Sea otters, which nearly went extinct a century ago because of their furry fur on the Pacific coast, may be making their way back to the waters of Northern California.
A feasibility study released this week by the US Fish and Wildlife Service suggests the species could be reintroduced to its historic habitat ranging from San Francisco Bay to Oregon.
The report, presented to Congress earlier this month, makes no recommendation on whether the species should be reintroduced. But it concludes that reintroduction is certainly possible and points to the value of sea otters to the overall ocean ecosystem. Sea otters feed on mussels, crabs and clams, so the obvious downside would be an added strain on the shellfish population and the commercial fisheries that depend on them.
The cost of reintroduction was estimated to be between $26 million and $43 million over a 13-year period. The 172 page report was requested by Congress as part of the Consolidated Appropriations Act 2021.
“Sea otters play a critical role in our near-coastal marine ecosystems,” said Michele Zwartjes, co-author of the report and supervisor of the Oregon Coast Field Office for the US Fish and Wildlife Service. “They are a keystone type. They maintain the balance in that system as predators of sea urchins in particular.”
Without sea otters, sea urchin populations have exploded and devastated kelp forests, Zwartjes said. Kelp is highly efficient at capturing carbon, a key element for global warming — so if the otters did eventually return, it would help revitalize underwater kelp forests and seagrass beds. The kelp and seagrass form a breeding and foraging area for fish and seabirds.
Economically speaking, the otters are also a huge tourist attraction, due to their preference to float on their backs while using tools to break open their prey, a photogenic process.
“All this underlines the crucial role that sea otters play in restoring ecosystems,” says Zwartjes.
Sea otters have traditionally lived along the coast and as far as Japan in the Pacific Ocean. The California coastline had the southern sea otter, a subspecies that is endangered. Less than 50 individual otters are believed to have survived the maritime fur trade, and every sea otter in the state is derived from that population. They are usually from Half Moon Bay to Point Conception, in a narrow range.
“They tend to stay in the same area for most of their lives,” Zwartjes says. “They only have one puppy a year and the population growth, once established, is slow.”
The proliferation of white sharks has contributed to this.
The population of northern sea otters has recovered north from Central Washington, but there is no population to speak of on a 900-mile coastline from that area’s terminus in Washington to Half Moon Bay. The otters commonly seen on the shores and in bays are river otters, although they are often mistaken for sea otters.
Should Congress decide to follow through on the feasibility study and request the U.S. Fish and Wildlife Service to introduce the endangered southern sea otter to California, the pups raised at the Monterey Bay Aquarium could be deposited in San Francisco Bay or other estuaries where they are protected from sharks and extreme weather.
“Eventually, those animals would reconnect with animals in the north, which would increase their ability to adapt to climate change,” Zwartjes said. “We hope that when those animals recover and start feeding on hedgehogs, it will help the kelp population recover.”
Before this could happen, there would be extensive contact with coastal communities and stakeholders. There would be opportunities for public input and targeted socio-economic studies would be conducted. It would be a long and slow process.
“We strive for open and public collaboration around this concept,” says Zwartjes. “Sea otters are an essential native component to restoring balance in the marine ecosystem.”
Sam Whiting is a San Francisco Chronicle writer. Email: switing@sfchronicle.com