They're lounging, biting each other and generally making a ruckus in numbers not seen in more than a decade. San Francisco's famed Fisherman's Wharf district is seeing a surge in sea lions. First appearing at Pier 39 after the 1989 earthquake, the sea lions have become a well known tourist attraction. The number of sea lions crashing at the pier fluctuates over the seasons. On most days more than a hundred can be seen. But this week, Pier 39 has counted more than one thousand sea lions, the most they've seen there in 15 years. The barges the sea lions lounge on are designed to hold significant weight. But officials admit this current surge is testing their limits. Biologists believe an unusually high number of anchovies in the Bay have attracted extra sea lions this Spring. The spike in sea lions is only expected to be temporary as they're just making a pit stop in San Francisco, refueling for food, as they travel to Southern California's channel islands for mating season. Shops and businesses around the area are hoping the sea lion surge will also result in a tourist shopping spree, attracting more visitors to the area.