|River otters - photo by Dmitry Azovtsev [CC-BY-SA-3.0]|
First off - for anyone who doesn't already know - sea otters and North American river otters are two different critters. They belong to the same Family (Mustelidae) and Subfamily (Lutrinae), but their Genus and, of course, Species are different. The North American river otter's genus and species is Lontra canadensis, while the sea otter's is Enhydra lutris.
According to Wikipedia, the habitats of river otters and sea otters can overlap, because river otters can live along coastal shorelines and estuaries, as well as inland rivers. But sea otters are much bigger animals, tipping the scales at 30-100 pounds, as opposed to the river otters' 11-31 pounds adult weight.
Just like their classifications, the stories of these two animals' history in Oregon have similar beginnings, but not necessarily the same ending.
Let's look at the river otter first.
I guess I always had some vague idea that you wouldn't have to go too far out of the metro area to find a stream that could support a river otter population, but I just never thought that they were alive and well as close to downtown Portland as Oaks Bottom, or Smith and Bybee Lakes. Although the Willamette River has its share of pollution problems, they're apparently not at a level that would prevent river otters (which are very susceptible to environmental pollution) from existing, if not thriving in the area. Kudos to the various municipalities and organizations working to clean up the river since it hit its environmental low point sometime in the early-to-mid 1900s. A study by the USGS, which used otters as a "sentinel species" to judge the health of the Lower Columbia River found PCB levels in otters greatly reduced between 1979 and 1994. That same study, in 1994, "found a relatively dense river otter population throughout the study area, including the heavily polluted portion of the (Columbia) River within the Portland-Vancouver area."
Like most fur-bearing mammals in North America, the river otter populations greatly declined as a result of the fur trade. Habitat loss and pollution has reduced their numbers even further. But as long as we continue to clean up our rivers, and protect vital natural areas along the Willamette and Columbia Rivers in the metro area, river otters should have a bright future here.
No so for sea otters in Oregon. The future remains to be seen (funny thing about the future), but there are currently no Oregon sea otter populations outside the Oregon Zoo and the Oregon Coast Aquarium. This is a direct result of the fur trade. The thick fur (the thickest of any mammal) that keeps sea otters insulated in the frigid Pacific Ocean, became a major target for the fur trade - expanding from Russia in the early 18th century, through the Aleutian Islands, and south along the west coast of North America in the late 18th and early 19th centuries. By 1911, perhaps only 1,000–2,000 individuals remained in the wild. Fearing extinction (finally), the United States, along with Russia, Japan, and Great Britain (for Canada) signed the Treaty for the Preservation and Protection of Fur Seals, which included a moratorium on the sea otter harvest.
|Sea otter - photo provided by Otter 501 and Sea Studios Foundation|
Sea otters were thought to be extinct in California until a population of about 50 was discovered near Big Sur in 1938. All sea otters in California today are descendants of those 50 individuals.
In Washington, 59 sea otters were relocated from Alaska in 1969 and 1970. Surveys in the early 2000s recorded between 504 and 743 individuals.
There have been attempts to re-establish populations in Oregon, as well, but the efforts have not been successful. The Elakha Alliance is working to understand why these attempts have failed, and how they might succeed in the future. Established in 2000, the Elakha Alliance (elakha is the Chinook word for sea otter) is a group of tribes, universities, and other organizations working toward the goal of restoring sea otters to Oregon's coast. The problem is complex, partly because the sea otter is such an important keystone species - a species that has a large effect on the structure and health of its ecological community.
Sea otters depend on healthy kelp forests for their food. These kelp forests provide shelter for fish, sea urchins, and other otter delicacies, and also help keep coastal erosion in check. But when you remove sea otters from the equation, the system begins to break down. With no otter predation, sea urchins (which feed on the kelp) overrun the forests, eventually turning them into "sea-urchin barrens". These barrens can no longer support the rich diversity of species which depended on the kelp forests for survival. So it's kind of a catch 22. For sea otters to survive, you need healthy kelp forests. For kelp forests to flourish, you need sea otters to control the sea urchin population. Hopefully the Elakha Alliance can figure out a way restore the needed balance.
The final element of my otter nexus was the chance to see an advance screening of Otter 501 - a movie about sea otters in Monterey Bay. The movie opens as Katie, a young freshwater biologist from Wisconsin, is settling in to her uncle's vacant apartment on Monterey Bay. She posts a video to Facebook, telling her friends back home about her plans for a six month break in California. Her beach bum intentions go out the window when she finds an abandoned baby sea otter on the beach and reports it to the Monterey Bay Aquarium, which sends staff to rescue the otter. Katie ends up volunteering at the aquarium so she can keep tabs on the otter pup - Otter 501 - but she also learns a lot about sea otters in general, how to observe them in the wild, and how to collect behavioral data. Katie is the primary role in the movie. Aquarium staff and other people have very minor speaking roles. Katie narrates the story through her Facebook posts, which become very popular as she relates the tale of Otter 501's rehabilitation. The narration seems a bit stiff or scripted at times, but the movie includes beautiful footage of the California coast and lots of insight into the aquarium's work monitoring and protecting sea otters in Monterey Bay. I would recommend it to anyone interested in learning more about these iconic animals. Warning to parents - this movie will have your kids asking for a cuddly baby sea otter of their very own! Otter 501 opened June 1st at the Regal Fox Tower.
|Sea otter pups - photo provided by Otter 501 and Sea Studios Foundation|
Other links of interest:
River otters at Oaks Bottom
Photo of a river otter at Smith and Bybee Lakes
Oregon's missing sea otters
2009 Oregon sea otter sighting