Sea Otter Conservation Workshop VIII
Michael J. Murray also contributed to this piece.
From Friday afternoon March 22 through Sunday March 24 sea otter conservationists, researchers, veterinarians, trainers, program managers, graduate students, field workers, advocates and others folks met at the Seattle Aquarium and discussed all things sea otter. The total group of around 80 people at any one time exchanged information on sea otter populations trends in Alaska, the Kuril Islands of Russia, British Columbia, Washington and California; a wide variety of small and large research projects; management of captive sea otters; health and veterinary care; physiology and breeding. Despite the sequester of Federal funds many employees of Federal agencies were able either to attend or do remote presentations. As always, the Seattle Aquarium was a warm and thoughtful host and made everyone feel welcome.
On the population front the news is generally good. Populations in the Aleutian Islands have stabilized and those in Southeast Alaska are growing, some of them very rapidly. This is causing conflict with several Alaskan fisheries and has resulted in a call for various forms of ‘take’ from increased native harvest to bounties. The population in British Columbia, that was transplanted there about 40 years ago is also doing very well. The Washington population is growing but is currently bunched up around some small islands in the middle of their range making it vulnerable to a catastrophic oil spill. California’s sea otters are stuck in recovery, with current growth rates and with no setbacks it might meet USFWS around 2040.
Several presenters covered various parts of what is called the Pacific Nearshore Project and amazing interconnected set of research projects that covers many aspects of sea otter biology and the connections between land and sea. Shawn Larson presented the genetic analysis of otters sampled as part of the Pacific Nearshore Project and compared the results to work done 15 years ago. Interestingly, overall genetic diversity has increased in all populations (several in Alaska and California as well as BC and Washington), although diversity is generally a bit lower in Prince William Sound and all California populations. It was also notable that some individual California otters had as much genetic diversity as Alaskan otters, while other had less, dropping the mean diversity to a statistically significantly lower level.
A correlation Dr. Larson had previously reported between corticosterone (a measure of adrenal function) and genetic diversity, was not seen in this larger, newer and more comprehensive sampling. A series on formal and informal discussions followed during the meeting as to the potential value and wisdom of proposing to bring Alaskan sea otters to California in hopes of increasing genetic diversity. Jack Ames, sea otter biologist extrodinaire and keynote speaker at the workshop banquet, postulated that some of the male aggression seen in southern sea otters might be modulated in northern sea otters were introduced to California. Others countered that experimental work in rats and statistical association studies in humans provide evidence that male aggression is influenced by sub-lethal Toxoplasma infection, and that could explain why Alaskan male sea otters are generally less commonly reported to injure females during sexually interactions than California males. Feelings run high on both sides of this debate and, clearly, such an experimental mixing isn’t going to happen, or maybe even be formally proposed, any time soon.
It was also interesting to note that large range movements have been noted in some male northern sea otters, and that sea otters transplanted to Washington and British Columbia are almost certainly beginning to mix with one another. Northern sea otters (Enhydra lutris lutris), presumably from the Washington population, have been occasionally found along the Oregon coast, one as far south as Coos Bay, OR (male otters recovered dead). Similar documentation exists for southern sea otters (Enhydra lutris nereis) as far north as Arcata, CA (see The Humboldt County Sea Otter Mystery). So some limited mixing of northern and southern sea otters populations may occur at some time in the next decade or two with little or no help.
Tim Tinker, presenting remotely from California, discussed the serious impact that white shark related mortality is having on southern sea otters.
Some veterinary aspects of sea otter conservation were also presented, including dramatic video of a case of West Nile virus infection and encephalitis in a sea otter by Pittsburgh Zoo and Aquarium staff. This is the first such documented case and the cause was confirmed by microscopic pathology, serology, and polymerase chain reaction for virus specific nucleic acid sequence.
Many of the zoological institutions that hold sea otters were represented and the status of their otters, some of the novel programs for them, and the telling of conservation stories to the public were presented. These institutions reported on progress on coordinating captive sea otter population management in U.S. zoos and aquariums such that sea otters from non-listed populations may be eligible for transfer to qualified zoos and aquariums in Europe.
The Seattle workshop generated discussion about the concept of, needs for, and potential support of a “sea otter fund” which might solicit monies from a variety of sources that could be used to support various sea otter conservation projects. A common theme unifying this workshop was the desire of a wide variety of agencies, organizations and institutions to contribute to sea otter conservation.