I don’t think we know yet.”. “They were in San Francisco Bay historically,” Rudebusch said. Paul Rogers has covered a wide range of issues for The Mercury News since 1989, including water, oceans, energy, logging, parks, endangered species, toxics and climate change. The aquarium has released dozens back into the wild, most notably at Elkhorn Slough, an estuary near Moss Landing full of tidal marshes, creeks and muddy channels — similar to San Francisco Bay. While he is hopeful that further research into reintroducing otters to the bay will show promising results, Boehm said more research and input from all stakeholders who use the bay is needed before a decision should be made. “It would essentially end up lifting the sea otter out of its endangered species status,” said Brent Hughes, assistant professor of biology at Sonoma State University and lead researcher in that study. The concept is still in the early stages. Now there are about 3,000 otters in California and sea otters are protected as a threatened species under the Endangered Species Act. In 1986, river otters were listed as an endangered species in Nebraska. Related Articles “It was spectacularly beautiful.”, When the Otters Vanished, Everything Else Started to Crumble. However, there are several emerging threats to this sensitive species. “There were so many of them, we couldn’t keep track.”. Changes yet to come will likely prompt the grazers to pick up the pace even more, the team’s analysis showed, barring sweeping change in carbon emissions. Over the last decade, however, the number of shark attacks on otters has grown. That’s because they eat crabs, which eat sea slugs, which in turn eat algae on eel grass. He doubts he will live to see the otters return. The Marine Mammal Center in the Marin Headlands partners with the aquarium in responding to reports of injured or malnourished otters and pups. Sorry, your blog cannot share posts by email. Repatriating otters could help reefs in the near-term, Dr. Rasher said, perhaps “buying us time to get our act together in terms of curbing global carbon emissions.”. Many of the species they eat, such as Dungeness crab, are prized by commercial fishermen. To quantify the damage, Dr. Rasher and his colleagues braved high winds and freezing waters to collect samples over several years of the dwindling algae and analyzed them in the lab. “These long-lived reefs are disappearing before our eyes,” said Doug Rasher, a marine ecologist at the Bigelow Laboratory for Ocean Sciences in Maine and the study’s first author. But met with weakened reef layers, urchins excavated chasms several millimeters deep — the equivalent of up to seven years of growth. The findings point to the importance of otters in the Aleutians, where the marine mammals act not just as predators, but protectors, maintaining biological balance through their voracious appetites. “Just seeing that trend is staggering,” Ms. Boyd said. But the otters basically disappeared in the 18 th and 19 th centuries, after being hunted almost to extinction for the fur trade. As they have disappeared, the rest of the local food web has started to crumble — a process that’s been accelerated and compounded by climate change, Dr. Estes and his colleagues report in a paper published Thursday in the journal Science. Of those, 31 stayed in the slough. Ultimately, the sea otters will show us if it is possible for them to re-colonize the bay. Since the 1990s, the Aleutian sea otter has been "functionally extinct," researchers said. But these hidden relationships might contain hints of remedies. Softened by warming and acidifying waters, the coral-like structures have quickly succumbed to the urchins’ tiny teeth, which can annihilate years of fragile algae in a single bite. Dungeness crab was a $51.8 million fishery last year, said Mike Conroy, executive director of the Pacific Coast Federation of Fishermen’s Associations in San Francisco. Aleutian sea otters have been in flux before. He was greeted by an ocean filled with furry faces. The research analyzed hazards — including large commercial ships, high-speed ferries, oil spills, fishing gear and toxins such as mercury. Dr. Estes suspects that starving orcas — perhaps deprived of their preferred whale prey by industrial whaling — have turned in desperation to the little mammals, which they can gulp down by the hundreds or thousands a year. “San Francisco Bay is a busy place with a lot of things going on,” said Rudebusch, lead author of the study. GET BREAKING NEWS IN YOUR BROWSER. Against the backdrop of climate change, the delicate underwater ecology of Alaska’s Aleutian Islands is hurting from declines in otters. The otters, whose population has stalled in recent years at around 3,000, are stuck. The areas with lowest risk are in the North Bay, including San Pablo Bay National Wildlife Refuge and China Camp State Park near San Rafael, the study found, and in the South Bay, particularly the Don Edwards National Wildlife Refuge. Giant otters, endangered top predators which live in Amazon river ecosystems, were nearly wiped out because of demand for their fur. Many lived in San Francisco Bay, but by the Gold Rush, they were all but gone. Every year, its scientists take in several orphaned sea otter pups whose mothers have died or been separated. “Will it result in negative impacts to other species? It’s a place they haven’t inhabited for nearly 200 years, but some fishermen might not be ready to welcome them back. They were feared extinct until the 1930s, when about 50 were discovered in remote Big Sur coves. Aleutian sea otters have been in flux before. “There are a lot of stakeholders and understanding the needs and concerns of all of those alongside the data and the concerns and the modeling of the scientists is going to be a really rich discussion.”. But there are many unknowns, from whether transplanted otters would stay in the bay to how they might handle a crowded area with 8 million residents. And they have flourished. In just a few decades, this bustling civilization has withered into a ghost town. “There’s a great interest in restoring this animal to an ecosystem that has been missing one of its key parts for more than 150 years.