Habitats play a crucial role in mulding life histories, yet each organism's habitat, like each organism's life history, is unique. The role of a different habitat usage among populations of striped bass Morone saxatilis in relation to their PCB exposures has been studied in the area of the Hudson River Estuary and Long Island. The habitat usage history of individual fish was assessed by measuring the relative amount of strontium and calcium annual deposits within the otoliths. Since sea-water is richer in strontium than freshwater, bony deposits, deposited when the fish is in marine waters, are more enriched in strontium than those deposited while in freshwater. Otoliths demonstrated that the striped bass population is comprised of individuals with widely varying migration patterns, showing both a 'typical' migration pattern and a residential behavior. This small group, constituted mainly of males, showed a highly significant positive correlation with PCB body burden, while confusing factors such as lipid content, length, age, sex, and weight were poorly correlated to the magnitude of contaminant body burdens. Striped bass, permanently residing in portions of the estuary adjacent to PCB sources, showed elevated total PCB levels with patterns mainly constituted of di-, tri-, and tetrachlorobiphenyls, whereas fish that spend the majority of their life in more saline waters of the estuary or in migrating contain lower PCB levels composed of more highly chlorinated congeners.
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