Concentrations of Organochlorine Substances in Relation to Fish Size and Trophic Position:  A Study on Perch (Perca fluviatilis L.)

The aim of this study was to evaluate the importance of trophic position as a determinant of the concentrations of organochlorine substances (OCS) in fish. Perch (Perca fluvatilis) was selected since the species increases in trophic level over the course of its lifetime. The trophic position was characterized by stable isotope analysis of nitrogen and gut content. Perch (130 individuals) of different lengths and of both sexes were analyzed for polychlorinated biphenyls and chlorinated pesticides. There were no pronounced differences in the OCS concentrations between the perch sexes. Perch up to a length of 20 cm did not show any increase in OCS concentrations with increased length, despite …