Moving sea otters, possibly to San Francisco Bay, is doable, the report says

Relocating sea otters to places in Northern California and Oregon where they haven’t lived for generations, including possibly using helicopter rides to move a few dozen of them from the Monterey Bay area to San Francisco Bay, is doable and could help. to expand populations of endangered marine mammals.

But there are delicate economic issues that need to be resolved first, first of all how it might affect commercial fishermen who catch species like the Dungeness crab that sea otters also like to eat.

That was the conclusion Wednesday from a new report from the U.S. Fish and Wildlife Service. The 200-page study, requested by Congress, has given impetus to the growing idea among many marine biologists and conservationists that the best way to help restore endangered sea otters is to spread their numbers over a larger area. wide of the west coast.

“If we were to rely on expansion of the natural range, it would be a long, long time before sea otters are able to regain their historical range,” said Michele Zwartjes, study co-author and field supervisor for US Fish. and Wildlife Service in Oregon.

“We have recommended very small targeted reintroductions – maybe 100 or 200 sea otters in 30 years, not thousands,” he added. “We anticipate that any impact would be very localized over a very long period of time.”

Similar relocation efforts have occurred with California condors over the past 30 years. Scientists bred endangered birds in zoos, then released them in Big Sur, the Grand Canyon and other places, steadily increasing the number of condors.

But condors eat dead deer and dead sea lions. Otters eat live animals like Dungeness Crab, a $ 51 million annual commercial catch in California.

“They really need to think about this,” said Mike Conroy, executive director of the Pacific Coast Federation of Fishermen’s Associations in San Francisco. “These ecosystems have evolved without the presence of sea otters for 200 years. If this is not thought of, it could be disastrous. ”

An increase in the number of sea otters in southern Alaska over the past few decades has led to a decline in Dungeness crab catches there. There are over 90,000 otters in Alaska. Along the central coast of California, there are about 3,000 of them.

The report does not approve the relocation of otters, most of which currently live in California between Santa Cruz and Morro Bay. More studies would be needed, officials from the Fish and Wildlife Service said, to choose the best locations and find out exactly how otters would impact local fish economies, including crabs, clams, abalone and other shellfish.

Some areas that have been considered are San Francisco Bay, the Sonoma Coast, and Drake’s Estero Lagoon in Marin County.

The idea is to expand the genetic diversity of otters and reduce the risk that a major event such as an oil spill wipes out a large chunk of the sea otter population by moving small numbers so they can re-establish populations.

Historically, there were around 16,000 sea otters along the California coast. But they were relentlessly hunted in the late 1700s and early 1800s by Russian, British and American fur traders for their skins.

Many lived in San Francisco Bay. But with the gold rush, they were almost gone. They were feared extinct until the 1930s, when about 50 were discovered in the remote bays of Big Sur. Protected by the Endangered Species Act in 1977, they began a slow comeback.

Over the past decade, however, sea otters have not been able to expand north beyond the Pigeon Point area in San Mateo County due to attacks by great white sharks. As climate change warmed the waters, younger great white sharks moved north to the area from Southern California.

The goal is to get the otters around the shark hotspot so they can re-establish themselves further up the Northern California coast, the researchers say.

“We’re seeing more shark bites than we’ve ever seen before,” said Aimee David, vice president of ocean conservation for the United States and California at the Monterey Bay Aquarium. “They are not the prey of sharks, but as more and more sharks come north due to changes in temperature conditions in the ocean, these sharks mistake otters for prey, they bite them and often the bites are fatal.”

Aquarium research has helped show that although otters are known to live in seaweed beds in the ocean, they can also thrive in bays and lagoons. Beginning in 2001, aquarium scientists began taking young otters that had been separated from their mothers in the ocean, having them breed females in captivity, then releasing them at Elkhorn Slough in North Monterey County.

In the beginning, there were 20 wild otters there. In 15 years, 37 more captive raised have been released and Elkhorn Slough’s population has jumped to between 100 and 150. This could happen in San Francisco Bay.

“San Francisco Bay could support a large number of sea otters given its size and potential as a habitat,” said Jessica Fujii, head of the aquarium’s sea otter program. “That doesn’t mean it’s the best location, but it’s an area to consider.”

The U.S. Fish and Wildlife Service will begin hosting public gatherings over the next year in coastal communities in Northern California and Oregon to discuss the matter with residents, Zwartjes said. If suitable locations are found, he said, the service will conduct a detailed economic study and a comprehensive environmental study before giving the green light.

“If we were to reintroduce sea otters, where would we do it with the greatest chance of biological success?” she said. “And how could we minimize local impacts on fisheries?”


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