.(Un)welcoming Waters: Sea otters poised for comeback to Marin and Sonoma counties

Flippers down, sea otters win the blue ribbon in the cutest critters contest. And to think, in the 18th and 19th centuries, man hunted sea otters to near extinction for their luxurious fur, which contains more hairs per square inch than any other mammal.

The sea otter slaughter lasted about 150 years. By 1911, when the animals became protected under an international fur treaty, less than 2,000 remained, down from an estimated population of 150,000 to 300,000.

Although the sea otter, Enhydra lutris, holds a place on many endangered lists in the United States and other countries, the population never recovered in a significant portion of their historical range, which once ran from the northern islands of Japan to Baja California, Mexico. The largest gap is from the San Francisco Bay to Oregon, where no sea otters remain.

However, the sea otter population in Northern California and Oregon could be on the brink of a comeback. The U.S. Fish and Wildlife Service recently completed a feasibility study on reintroducing the sea otter into these areas. Indeed, not only did the agency conclude it is feasible, but they also determined there would be significant benefits to reestablishing the animals, including improving the genetic diversity of the species and helping to maintain the ecosystem of their habitats.

Overall, the species possesses very low genetic diversity, with the southern sea otter, Enhydra lutris nereis, having the lowest of the three subspecies. By the early 1900s, it was generally believed that the southern sea otter was extinct. However, in 1911, the California Department of Fish and Game discovered 30 to 50 living off the coast of Big Sur. 

Two years later, California made it a misdemeanor to kill or possess a sea otter.

“What the state did was extremely important to preserve that population,” said Lilian Carswell, the southern sea otter recovery and marine conservation coordinator for the U.S. Fish and Wildlife Service.

The conservation laws are working. In fact, the current population of 3,000 southern sea otters descended from the Big Sur stock. Slowly, they’ve expanded their range, occasionally with the help of relocation projects conducted by the U.S. Fish and Wildlife Services. Southern sea otters presently inhabit the coastline from San Mateo County to Santa Barbara County and near San Nicolas Island, about 60 miles from the coast of Ventura County.

Now, if only sharks could read.

“One of the main problems for southern sea otters in California is the high level of shark bite mortality that they’re suffering,” said Carswell. “It’s always been quite high at the northern end of their range, which is San Mateo County, and it’s really ramped up in the southern portion of the Central California range, as well. This has prevented southern sea otters from having any net range expansion in about 20 years.”

Bringing the southern sea otter closer to the range of northern sea otters, found off the coasts of Washington and Alaska, could greatly benefit both subspecies. Interbreeding would certainly increase the genetic diversity in the southern sea otter. With climate change bringing warmer weather northward, the northern sea otter could also gain an advantage from interbreeding, perhaps enabling them to better adapt to new environmental conditions.

Another important consideration in reintroducing the sea otter is its critical role as a keystone species. Sea otters, known as voracious eaters, maintain their ecosystem by controlling the population of their prey. For example, sea otters eat sea urchins. Left unchecked, sea urchins can decimate kelp forests, which provide food and shelter for a large variety of plants and animals.

And kelp forests are currently being depleted by an out-of-control purple sea urchin population. The sea star, another main predator of the purple sea urchin, suffered a devastating population decrease from disease. Sending sea otters back to their historic habitats could help restore the kelp forests.

Slam dunk. Who would oppose the reintroduction of adorable creatures that keep their ecosystems healthy?

For starters, objections may come from the commercial fishermen who will compete with sea otters for crabs, clams, abalone and mussels. It may not be much of a competition either. While sea otters are the smallest marine mammals, measuring about four feet in length and weighing from 50 to 100 pounds, they have high caloric requirements.

On a daily basis, sea otters consume 25% of their body weight in food. Hence, there are very real concerns by the fishermen who make their living hauling in Dungeness crabs and the other invertebrates that sea otters devour. Reestablishing sea otters could disrupt an entire industry right here in Marin and Sonoma counties and beyond.

Dick Ogg, a Sonoma County resident for 62 years, has been fishing most of his life. For the last 25 years, he’s been a commercial fisherman, with his income relying heavily on crabbing. The soft-spoken Ogg is a philosophical enigma. While he believes the ocean resources belong to all, and he’s happy to bring seafood to many a dinner table, as a vegetarian, he won’t partake.

But Ogg is an important voice, representing the fishing community on more than a dozen state and federal committees. He’s worried—extremely so—about the possibility of reintroducing sea otters to the area. The Dungeness crab fishing season has already been substantially shortened due to migrating humpback whales becoming entangled in the fishing gear.

“When you think about what has happened to our industry in the last five or six years, we’re already down to the point where we basically cannot make a living,” Ogg said. “They’re cute, the sea otters, but they are going to eat whatever they can get their hands on. Everybody knows bringing them back is going to affect the crab industry.”

The U.S. Fish and Wildlife Service is quick to say that there is no plan at the present time to reintroduce sea otters to Northern California and Oregon. The agency is still assessing.

“We’re gathering feedback from people up and down the coast right now,” Carswell said. “We’re trying to understand some of the nuances, like exactly where people are fishing, what depths they’re fishing at and what they’re fishing for. No particular sites have been identified yet, so I can’t actually speak to what the effects would be. I will say that past experience has shown us that reintroductions always start small and grow slowly over time. If a sea otter population became established, it would probably take decades.”

Ogg isn’t convinced that sea otter reintroduction should even be considered. It’s his belief that the intervention of man never works out for the betterment of the environment.

“I know the perspective is that the sea otters were here and man wiped them out,” Ogg said. “And that’s absolutely true. But I also understand that it happened 150 years ago, and the crucial environment is nothing like it was back then. It’s very important that we’re sure we’re not making a mistake, because once we’ve done this, there’s no turning back if things begin to get out of control.”