Helicopter pilot Mark Robinson was giving a flight lesson along the Orange County coastline Thursday when something made him do a double take.

Sharks. Everywhere. About a hundred of them.

“I thought to myself ‘I hope there’s no one in the water,’” he said after spotting the sharks in shallow water in Seal Beach near the San Gabriel river inlet. “I didn’t know what kind of sharks they were.”

He took a closer look, and saw they were leopard sharks – thought to be harmless, unless provoked.

Robinson, founder of Revolution Aviation, said there were two pods. He first saw the sharks during an early morning flight at 8:20 a.m. Thursday, then did another flyby at 7:20 p.m. as the sun went down, and the sharks were still hanging out.

There were no beachgoers in the area, he said.

“It was amazing,” he said.

A fly by Friday showed no sign of the sharks, which seemed to have moved on from the area.

Seal Beach and surrounding areas have had plenty of shark activity lately, with great white sharks hanging around the coastline longer than usual in recent years, according to experts, possibly because of warmer El Niño-related waters.

Chris Lowe, director of the Shark Lab out of Cal State Long Beach, said researchers have spotted the leopard sharks regularly along Seal Beach, Belmont Shore and Catalina in recent weeks.

Leopard sharks in the past few years haven’t gathered in big groups like this because the water offshore has been warm due to El Niño conditions. But with the recent cooling of water temps, pregnant females are gathering in shallow waters that have been warmed by the sun.

Leopard sharks give birth early spring, then start a new gestation cycle that can last 10 to 12 months. They are generally 4 to 5 feet long.

“We know that we’re weaning,” Lowe said. “I refer to it as the El Niño hangover.”

Leopard sharks can be found as far north as Humboldt Bay, but they don’t gather in large groups like this north of Santa Barbara, Lowe said.

They aren’t dangerous to humans, he said.

“The only time anyone should be scared is if they are a worm or a clam,” he said.

Lowe and his students have also been keeping a watchful eye on the great white activity off the coast, with more sightings in recent years than ever before, according to experts and longtime lifeguards. This summer, however, has been quieter than other years, Lowe said.

“This summer, we haven’t had aggregation of (great white) pups like we’ve had in the past.,” he said.

There have been more reports of pups up near Santa Cruz. Locally, while there have been fewer juveniles, there have been more reports of adults and subadults – sharks in the 10-to 11-foot range – than ever before, he said.

“As it cools down, the pups will migrate to Southern California. In the next month, they will probably make their way through Southern California on their way to Baja for the winter there,” he said.

He’s not sure if the recent behavior change is because of El Niño or affects of global climate change, or if this is the new normal.

“Every time I feel like I have things figured out and we have a pattern, something breaks,” he said. “This year was a weird year.”

Register reporter Joshua Sudock contributed to this report.

Contact the writer: lconnelly@ocregister.com

More about leopard sharks

Leopard sharks have dark bars along their dorsal surface and body. They are known to form large schools and eat crabs, shrimp, clams, octopus, anchovies, bat rays and other small fish. They are found from Oregon to the Gulf of California and Mexico.

The leopard shark is typically found in shallow enclosed muddy bays – usually entering as the tide rises and departing as the tide retreats. The species favors sand flats, mud flats, and rocky bottom areas near reef sites and kelp beds.

Source: SeaWorld