EFFECTS OF LINDANE ON THE PREDATOR-PREY INTERACTION BETWEEN HYDRA-OLIGACTIS PALLAS AND DAPHNIA-MAGNA STRAUSS

Laboratory tests were developed to allow identification of the effects of toxicants on the predator-prey interaction between Hydra oligactis Pallas and Daphnia magna Strauss. Three test methods, which differed with respect to initial Daphnia population, test period, and managemen t of predation level, were used to determine the influence of the orga nochlorine insecticide lindane on the interaction. The criteria examin ed were the population structures of the two species. The lindane trea tments did not alter the production of Hydra. However, the final popul ation structure of Daphnia was variously affected by the toxicant in t he different test systems. The most sensitive endpoint, with a lowest observed effect concentration of 4 mu g/L lindane determined after a 1 4 day exposure period, was increased recruitment of juvenile Daphnia i n a test system which incorporated management of the Hydra. The result s are compared to previously reported data derived from single species chronic tests, and the suitability of the test methods for hazard eva luation is discussed.