Regional Patterns of Persistent Organic Pollutants in Five Pacific Salmon Species (Oncorhynchus spp) and Their Contributions to Contaminant Levels in Northern and Southern Resident Killer Whales (Orcinus orca).

摘要

Previous studies on killer whales (Orcinus orca) have shown that southern residents contain higher concentrations of persistent organic pollutants (POPs) than northern residents and other North Pacific resident killer whale populations. Elevated contaminant exposure in southern residents may be attributed to dietary differences between the two whale populations or to regional differences in concentrations of POPs in their prey. Based on observational data and stomach contents analyses, identified Pacific salmon (Oncorhynchus spp), especially Chinook salmon (O. tshawytscha), as the primary prey of southern and northern resident killer whales in their summer feeding ranges. The main objective of this study was to determine if Pacific salmon had species-specific regional body burdens of contaminants that could differentially affect contaminant levels is northern and southern residents. An additional objective was to measure proximate composition (amount of protein, lipid and carbohydrate) and estimate caloric content of Pacific salmon as an indicator of species- and regionally-specific variation in nutritional quality of prey to killer whales.