About 100 years ago, biologists estimated there were only about 50 surviving sea otters off the coast of California because their fur was so popular with hunters and trappers. Now that it’s been illegal to hunt them for several decades, that number has improved to about 3,000. That’s still not a lot, so marine biologists have long sought sanctuary areas where sea otter populations could increase.
Their latest proposed sanctuary does not initially make sense. According to Scientific American, marine biologists think the San Francisco Bay should have more sea otters shipped in to ensure the little back-swimmers' safety.
That article cites a new scientific study from the SF State Estuary & Ocean Science Center. Despite the seemingly counterintuitive notion of putting the otters in a heavily commercially trafficked marine shipping corridor, the authors argue that the furry critters will find more shallow areas where ships can’t go in the SF Bay, particularly in Marin County coastal areas.
“The return of sea otters to [San Francisco Bay] could bring benefits to local ecosystem restoration and tourism, in addition to spurring sea otter population growth to meet recovery goals,” the authors state. They conclude that the San Francisco Bay “could provide both suitable habitat and relatively low overall risk.”
The otters may be adorable, but they are very hungry predators. Scientific American notes that they “consume the equivalent of about one-quarter of their body weight every day,” most of their chow being hard-shelled invertebrates that they crack open, like clams, crabs, and mussels. Their introduction to the area has Dungeness crab fishers worried that the otters will gobble up that lucrative crab, though a separate study in the scientific journal Biological Conservation found “no evidence that sea otter populations impact the Dungeness crab fishery in California.”