Jack Herring

Fish Population Estimate Methods Evaluated By A Total Drawdown

The fish population of Lake Columbia, a 36.42 ha Mississippi impoundment, was estimated by shoreline seining, mark and recapture, rotenone sampling and gill netting. The impoundment was then drained to evaluate results. Shoreline seining provided an excellent estimate of population balance. Mark and recapture oflargemouth bass (Micropterus salmoides) gave a statistically valid estimate and was the only method to which statistics could be applied. Length-frequency data of bass from rotenone samples were stable and appear useful, although large bass were underestimated. Rotenone samples gave...


Pesticide Residues Of Twenty Mississippi Delta Lakes

In 1969 the pesticide concentrations of 20 randomly selected Delta Lakes were evaluated by gas chromatograph. The DDT complex and toxaphene were the prevalent pesticides found in water, fish and bottom sediment. Lake waters were generally low in pesticide residues. Pesticide residues of DDT+metabolites and toxaphene in fish flesh ranged respectively from 0.15-10.60 p.p.m. and 0.0-20.0 p.p.m. Bottom sediment contained from 0.02-3.58 p.p.m. DDT+metabolites, while toxaphene ranged from 0.0-2.47 p.p.m. All lakes surveyed were found to contain pesticides.