They are one of the city's most popular tourist attractions. But hundreds of sea lions have disappeared from San Francisco's Pier 39 in the past month.
Now a couple of thousand California Sea Lions have turned up off the Oregon Coast. Marine experts believe they are the ones that are missing from San Francisco Bay.
"We're seeing the sea lions coming up this way from California because of the feeding. If the cold water fish move north to find colder waters, the sea lions have to eat and they follow the fish wherever they go," said Sea Lion Caves General Manager Dan Harkins.
The California Sea Lions can be identified by the sound they make. They bark rather than growl like the local Stellar Sea Lions from Oregon.