The dark spots in the water are leopard sharks. Helicopter news crew captured the image when flying over La Jolla Shores.
More than 800 of leopard sharks were seen swimming at La Jolla Shores on Friday afternoon.
Helicopter pilots captured video of the docile creatures swimming close to the coastline alongside swimmers and kayakers.
The sharks usually swim near La Jolla Shores every summer, but there were more Friday afternoon and they were swimming closer to the shore than usual, said Nigella Hillgarth, executive director with the Birch Aquarium at Scripps.
All of the sharks are pregnant females. They swim closer to the shoreline because it makes them give birth faster to their pups, Hillgarth said.
"They're perfectly safe," she said.
Leopard sharks can grow up to 6 feet when fully matured. They are called "leopard" sharks because the spots on their back resemble that of a leopard.
The sharks are not a threat to humans. In fact, many snorkelers come out to watch them swim every year.
Robin Teague of Temecula saw one of the leopard sharks while kayaking and snorkeling in the area on Friday afternoon.
"I just happened to see a shark go by me, it scared me," she said.
Teague saw a leopard shark three times while she was out in the waters.
"Enjoy them enormously," Hillgarth said. "I think we're incredibly lucky to have beautiful large, harmless sharks next door to us."