The influence of ecological factors in the modulation of pollution biomarkers of two small pelagic marine fish.

Biomarkers are useful tools for the detection of marine pollution, which is poorly monitored in the pelagic environment. In this study, we investigated the role of key biological and environmental factors on three hepatic xenobiotic biomarkers: carboxylesterases (CEs), glutathione S-transferase (GST) and catalase (CAT). Additionally, ethoxyresorufin-O-deethylase (EROD) and benzyloxy-4-[trifluoromethyl]-coumarin-O-debenzyloxylase (BFCOD) activities were determined for comparative purposes. The pelagic species targeted were the European anchovy (Engraulis encrasicolus) and the European sardine (Sardina pilchardus). The results revealed sex-dependent CE activities in sardine. CEs and GST activities were significantly affected by reproduction and, in anchovy, CE activities were also influenced by temperature. In vitro incubations revealed that the pesticide dichlorvos caused up to 90 % inhibition of basal CEs activity. This work highlights that the reproductive status, temperature and sex, modulate biomarker responses, and that anchovy would be more suitable pelagic bioindicator due to its higher in vitro sensitivity to dichlorvos and sex-independent biomarker responses.