Laboratoire d'Ecologie Aquatique INRA, 65 Rue de St Brieuc, 35042 Rennes Cedex, France.
Actometric and olfactometric observations were performed in goldfish to determine the effect of a short-term exposure (8 h) to sublethal concentrations (25, 50, 100 µg/l) of carbofuran, prochloraz and nicosulfuron on behavioral activity and chemobehavioral sensitivity to a combination of amino acids (Ala, Val, Gly, Tau), tested at the same relative concentrations as previously detected in urine of conspecifics. Effect was assessed on seven behavioral endpoints, related to swimming activity and social relations.Exposure to carbofuran significantly increased grouping tendency (50, 100 µg/l), burst swimming reactions (25, 50, 100 µg/l) and agonistic interactions (50 µg/l). Exposure to prochloraz induced a significant increase in the number of buccal movements (100 µg/l). The behavioral activities of nicosulfuron-exposed fish did not differ significantly from those of unexposed fish. Olfactometric stimulation with the combination of amino acids (AA) significantly changed the behavior of unexposed fish (control), inducing attraction and increasing swimming movements, burst swimming reactions, buccal movements and agonistic interactions. The behavioral responses to AA were significantly modified after 8-h exposure to carbofuran, producing a decrease in attraction (50 µg/l), swimming movements (100 µg/l), burst swimming reactions (100 µg/l), buccal movements (100 µg/l), agonistic interactions (100 µg/l) and an increase in sheltering (100 µg/l). Some behavioral responses to AA were also changed in prochloraz-exposed fish, with a decrease in agonistic interactions (25 µg/l ) and swimming movements (100 µg/l) and an increase in sheltering (100 µg/l). Compared to unexposed fish, swimming movements of nicosulfuron-exposed fish (25, 50 µg/l) were significantly decreased during AA stimulation. The chemobehavioral endpoints selected here appear as sensitive and early indicators of toxicity which might be worthwhile to consider in environmental risk assessment.