General condition biomarkers in relation to contaminant burden in European flounder (Platichthys flesus).
In respect to the differences found for vitellogenin (VTG) expression in male and immature flounder, general biological aspects and a set of chemical residues in the liver were compared between flounder from the Mersey and Dee estuaries (UK). Except for alpha-HCH, all pollutant chemicals analysed in flounder liver differed highly significantly between Mersey and Dee fish. Overall, the higher liver contaminant concentrations were found in VTG-induced Mersey flounder. The biomarkers studied were not found to indicate significant differences between Mersey and Dee fish. However, when all of the minor differences are taken into consideration, it appears that the slightly lower growth rates after age 2 in Mersey flounder, lower gonadosomatic index in both mature male and female animals, less precise seasonal patterns of condition factor (CF), hepatosomatic index and gonadosomatic index, and lower CF in immature Mersey fish may well be signs of a contaminant-affected Mersey population.