Journal of the Southeastern Association of Fish and Wildlife Agencies

Due to a combination of factors, Lake Catherine, a 3,000 - acre reservoir which had never known a vegetation problem, suddenly became congested with rooted aquatic vegetation in 1960. The vegetation, mostly coontail, Ceratophyllum demersum,and Elodea sp., could be controlled with chemicals and consequently various chemicals were used by the riparian property owners on small localized areas. However, for the larger, main body of the lake, chemical herbicides were considered too expensive to be practical. In October 1960 the Arkansas Game and Fish Commission was petitioned both by the sportsmen in the area, the riparian property owners, and the Arkansas Power and Light Company (owners of the dam and reservoir), to advance a plan for the control of the vegetation. The formulation and the carrying out of that plan is discussed, with emphasis on the combination of two biological methods of control

Due to a combination of factors, Lake Catherine, a 3,000 - acre reservoir which had never known a vegetation problem, suddenly became congested with rooted aquatic vegetation in 1960. The vegetation, mostly coontail, Ceratophyllum demersum,and Elodea sp., could be controlled with chemicals and consequently various chemicals were used by the riparian property owners on small localized areas. However, for the larger, main body of the lake, chemical herbicides were considered too expensive to be practical. In October 1960 the Arkansas Game and Fish Commission was petitioned both by the sportsmen in the area, the riparian property owners, and the Arkansas Power and Light Company (owners of the dam and reservoir), to advance a plan for the control of the vegetation. The formulation and the carrying out of that plan is discussed, with emphasis on the combination of two biological methods of control.

Due to a combination of factors, Lake Catherine, a 3,000 - acre reservoir which had never known a vegetation problem, suddenly became congested with rooted aquatic vegetation in 1960. The vegetation, mostly coontail, Ceratophyllum demersum,and Elodea sp., could be controlled with chemicals and consequently various chemicals were used by the riparian property owners on small localized areas. However, for the larger, main body of the lake, chemical herbicides were considered too expensive to be practical. In October 1960 the Arkansas Game and Fish Commission was petitioned both by the sportsmen in the area, the riparian property owners, and the Arkansas Power and Light Company (owners of the dam and reservoir), to advance a plan for the control of the vegetation. The formulation and the carrying out of that plan is discussed, with emphasis on the combination of two biological methods of control.

The growth rate data indicated that diets containing casein and the protein combination produced approximately equal growth and that both of these protein sources produced better growth than soybean protein alone. Fish receiving diets containing 30 per cent protein gained at a significantly higher rate than fish receiving diets containing five per cent protein. The relative order of growth rates for the three sources of protein was the same at both levels of protein in the diet.

Cultural practices which either contribute nutrient materials to the ecosystem or accelerate detrition by induced recirculation of nutrients within the system result in environmental changes which persist after the practices have been discontinued. The effects of environmental modification were found to be reflected in species structure of native fish populations. The percent of centrarchids within the total population was found to occur in direct proportion to the percent of productive bottom. Macroinvertebrate organisms used as food by centrarchids were' found to be restricted to certain bottom types. These studies confirm the conclusion of Eggleton (1933) that forces inherent in the substratum itself bend and shape all other forces and thus condition the reaction of both plants and animals. The role of submersed and floating vegetation as a substrate for invertebrate organisms is discussed.

The use of an aluminum boat as the electrode on streams and rivers is quite simple and is as effective as the electrodes suspended from the side of a boat. This eliminates the need of any electrodes hanging over the side of the boat and allows the operator to work efficiently through trash and submerged obstaeles. It is necessary, if using direct current or pulsed direct current, to connect the negative lead to the aluminum hull of the boat instead of to the electrodes suspended on each side. The individual items required and their use in this operation, e.g., variable voltage pulsating unit, modified negative and positive electrodes and others, are described. The eost of the unit, including boat, motor, trailer, variable voltage pulsator, miscellaneous and safety items, is approximately $2,000.00. Safety items are listed and described to assist in eliminating shock hazards.

The number of largemouth bass (Micropterus salmoides) in a 3.5-acre experimenbal pond located at Auburn University Agricultural Experiment Station was estimated by mark and recovery techniques using both Schnabel and Peterson methods. Sampling was done wirth both electric shocker and angling. Estimates were made during two periods in 1962. Various estimates of the number of bass made in this study were fairly uniform. However, on draining the estimates were found to be in error by approximately 50 percent. Based on number of bass recovered at draining and the computed percentage of survival, the value of N for the first period (May 23, to December 20, 1962), was computed to be 604 bass, whereas the Schnabel and Peterson methods gave N values of 304 bass and 469 bass with percent errors of -49.7 and -22.4, respectively. The theoretical requirements of both methods seemed to be met for the first period.

