River otter (Lontra canadensis)

Photo: Jim Leopold/USFWS

Within the inland waters of Washington and British Columbia, river otters forage in marine waters where they depend upon healthy shorelines and healthy intertidal and subtidal areas. In this marine habitat they eat numerous species of fish and invertebrates and play an important role in the near-shore marine ecosystem. Current information regarding river otter abundance and distribution in the inland waters is scarce. The closely related European river otter (Lutra lutra), historically distributed over much of Europe, has experienced a marked reduction in range and has completely disappeared from large areas. Many of the potential reasons suggested to explain the disappearance of river otters in Europe are speculative, but there is convincing evidence that decreases in otter populations are closely tied to increased anthropogenic (human-induced) environmental impact. Anthropogenic factors that may have contributed to loss of the European river otter, such as habitat loss, decreased water quality, and increased pollution, are all present in varying degrees throughout the inland waters, yet a thorough understanding of the health of this population is lacking. The SeaDoc Society has initiated an assessment on the current health status of Washington's Inland Sea river-otter population in order to better understand the threats faced by this population. River otters are on the British Columbia "watch list" to be actively monitored and studied. One-page fact sheet about river otters (pdf format) Gaydos, J. K., P. A. Conrad, K. V. Gilardi, G. M. Blundell and M. Ben-David. 2007. Does human proximity affect antibody prevalence in marine-foraging river otters? Journal of Wildlife Diseases 43: 116-123. (PDF)