SF's Biggest Sea Lion Gathering in Years is Broken Up by Dock Work

Last week, more than a thousand sea lions sunned on the docks at San Francisco’s Fisherman’s Wharf, forming the largest herd in over a decade. On Tuesday, though, the area was noticeably devoid of their barks.

According to Sue Muzzin, vice president of public relations for Pier 39, the sea lions were temporarily spurred away by marina staff tightening bolts on multiple floating docks as part of routine maintenance work — though it’s possible all that extra weight over the last week put more wear and tear on the docks.

“The sea lions jump into the water, they don’t freak out, they’re used to this,” Muzzin told KQED. “It’s a regular routine maintenance check that we always do. And — there’s a little bit more stress on the floats these days.”

By Wednesday morning, Pier 39’s live webcam showed the sea lions back to their normal behavior, though in slightly lower numbers than last week.

The pier typically hosts between 300 and 400 sea lions in the winter and up to 700 in the summer, harbormaster Sheila Candor told the Associated Press. Last week’s surge to over 1,000 is the highest recorded number at the site in the last 15 years.

Why did so many pinnipeds decide to take a pit stop at Pier 39 this year? A large school of anchovies swimming by the Farallon Island, it seems.

The San Francisco Bay is often a rest stop for male sea lions migrating south for summer’s mating season in the Channel Islands, according to Adam Ratner, the director of conservation engagement at the Marine Mammal Center in Sausalito.

“Pier 39 provides a good place to rest, relax and take in the sun, and it’s just a quick swim from where there’s lots of yummy food,” Ratner said. “Right now, we’re seeing the animals kind of fattening up, getting ready for that breeding season.”

This year, they’ve found more food than normal close to the pier. Why there are so many anchovies present is a “great mystery,” the Marine Mammal Center’s team is still trying to figure out, according to Ratner.

“It could be that there are more fish, and that’s just great for the health of the ecosystem. Or, it could be that it’s not that there’s more fish, but the fish are in a different location than usual, closer to shore,” Ratner said.

The latter could be a bad sign — it might mean that more of the anchovy population is congregating in one place, increasing competition for food down in the Channel Islands, where the sea lions are heading.

“If there’s no food down there, we’re going to see a lot of animals that are actually struggling to find food and washing up on the shores sick and in need of help. But it’s hard to make that judgment call right now,” Ratner said.