A recent report claims that reintroducing sea otters to the Oregon Coast is feasible and beneficial to the state’s marine ecosystem if certain best reintroduction policies are followed. However, sea otters’ voracious appetites for certain invertebrates may have “consequential” impacts on fisheries in the region.
Sea otters have an outsized impact on the ecosystems they inhabit, making them a “keystone species” with little or no other species likely to replace them. The report explains how sea otters’ role in a marine food web naturally limits sea urchins and other large invertebrate species, such as Dungeness crabs.
“Nibbling on sea urchins, [a sea otter] helps kelp forests thrive, and by crunching on crabs, it promotes eelgrass in estuaries,” according to a Monterey Bay Aquarium fact sheet. All that uneaten kelp helps “draw up [carbon dioxide] of the overlying atmosphere, thereby potentially influencing carbon sequestration,” the report notes.
But while the report noted that the return of sea otters to the Oregon coastline would be celebrated by local Indigenous peoples with deep spiritual ties to the marine mammal, not all locals would necessarily encourage the recovery effort.
With sea otters extirpated from the Oregon coastline for more than a century, commercial and recreational fishing has had no non-human competition for invertebrates that are harvested and sold for human consumption, the report explains. Although the researchers said it was difficult to predict the extent of negative impacts on some invertebrate species, Dungeness crabs, Red crabs, Razor clams, Butter clams, Gaper clams, Clams, Cockles , mussels, ghost shrimp and red and purple seas. sea urchins would all be “potentially…affected by sea otter recovery.”
“Some of these fisheries are worth hundreds of thousands of dollars per year, even… tens of millions of dollars, so the potential economic impacts of even a small reduction due to sea otter recovery are substantial,” the report notes. . “However, while for some fisheries…there is good reason to predict a substantial negative impact from the recovery of sea otters, in the case of others…it is far from clear whether there would be an impact negative, or how substantial such an effect would be. to be.”
Still, while relocating sea otters to Oregon waters to reestablish the local population is feasible, the report stressed that catches should not exceed about 10 percent of the individual animals that make up a specific group of otters. Models used by the report’s authors showed that removing more than this number could have “population-level consequences”, while capturing less than 10% of a local population “can be sustainable”.
Capture of sea otters in parts of Southeast Alaska “would have little measurable population-level effect” and would be “the best potential source of northern sea otters,” the report notes. However, to “maximize genetic diversity”, sea otters from populations north and south of the Oregon coast should be considered for relocation.
According to the report, sea otters could once be found between northern Japan and Russia’s Kamchatka peninsula, along the Aleutian Islands, along the entire west coast of the United States, and even south into Mexico’s peninsula of Baja California. But an insatiable desire to hunt sea otters for their thick fur coats, later sold in international fur markets, eventually eradicated the creatures from significant parts of their former territory, including Oregon.
Previous attempts to relocate and reintroduce sea otters to areas of their historic range have shown that those involved in the process lack a basic understanding of the creatures’ bodily functions and survival needs. Many sea otters died during the earliest relocation attempts, which the report attributes in part to a lack of clean water, sufficient space and proper food during transport and detention.
Further efforts will show the importance of ensuring that transplanted sea otter populations would also have plenty of prey in their new habitat to consume. Successful relocations of sea otters in the 1960s and 1970s to Southeast Alaska resulted in population growth that eventually led to current estimates of over 25,000 individual otters in that region.
An Oregon-based nonprofit known as the Elakha Alliance — made up of tribal, academic and conservation actors focused on sea otters and marine ecosystem conservation — released the report in January.
The authors of the 12-chapter report included current and retired staff from the US Geological Survey, the Seattle Aquarium, the Monterey Bay Aquarium and the University of Oregon.