San Francisco's vanishing sea lions baffles experts

Since Oct. 23, when volunteers with Sausalito's Marine Mammal Center counted just over 1,700 of the pinnipeds sprawled out on the docks at Fisherman's Wharf, the number of sea lions has plummeted.

Tuesday afternoon, as holiday visitors and tourists swarmed the pier for magic shows, ferry rides and funnel cakes, the only empty spot was the network of docks reserved for the federally protected sea lions.

A half dozen of the slippery sea mammals swam around behind the breakwall, but only hauled out at adjacent docks busy with boat traffic where men with hoses quickly persuaded them to jump back into the frigid water.

"I've been coming here for 21 years and every time it's been packed with sea lions," said Arsalan Ziazie, 63, a writer from Los Angeles visiting his daughter in San Francisco. "It's very strange."

Biologists concur. Sea lion numbers can fluctuate due to changes in food supply and water temperatures. But so far, scientists haven't found any evidence that the mammals' prey is diminished overall or that the warming ocean waters of El Niño would decrease, rather than increase, local populations.