Effect of Sublethal DDT on the Lateral Line of Brook Trout, Salvelinus fontinalis

The lateral line nerve of brook trout responds to an abrupt low-frequency pressure wave, generated by a falling drop of water hitting the water surface, by a relatively short high-frequency burst of large spikes. The burst duration has a negative temperature coefficient. Exposure of trout for 24 hr to DDT, ranging from 0.1 to 0.3 ppm, renders the lateral line nerve hypersensitive to the experimental stimulus; in particular there is a marked increase, especially at the colder temperatures, in the negativity of the temperature coefficient of the burst durations. The results are discussed in general terms, as well as specifically in relation to other laboratory work which shows that sublethal DDT affects behavioural responses of fish to temperature.