Warning signs posted at Torrey Pines State Beach after shark ‘bumps' swimmer

A swimmer off the coast of San Diego had a close encounter with a large shark on Tuesday.

According to Jorge Moreno with Cal State University Long Beach's Shark Lab, shark-warning signs were posted off Torrey Pines State Beach after the swimmer encountered what Moreno described as a 7-8 foot shark.

The shark was spotted at about 10:30 a.m. in the water near Lifeguard Tower 5, according to Moreno, who was not sure how far out to sea the swimmer was when it happened.

NBC 7 also discussed Tuesday's sighting with Shark Lab director Chris Lowe, who said he spoke with lifeguards about the incident.

"It's not that uncommon," Lowe said. "It's the beginning of shark season in Southern California, so white sharks are starting to show up."

Lowe said many of the sharks off San Diego's coast migrated away during the winter because the water was pretty cold. Many of the white sharks in San Diego waters have returned to use the area as a nursery habitat, Lowe said, since it's a safe place and a warm place. Bonus: There are lots of stingrays for them to eat.

"Now that the water temperatures are warming up," Lowe said, "we're seeing sharks again."

The swimmer's interaction with the shark is unusual, Lowe said, however.

"It's actually really rare for sharks to actually bump swimmers or surfers," Lowe said. "We have lots of sharks, and we have lots of people, usually in close proximity to each other all summer long, and the sharks tend to ignore people."

Lowe speculated that the shark that bumped the swimmer may have been startled or, possibly, was just curious and checking the person out.

California averages three shark attacks on humans per year, according to Lowe, and 97% of those are attributed to white sharks, but, compared with Florida, where the average number of bites per year is 39, that figure is "pretty low," he said.

"They're always out there," Lowe said, but "go enjoy the beach, enjoy the water, know that these animals are out there. Remember that there are also stingrays out there, and stingrays hurt about 10,000 people a year in California."

The peak of shark season off San Diego is usually July or August, the scientist said, but it's been prolonged into September, likely due to climate change.

The warning signs put up Tuesday, which will remain up for about 24 hours, were posted near Towers No. 2, 5 and 7, as well as near the boundary where the state beach borders Del Mar City Beach.

"California State Parks would like to remind visitors that sharks are an important part of the coastal ecosystem and that interactions between humans and sharks are rare along the Southern California coast," officials said.

People can click here to learn more about the Shark Lab.

With reporting by NBC 7's Kasey Trombley — Ed.