Effect of parental exposure to o,p̕ -DDT on the behavior of Atlantic croaker, Micropogonias undulatus, larvae

Three behavioral assays were evaluated as indicators of sublethal toxicity due to parental exposure to o,p'-DDT in Atlantic croaker, Micropogonias undulatus, larvae. Responses to separate visual and vibratory stimuli as well as routine swimming activity were quantified using image and motion analysis equipment. Of the variables examined, proportion of larvae responding to a vibratory stimulus, swimming speed, active duration, and pause duration were the most sensitive indicators of exposure to o,p'-DDT. Average and maximum burst speeds in response to the visual stimulus were higher for control larvae. However, these same measurements were not different among treatments in response to the vibratory stimulus. The proportion of larvae responding to the vibratory stimulus was significantly higher for unexposed (control) larvae only after yolk and oil absorption. Effects of DDT exposure on routine swimming activity were only observed prior to complete oil absorption. During this time, apparent swimming speeds were reduced for exposed larvae due to decreases in the duration of active swimming and increases in the duration of intervening pauses. The implications of these behavioral changes for the survival of parentally exposed larvae are discussed