Monthly insecticide tests on waters from two Yazoo-Mississippi Delta Oxbow Lakes show DDT levels to be highest in winter and spring months. Comparison of insecticide levels in Wolf Lake and Mossy Lake waters, muds, and fish flesh show consistantly higher levels in Wolf Lake. Thirty-six hour bluegill bioassays in endrin show TLm value of Wolf Lake fish twenty fold greater than Mossy Lake fish. Two hundred thousand largemouth bass (Micropterus salmoides) fingerlings placed in Wolf Lake May 16-25, 1968 showed no survival upon repeated checks with :14" mesh seine, electrical fish shocker, and two one-acre population studies. Monthly comparisons of pH, D.O., Free CO2 , total hardness, methyl orange alkalinity, nitrate nitrogen, ortho-phosphate, plankton counts, and benthic samples failed to account for the decline in carnivorous fish species in Wolf Lake and the inability to re-establish a largemouth bass population. Modern farm practices and drainage patterns, which make a virtual agricultural sump of many Yazoo-Mississippi Delta Lakes, have made them void of fish at the top of the food chain and prevents re-establish. ment of largemouth bass populations.