ORGANOCHLORINE CONCENTRATIONS IN LAURENTIAN GREAT-LAKES SALMONINES - IMPLICATIONS FOR FISHERIES MANAGEMENT

To assess species-specific differences in organochlorine (OC) concentrations and sport harvest of Lake Michigan salmonines, and how this may affect human exposure to OC compounds, creel survey and OC analysis data for salmon and trout collected from the western waters of Lake Michigan in 1985 and 1990 were examined. In all species, total concentrations of polychlorinated biphenyls (PCBs) attained the highest concentration of the OC compounds quantified in both study years. DDT and metabolites attained the second highest concentration of OC compounds, in those species in which these compounds were quantified, followed by chlordane and its constituents and dieldrin, respectively. The relative concentrations of PCBs and OC pesticides remained constant between study years in all species, except for brook trout as limited 1990 data prevented analysis. For the mean lengths of each species of salmonines taken by anglers in 1985, lake trout showed the highest concentrations of OC compounds followed by brown trout, chinook salmon, brook trout, rainbow trout, and coho salmon, respectively. In 1990 lake trout again had the highest concentration of OCs followed by chinook salmon, brown trout, rainbow trout, and coho salmon. Brook trout were not in the analysis. Chinook salmon contributed the greatest proportion of OCs to the 1985 sport catch because of its dominance in total biomass of fish harvested. Lake trout contributed the greatest proportion of OCs to the 1990 sport catch, although the second highest in biomass harvested, because of the higher concentration of OC compounds in this species. The concentrations of PCBs declined between study years in all species except brook trout becaused limited 1990 data prevented this comparison. Study results indicate salmonine stocking policies can significantly influence the exposure of sport fish consumers in the Great Lakes region to OC compounds.