Summer Feeding Habits of River Otters Inhabiting a Contaminated Coastal Marine Environment

Abstract

Abstract In two recent studies, North American river otters (Lontra canadensis) inhabiting the urbanized/industrialized harbors of southern Vancouver Island, British Columbia, Canada were found to be exposed to elevated levels of environmental contaminants, primarily industry-produced polychlorinated biphenyls (PCBs). Contaminant exposure in those studies was assessed non-invasively, by measuring chemical residue concentrations in river otter feces collected from established marking sites (latrines). As river otter exposure to contaminants is primarily through their diet, our aim was to characterize river otter prey selection from feces collected at latrine sites inside the contaminated harbors and along the relatively uncontaminated coastline outside the harbor systems. Fish occurred in 95.5% of all feces analyzed, with species of gunnels (Pholidae), sculpins (Cottidae), pricklebacks (Stichaeidae), toadfish (Batrachoididae), clingfish (Gobiesocidae), flatfish (Pleuronectiformes), and snailfish (Liparidae...