Responses of the European flounder Platichthys flesus to the chemical stress in estuaries: load of contaminants, gene expression, cellular impact and growth rate.

European flounder responses to the chemical stress were assessed by a comparative approach on four estuaries displaying contrasted patterns of contamination. The contamination typology of the estuaries was investigated by individual measurements of contaminants in fish. Molecular and physiological responses were studied by gene expression, genotoxicity, neurotoxicity and growth rate. Fishes in contaminated estuaries were characterized by high levels of bioaccumulated contaminants, slow energetic metabolism and reduced growth rate, in contrast to the fish responses in the reference site. A seasonal effect was highlighted for contaminated flounder populations, with high PCB levels, high genotoxicity and elevated detoxification rate in summer compared with winter.