Aquaculture and Fisheries Commons^™

Conservation Limnogeology And Benthic Habitat Mapping In Central Lake Tanganyika (Tanzania), Joseph S. Lucas

Theses and Dissertations--Earth and Environmental Sciences

Small scale protected zones are valuable for helping the health and productivity of fisheries at Lake Tanganyika (East Africa). Spatial placement of protected areas relies on accurate maps of benthic habitats, consisting of detailed bathymetry data and information on lake-floor substrates. This information is unknown for most of Lake Tanganyika. Fish diversity is known to correlate with rocky substrates in ≤ 30 m water depth, which provide spawning grounds for littoral and pelagic species. These benthic habitats form important targets for protected areas, if they can be precisely located.

At the NMVA, echosounding defined the position of the 30-m isobath …

Toxicological Studies On Aquatic Contaminants Originating From Coal Production And Utilization: The Induction Of Tolerance To Silver In Laboratory Populations Of Fish And The Chronic Toxicity Of Nickel To Fish Early Life Stages, Wesley J. Birge, Jeffrey A. Black, James F. Hobson, Albert G. Westerman

KWRRI Research Reports

Aquatic toxicity studies were performed on two important coal-derived contaminants, silver and nickel. Silver was investigated with regard to metal-induced tolerance in laboratory populations of the fathead minnow (Pimephales promelas). Fish were exposed to acute silver concentrations following acclimation to sublethal exposures of this metal. Based on median lethal times (LT50), animals which had received 14 days prior exposure to 1.5 and 15 μg Ag/L were three to four times more resistant to silver than were previously unexposed organisms. This metal-induced resistance was not a sustained response. After organisms which had been acclimated to 15 μg/L had been transferred to …

The Induction Of Tolerance To Heavy Metals In Natural And Laboratory Populations Of Fish, Wesley J. Birge, William H. Benson, Jeffrey A. Black

KWRRI Research Reports

Aquatic toxicity studies were performed on two natural populations of fathead minnows. One group of organisms was taken from a metal-contaminated flyash pond associated with a coal-fired power plant and the other group was collected from relatively uncontaminated hatchery ponds. Acute tests indicated that flyash pond fish were significantly more tolerant to cadmium and copper than were hatchery fish. At an exposure concentration of 6.0 mg Cd/L in moderately hard water, the median period of survival for flyash pond fish was 50.0 hr compared to 6.8 hr for hatchery fish. Both groups of organisms were about equally sensitive to zinc. …

Some Variations In Distribution Of Fishes In Large Mainstream Reservoirs Associated With Artificial Cover, Donald W. Johnson, Elizabeth M. Choinski

KWRRI Research Reports

The influence of artificial cover (brush piles) on fish populations in Kentucky Lake and Lake Barkley was studied. Mature and larval fishes were collected from deep and shallow sites with and without cover in a bay of each lake. Highest densities of mature crappie, bass, and sauger were found adjacent to deep attractors, while larval crappie and minnows were most concentrated at shallow brush piles. Shad (both adult and larvae) were not congregated at attractor sites. Information gathered supports the continuation of artificial cover installation and water level management procedures which will provide high and stable levels through spring spawning …

The Aquatic Toxicity Of Organic Compounds To Embryo-Larval Stages Of Fish And Amphibians, Jeffrey A. Black, Wesley J. Birge, Willaim E. Mcdonnell, Albert G. Westerman, Barbara A. Ramey, Donald M. Bruser

KWRRI Research Reports

Aquatic toxicity tests were conducted on 11 organic compounds considered hazardous to water resources. The toxicity of each compound was evaluated using embryo-larval stages of two to eight fish and amphibian species. Exposure was initiated at fertilization and maintained through 4 days posthatching. The animal test species exhibited varying degrees of sensitivity to the selected toxicants. Combined frequencies for mortality and teratogenesis at 4 days posthatching gave LC₅₀ ranges of 3.66 to 8.25 mg/L for benzene, 1.16 to 22.42 mg/L for carbon tetrachloride, 0.11 to 1.20 mg/L for chlorobenzene, 2.03 to > 68 mg/L for chloroform, 3.01 to 5.56 mg/L …