Reduction by a surfactant of olfactory mediated attraction between juveniles of arctic charr, Salvelinus alpinus (L.)

Abstract

The effect of sublethal concentrations of linear alkylbenzene sulphonate (LAS) on attraction to conspecific compounds was studied in juvenile Arctic charr, Salvelinus alpinus. In a fluviarium single fish were observed over nine consecutive 90-min test periods in darkness choosing between two flows, the one containing charr odour, the other not. After each 90-min period the flows were exchanged. Sixty-three subjects were tested. Four different types of test were run: control test; attraction test; attraction test after 96 h pre-exposure of test fish to 1–2 ppm LAS; attraction test with LAS distributed to all parts of the test area during four of the test periods. Intact charr always showed strong and steady attraction to water conditioned by conspecifics. Pre-exposure to 1–2 ppm LAS significantly reduced chemo-attraction. Simultaneous supply of 0.02 or 0.2 ppm LAS to the test area significantly decreased attraction, while 1.0 ppm LAS completely quenched the attraction. Chemo-attraction was still significantly reduced during the test period immediately after the supply of 0.02 or 1.0 ppm LAS was stopped. Locomotor activity was affected only during supply of 1.0 ppm LAS into the test area. The chemo-attraction studied in Arctic charr may possibly be used in behavioural-toxicity testing of xenobiotics in sublethal concentrations.