Effects of cadmium on the behaviour of Cnesterodon decemmaculatus

Abstract

Recognising biomarkers for assessing early ecotoxicity effects using test species exposed to reference toxicants is important, hence the aim of this work was to study changes in some behavioural parameters of Cnesterodon decemmaculatus. Fish were under stress conditions induced by exposure to a subtoxic concentration of cadmium (Cd) in the laboratory. Acute bioassays (96 h) were performed under laboratory conditions, with medium renewal every 48 h. Animals were randomly assigned into two groups of 10 individuals each: Cd-exposed (0.50 mg Cd. L -1 ) and control (moderate tap water). Both groups were video-recorded every day for 15 min at the same time of day. Each individual was evaluated for: a) aggressive behaviour; b) sexual behaviour; and c) swimming alterations. Fish exposed showed irregular swimming, hyperactivity periods, fewer copulation attempts and same aggressive behaviour as compared with the control group. Our results suggest that these behavioural alterations may serve as early and reliable biomarkers.

Evaluation of the Acute Effects of Arsenic on Adults of the Neotropical Native Fish Cnesterodon decemmaculatus Using a Set of Biomarkers

“…It is worthy to mention the importance of analyzing data by sex for a more precise evaluation of behavioral parameters, which otherwise may be affected by significant data dispersion. Sexual behavior differences have been reported for C. decemmaculatus exposed to cadmium in ecotoxicological studies (Ferro, 2017, 2019) and we observed that As altered the acceleration and maximum velocity in females. The present study showing a differential effect of As on the swimming behavior of males and females provides a preliminary baseline to be used in future behavioral studies and in environmental monitoring.…”