Robert J. Muncy

Non-radioactive rare earth elements (REE) were evaluated as potential markers in scales of hatchery-reared juvenile striped bass Marone saxatilis over a 12week feeding study. Uptake and retention levels of europium (Eu) and terbium (Tb) detected by neutron activation analyses at below 1 p,g/g could be related directly to dietary concentrations of the 2 elements and duration of feeding. Decreased relative concentrations following post-feeding could be related to scale mass increases and the inherent problem with detection techniques which analyze for amounts per unit mass. We compared our...

Scales of largemouth bass taken from two ponds at Baton Rouge, Louisiana over a three-year period agreed closely with the known past stocking history on these fish. Largemouth bass scales from a 50-acre pond at Clinton, Louisiana indicated agreement with the six years fish had been stocked. Total length growth rates of bass were increased by controlled fall drawdown; however, prolonged summer droughts decreased total length growth and condition factors. Spawning and drastic drawdowns resulted in more pronounced growth checks than winter cessation on the scales of bluegill and redeal'...

Complete fish mortality associated with the development of high populations of dinoflagellates (Gymnodinium spp.) was observed in 1960 in a 9.5 acre fresh-water lake at Baton Rouge, Louisiana. Toxicity of the water samples containing the algae appeared to be related to the increased pH, length of exposure to sunlight and concentration of algal cells. Filtration with activated carbon removed the toxic effects. Laboratory tests offered data to explain the course of the fish mortality in the lake.