis) in two north Louisiana lakes, Black Bayou Lake and Wham Brake Reservoir, from 10 April, 1975, through 4 December, 1975. Twenty-three alligators, 11 native and 12 introduced from a coastal marsh habitat were fitted with color-coded neck-collar radio transmitters and their daily movements followed with a directional receiver. Minimum home range sizes varied from 0.8 to 321 hectares for all animals with no significant difference being found between range sizes oflocal and introduced alligators.

A literature review revealed that little data-based information on the breeding potential of the wild turkey (Meleagris gallopavo) is available. A nine-year study in which the emphasis was on nesting attempted to supply some of this information. We observed 155 nests and found that most hens, including yearlings, attempted to nest each spring and most adult hens renested if they lost their first clutch early in incubation. Clutch sizes and hatchability were not greatly different in first and second nests or between age classes, but yearling hens did not as often attempt to renest as did adults. The incubation period was less than 27 days. It is concluded that the breeding potential of the wild turkey. in respect to laying, is probably greater than generally supposed.