Sea Otter Research

Sea Otter by Mike Baird
Sea Otter by Mike Baird

The SeaDoc Society is improving the health of marine wildlife populations and the ecosystem upon which they depend by funding critical research, providing scientific support, and bringing stakeholders together. Like many SeaDoc Society-funded research projects, a recently completed project on sea otters is providing new information that is being used to better manage living marine resources.

By the early 1900s, Washington’s sea otters had been hunted to extinction. Thanks to translocations of wild sea otters from Alaska in 1969 and 1970, the population now numbers over 550 animals. With this successful repopulation comes a glimpse of what an expanding sea otter population could mean for some of the communities that have become accustomed to living without sea otters. Although Washington’s sea otter population resides on our outer coast, some of the animals occasionally venture into the Strait of Juan de Fuca, forage for a while, and then return to the outer coast. Sea otters have very high metabolisms and can eat a lot of crabs, clams, urchins – up to 25% of their body weight daily. While their appetites bring sea otters into conflict with shellfish fisheries, sea otters also play an important role in increasing kelp forest biodiversity because the otters eat urchins that can otherwise overgraze on kelp forests.

Researchers just completed a SeaDoc Society-funded project that studied whether the presence of sea otters in the Strait of Juan de Fuca enhanced the health and biodiversity of kelp forests in the Strait. They also investigated whether sea otters moving into the Strait would conflict with tribal, commercial, and recreational crab, urchin, and clam fisheries. Dr. Glenn VanBlaricom, a senior scientist with the Washington Cooperative Fish and Wildlife Research Unit at the University of Washington, and his graduate student Melinda Chambers used SCUBA surveys to compare the flora and fauna in 11 sites along the southern shore of the Strait of Juan de Fuca that were occupied by sea otters between 1997 and 2001 to eight sites that were not.

While findings showed that sea otters are impacting urchin, clam, and crab populations, they did not support the hypothesis that foraging by sea otters enhanced local biodiversity. The scientists thought this might be because other factors are as important or more important in shaping kelp forests in the Strait, like strong currents and storms. These data are now being widely shared and discussed with wildlife managers that are responsible for sea otter recovery (WA Department of Fish and Wildlife (WDFW) and the US Fish & Wildlife Service), as well as with those that are responsible for sustainable shellfish harvest in the Strait of Juan de Fuca (WDFW, WA Dept of Natural Resources, the Olympic National Park, the Makah Nation, the Lower Elwha Klallam Tribe, the Jamestown S'Klallam Tribe, and the Clallam County Marine Resources Committee).

If sea otters do indeed permanently occupy the Strait of Juan de Fuca, these groups will need to work together strategically and productively to balance the harvest needs of both people and sea otters. VanBlaricom’s report represents the best data available on the subject and provides a foundation for informed decision-making. A pdf of the report can be downloaded here.

Thank you again for your interest and investment in the SeaDoc Society and in our shared vision that together we can secure a healthy and sustainable marine ecosystem for ourselves and generations to come.


Kirsten V.K. Gilardi, DVM, Dipl. ACZM Program Coordinator

Joseph K. Gaydos, VMD, PhD Staff Scientist

Sea Otter photo by Mike Baird via Flickr. Creative Commons license.