Fish larvae assemblage of a coastal area under influence of petrochemical activities, in Todos os Santos Bay, Bahia, Brazil

Abstract

Todos os Santos Bay, having an area of approximately 927 km ² , is the largest Bay on the Brazilian coast. Four sampling surveys, in two rainy and two dry periods, were made at five locations of Todos os Santos Bay, Bahia, Brazil, aiming to identify environmental and ecotoxicological correlates of ichthyoplankton assemblage structure. The study area showed a community characterised by the domination of Engraulididae, Gobiidae (Gobionellus spp.), Gerreidae (Diapterus spp. and Eucinostomus spp.) and Carangidae (Oligoplites spp. and Caranx spp.) larvae. There wasn't a significant difference in composition of fish larvae between the sampling periods, but there was a significant temporal variability in the most important environmental variables. The results showed statistically significant differences between northern stations and the control site, only for ammonium–nitrogen and total fish larvae density. The environmental variables (temperature, ammonium-nitrogen, oil and grease and chlorophyll a) explained 94.7% of the variation of the larval fish assemblage.

Keywords:

• ichthyoplankton
• environmental assessment
• refinery
• effluents
• marine pollution

Acknowledgements

This study was made possible through the Program for Monitoring of the Ecosystem of North of Todos os Santos Bay, which was established in 1994/1995 by the Instituto de Biologia of Universidade Federal da Bahia and PETROBRAS (Petróleo Brasileiro Co.). The comments on the manuscript made by the anonymous referees were greatly appreciated.