Decline of Sea Otter Population for 4th Straight Year Baffles Biologists

Federal and state biologists were hoping for good news when they set out in boats and airplanes to count California sea otters, but they found instead that the population has dropped for the fourth straight year.

The recently completed count shows that the otter population off the Central Coast has dwindled to 2,090, down 12% from the 1995 high for this century. If the population drops to 1,850, the California sea otter could be considered closer to extinction and listed as “endangered” under federal law.

Experts fear that the sea otter decline is carrying some indecipherable message about the marine environment.

“They are the top predator in that whole near-shore ecosystem,” said Jane Hendron, education specialist with the U.S. Fish and Wildlife Service. “We have to ask ourselves, is something out of balance? Is this a water quality problem?”

Infections are the biggest killers of otters, and biologists worry that their immune systems are being damaged by an unknown contaminant, making them more susceptible to disease.

Especially worrisome is the discovery that the population of adult and adolescent otters--the breeders of the future--dropped 5% in just one year.

“The population did try to respond by producing more pups. But 80% to 90% of those pups aren’t going to survive,” said Dave Jessup, senior veterinarian with the California Department of Fish and Game. “We’re as little as one bad count away from a crisis.”

Scientists found that sea otters are spreading out from their home base on the Central Coast--many moving south into the Santa Barbara area--as their numbers are dropping. “They may be spreading out because they face severe shortages of food,” Jessup said. “Maybe that is making them susceptible to disease.”

Two of the animal’s more common diseases, brain swelling caused by cat feces and bacterial infections, can be directly linked to sewage in the ocean, he said.

Sea otters once roamed from the Japanese islands, north along the Russian coast, across the Bering Strait and down the West Coast of North America to Baja. Hunted almost to extinction, the northern sea otter population of Alaska has recovered well in this century.

The southern sea otter, also called the California sea otter, is a smaller subspecies genetically different from its northern neighbor. Population growth was steady throughout the 1980s and early 1990s, reaching a high of 2,377 in 1995. The high swells and food shortages caused by the El Nino weather pattern of 1997-98 killed otters, but biologists note that the otter decline has lasted for four years of good and bad weather.

Otters eat 15 to 20 pounds of abalone, sea urchins, clams and crab a day to support a metabolic rate four times as fast as a human’s. They must groom constantly to keep air bubbles in their fur to stay warm.

During the count that ended in June, biologists tracked sea otters from Point San Pedro near Pacifica in the north, south to Carpinteria below Santa Barbara. The occasional male spotted off the Palos Verdes Peninsula is considered more a bold adventurer than potential settler.

The animal’s move into the Santa Barbara area in the past three years conflicts with a federal “no otter” zone set up to protect the catch of shellfish fishermen around the Channel Islands.

In 1987, federal officials prepared a plan to trap and move all otters in the area below Point Conception near Santa Barbara to Morro Bay and other points north. In return for getting rid of the predators, officials persuaded fishermen to accept a plan to relocate a smaller group of otters to San Nicolas Island, one of the outer Channel Islands. The purpose was to create a second, healthy colony of otters in the event of an oil spill or other catastrophe.

But many otters simply swam back to their home range. Others died from stress. The U.S. Fish and Wildlife Service now wants to declare the 1987 agreement a failure.

The agency transplanted 139 otters to San Nicolas Island, but only 21 were there in May. In February, experts counted 153 male otters living below Point Conception. That population drops as the males retreat north each summer to mate, but there has been a steady march south.

Many fishermen feel betrayed.

“Maybe one-fifth of the area we work, between Point Conception and Santa Barbara, has been taken over by the otter already,” said Bruce Steele, a Santa Barbara sea urchin diver. “One-fifth of our turf, we’ve pretty much given up.”

Jessup conceded that otters are “chain saws in a fur coat” when it comes to shellfish. Steele agreed.

“In fish management, you try to leave behind enough so the animal can breed successfully. With sea otters you can’t do that,” Steele said. “They come in and take over.”

Steele and other fishermen contend that there is no crisis, that the otter has simply reached carrying capacity along the coast as part of the natural process.

Biologists, however, say there is good reason to be alarmed and that they fear the population could continue its inexplicable drop. They find sad irony in the fact that the American bald eagle will come off the endangered species list as the California sea otter moves closer to extinction.

“The big news was that bald eagles are recovering,” said federal biologist Carl Benz. “The big news here is that the sea otter seems to be getting worse.”

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Thinning Out, Spreading Out

Even as the number of sea otters along the California coast has declined, the animals have expanded their range over the years. Experts speculate that otters are on the move because they are starving and searching for food.