Flounder health status in the Seine Bay. A multibiomarker study

The Seine Bay is used as a pilot area to assess the usefulness of monitorin g programmes using a suite of biological measurements. These biomarkers inc luded ethoxyresorfin-O-deethylase (EROD) and acetylcholinesterase (AChE) ac tivities, multixenobiotic resistance (MXR) protein expression level assessm ent and gonad histopathology. Samples of European flounder collected in thr ee sites close to the Seine Estuary in late September 1998 showed that 8% o f the males were intersex, i.e. had gonads with both male and female tissue s. Another 10% of individuals, identified as male by morphological observat ion during sampling, showed only female tissues on histological sections. T hese dramatic changes were associated with different patterns of EROD activ ity, MXR expression or AChE activity inhibition that might reflect shorter time effects of xenobiotics and constitute a starting point to integrate bi ological responses for the assessment of the health status of flounder in t he Seine Bay. (C) 2000 Elsevier Science Ltd. All rights reserved.