Sea lions’ arrival 27 years ago marked at Pier 39

January marks the 27th anniversary of sea lions colonizing a small dock on San Francisco’s Pier 39. To celebrate, the Aquarium of the Bay held free walking tours this weekend for people who wanted to see the blubbery pinnipeds up close.

The sea lions first began plopping onto Pier 39’s K-Dock in October 1989, shortly after the Loma Prieta earthquake. By January, the barking sea mammals had taken it over. Marine mammal specialists recommended that the creatures be allowed to stay in their newfound resting spot — and they’ve been there ever since.

No one knows for sure why the sea lions made the dock home, but many speculate the earthquake had something to do with it.

“It’s strange and neat that they showed up after the earthquake,” said San Francisco resident Paul Foppe, 41, who was at Pier 39 this weekend to see the sea lions. “You don’t normally think of anything good coming from tragedy, but the sea lions were a nice surprise.”

During a break in the rain Sunday, a dozen people took one of the sea lion tours at Pier 39. The free event was one of many scheduled for this year celebrating the 39th anniversary of the Pier 39 complex.

Tour guide Patrick Sysiong described the difference between sea lions and other pinnipeds, explained why the large mammals pile so close together on land — they’re trying to keep warm — and detailed some of the threats facing sea lions in the San Francisco Bay.

There were roughly 100 sea lions on the wooden docks Sunday afternoon, most of them male.

The rain may have deterred some, but it didn’t appear to thin the crowds too much, according to Sue Muzzin, spokeswoman for Pier 39. “When we know there will be inclement weather we hold the tours inside the Sea Lion Center,” Muzzin said.

Yulia Hernandez, 30, brought a visiting family from Russia to the sea lion tour to see the barking animals. “It’s entertaining to watch them fight, sleep, do funny stuff,” Hernandez said. “I could spend half an hour just looking at them.”

While it’s a mystery why the sea lions showed up at Pier 39 nearly three decades ago, the protected docks provide an ideal living situation for the creatures.

Unlike at Seal Rocks — a cluster of small rock islands near the Sutro Baths also popular for viewing sea lions — great white sharks seldom come into the bay, and the waters are calm.

“It was probably totally random” that the sea lions chose to live at Pier 39, said Ryan Jones, an interpretive specialist at the Aquarium of the Bay. “Some sea lions prob- ably found it, their ‘buddies’ followed them, and more and more kept coming.”

“It’s entertaining to watch them fight, sleep, do funny stuff. I could spend half an hour just looking at them.”

Yulia Hernandez, who brought a visiting Russian family to see the sea lions at Pier 39

Photos by Scott Strazzante / The Chronicle Visitors on Pier 39 in San Francisco watch a group of sea lions. The animals took up residence on the docks after the Loma Prieta earthquake in 1989.

A sea lion swims on its back near Pier 39, where events, such as sea lion tours, are scheduled for 39 weeks this year, ending with a birthday bash in October to celebrate the Pier’s 39th year.