Plate samplers constructed of VB-inch thick masonite were used in a bioassay study of water quality in the Black Warrior River near Tuscaloosa, Alabama. The samplers were placed in a fertilized pond and allowed to accumulate a dense population of larval chironomids (Chironomidae) for one month. The samplers were then placed into the river at stations above the outfall of the uppermost industry and below each outfall of four industries. Counts of chironomids on each of the samplers were made after one week and comp.arisons were made between the average number of organisms on the samplers at stations above the outfalls and the average number at each of the stations downstream from the outfalls. It appeared that this inexpensive technique of bioassay can be useful in determining the effects of pollution on chironomids. Today there are more people with more leisure time demanding more clean freshwater for recreation than ever before.

One thousand three hundred and forty-six largemouth bass were captured, tagged, and released in nineteen bodies of water throughout the State of Florida. Spaghetti, Petersen disc, and Monel metal strap tags were the principal tags employed. All fish caught by anglers were returned to the Game and Fresh Water Fish Commission for information regarding growth rates of which negative data was obtained. Comparisons were made of the percent returns of each of the three tags represented, plus the Spaghetti tag was compared in two different locations on the fish. The external effects on the recaptured fish showed 258 either slight or heavy infections caused by the initial tag wound or by irritations of mechanical, chemical or biological origin. This study was made in conjunction with the Florida State-wide Fish Tagging Program Sponsored by the Schlitz Brewing Company.

The research function at the Pascagoula Technological Laboratory is described. The staff, the equipment, and the microbiology and chemistry programs are briefly discussed. Biochemical studies of fish and shellfish are a major program at the laboratory. The deterioration of fresh iced shrimp was studied recently by following the increase in pH, analyzing the amino acid, hydroxyproline, and evaluating the variation in the nitrogen values of fractions eluted by different solvents. Microbiological studies accompanied the biochemical studies. Daily total plate counts demonstrated the increase in microorganisms as the shrimp became less acceptable as a food. Fluctuations in the types of organisms present were shown to be related to the changes that took place in the iced environment as the salinity--and the marine bacteria--decreased.

Laboratory experiments were conducted to determine the acute and chronic effects of endrin to estuarine fishes. Short-term bioassays in flowing seawater determined 24-hour LC50's for spot (Leiostomus xanthurus), mullet (Mugil cephalus), menhaden (Brevoortia patronus), longnose killifish (Fundulus similis), and sheepshead minnows (Cyprinodon variegatus). A population of spot was exposed continuously for eight months to a sublethal concentration (0.05 ppb.). No pathology was found in the spot after seven months of exposure, but, a three-week exposure to a near-lethal concentration (approximately 0.075 ppb.) produced pathology characterized by systemic lesions involving the brain and spinal cord, liver, kidneys and stomach. Residue analyses (gas chromatography) of spot exposed to 0.05 ppb. endrin for five months revealed an accumulation of 78 ppb. (micrograms/kilogram). No endrin could be detected in these fish after a 13-day holding period in uncontaminated water.

A description is given of the physical f,acilities in which mass cultures of penaeids have been reared from eggs to postlarvae. The metal chelator EDTA was added to the water in which the shrimp were grown. Larvae of Penaeus aztecus developed more rapidly, at 30° C than at lower temperatures. Salinity varied from 20.5% to 36.0% during rearing trials in which P. aztecus Iarvae were reared to postIarvae. Addition of mixed, algal cultures ,as food g,ave better survival than additions of their individual components. EDTA was used as an additive to filtered sea water to grow a diatom, Skeletonema sp., in mass culture, as food for larval shrimp.

The spotted seatrout, Cynoscion nebulosus, are found throughout the year in the Biloxi Marsh Area in southeastern Louisiana. A total of 368 stomachs were analyzed; 152 were empty. Fish occurred in 74.4 per cent of these stomachs and crustaceans in 25.3 per cent. During the summer months fish and crustaceans were comparable in per cent occurrence as food items. In this same period food availability samples showed that crustaceans had become more prevalent. This suggests a correlation of the food habits of the spotted seatrout to food availability. Fish seem to be the most important food group in the Biloxi Marsh Area utilized by the spotted seatrout.