Cadmium-induced disruption of environmental exploration and chemical communication in matrinxa, Brycon amazonicus

The effects of cadmium exposure on both environment exploration and behavioral responses induced by alarm substance in matrinxa (Brycon amazonicus), a fish species endemic to the Amazon basin, were investigated. Fish exposed to 9.04 +/- 0.07 mu g/L waterborne cadmium for 96 h followed by 24 h depuration period in clean water, were video-recorded for 15 min, followed by immediate introduction of conspecific skin extract to the tank and a new 30 min period of fish video-recording. Cd-exposed matrinxa showed a significantly lowered locomotor activity (t-test t(12) = 2.7: p = 0.025) and spatial distribution (t-test t(12) = 2.4; p = 0.03) relative to the Unexposed control fish prior to the alarm Substance introduction. and did not present any significant reaction when the skin extract was introduced. The control fish, in opposite, showed a higher level of activity and spatial distribution prior the skin extract contact and significantly decreased their response after the chemical stimulus (locomotion-repeated-measure ANOVA F-1,F-11 = 5.6; p = 0.04; spatial distribution F-1,F-11 = 19.4; p = 0.001). In Conclusion, exposure to a low level of cadmium affects both the environment exploration performance and the conspecific chemical communication in matrinxa. If the reduced environmental exploration performance of Cd-exposed fish is ail adjustment to the compromised chemical communication or in independent effect of cadmium is the next step to be investigated. (c) 2008 Elsevier B.V. All rights reserved.