Sightings of dorsal fins piercing the surfline along San Diego’s coastline are common this time of year. The mostly harmless juvenile great white sharks are attracted to the high abundances of fish, stingrays and warming waters, said Andrew Nosal, a marine biologist at Scripps Institution of Oceanography.
“And we should expect them to be around to late fall, even into early winter,” said Nosal, who studies shark behavior and ecology.
The 5- to 10-foot-long sharks migrate to the region’s 70 miles of coastline every year in late spring. The pups return to Baja starting around November.
“Occasionally we do have larger adults that pass through,” Nosal said. “But once they start maturing at around 10 feet we tend to see them hanging out in colder water, and they tend to start feeding on marine mammals like seals and sea lions.”
Several sightings this year along Southern California have led to beach closures and warnings. Lifeguards at Silverstrand State Beach warned swimmers last Thursday to stay out of a stretch of ocean after an 8-foot great white shark was spotted near the shore.
Last month, lifeguards warned of more than a dozen great whites at Capistrano Beach in Orange County. In mid-May, harbor patrol officers in Dana Point spotted four great whites at the surf line. In April, a Vista woman was bitten by a great white as she swam off San Onofre State Beach.
Increased sightings of the ocean’s top predator can be attributed to a rising population, said Nosal. An estimated 2,400 great white’s are thriving along the California coast.
“In California, white sharks have been protected from commercial and sportfishing since 1994,” Nosal said. “And their food source, at least as adults — marine mammals — they’ve been protected federally since the 1970s. So the two of these things combined have led to a very strong recovery in our white shark populations.”
Another contributing factor is more people swimming and surfing, equipped with GoPros, Nosal added.
Nosal said great whites, along with the other shark species, including makos, leopards and threshers, help to maintain San Diego’s balanced and healthy ecosystem.
“We shouldn’t be necessarily afraid that there’s all these sharks in the water,” Nosal said. “We should be excited because it means that we’re doing something right. We’re protecting them, we’re protecting their habitat.”
The two main population centers for adult great white sharks are the Farallon Islands off of San Francisco and Mexico’s Guadalupe Island.
Great white shark attacks off San Diego are rare, Nosal said. Fewer than 20 attacks have occurred in the past 70 years. The latest fatality happened in 2008 off Solana Beach in North County.
