(Photo : Photo by Justin Sullivan/Getty Images)
Sea Lions cut up on Pier 39 in San Francisco Bay. They're gathering just now in record numbers.

After a number of rough years California sea lions appear to be coming back strong, given the massive numbers of the animals in San Francisco Bay.

More than 1,000 sea lions were tallied in a single week at Pier 39 at Fisherman's Wharf, a popular tourist destination in San Francisco. It's the biggest group of the marine mammals seen at the pier in the last 15 years.

"It's really a phenomenon," said Pier 39 harbormaster Sheila Chando. "It's like a National Geographic photograph right now."

Experts say the turnout is evidence of a healthier ecosystem in San Francisco Bay after sea lion numbers were battered by deaths from ingesting toxic algae and starvation as fish fled their territory to seek cooler waters amid climate change.

They sea lions are currently being enticed by huge numbers of anchovies and herring in the bay from the nearby Farallon Islands. They'll will feast on the fish and spend days basking in the California sun before heading south to mate.

"We've landed right in the middle of a perfect storm of circumstances," Chandor told SFGate. "We're seeing a feast."

"When they're together in these kind of numbers, they energize each other," Chandor noted. "They're just all fat and happy."