Sharks as big as small yachts spotted off California coast after 30-year absence

Basking sharks are large and gentle and in April 2019 they started to reappear in California waters after a 30-year absence. (photo: Gregory B. Skomal / NOAA) Basking sharks are large and gentle and in April 2019 they started to reappear in California waters after a 30-year absence. (photo: Gregory B. Skomal / NOAA) Photo: Gregory B. Skomal / NOAA Photo: Gregory B. Skomal / NOAA Image 1 of / 28 Caption Close Sharks as big as small yachts spotted off California coast after 30-year absence 1 / 28 Back to Gallery

A species of enormous sharks, some as long as small yachts, have been frequently spotted off the coast of Southern California after all but vanishing decades ago.

But need not fear, basking sharks are often called "gentle giants" as they aren't aggressive and don't bite. Swimming with their mouths wide open and often near the surface, they are filter feeders, consuming tiny food such as plankton.

Cal State Long Beach Shark Lab Director Christopher Lowe tells the Ventura County Star it's been 30 years since basking sharks have been seen in the area in large numbers.

After whale sharks that can reach 60 feet long, basking sharks are the second-largest known shark species, growing to be 30 feet long, though the ones seen locally have been in the 18- to 25-foot range.

Lowe says there's been a spate of sightings off Ventura and in Santa Monica Bay, where they were a common species years ago. The basking sharks started showing up in April and at this point it's unknown whether their spring appearance is a sign of a comeback.

"We don't have enough data points nor enough basic information to say what is going on with their population with any confidence," says Heidi Dewar, marine biologist with the National Oceanic and Atmospheric Administration (NOAA). "Basking sharks are California's largest shark and yet most people have never heard of them."

While not officially listed as endangered under the U.S. Endangered Species Act., basking shark populations have been greatly reduced due to commercial fishing.

"In the last few decades regulations have reduced fisheries mortalities but they are still at risk because their fins are very valuable for shark fin soup," says Dewar.

ALSO: Two separate videos catch close encounters with sharks in Humboldt County

Basking sharks once also frequented Monterey Bay and in July 2015 a huge school made a rare appearance to the delight of marine biologists.

"I have been going on the ocean for 20 years and have only seen four basking sharks in my whole life," marine biologist Giancarlo Thomae told the San Jose Mercury News at the time. "Because of the rarity of these animals, it is extremely difficult for researchers to tag these animals, or study them."

If you spot a basking shark, NOAA asks that you email the agency at basking.shark@noaa.gov with information about the sighting to help track the species.

"If they do see them on the water they should be careful to avoid collisions by slowing down and not making rapid changes in speed or direction," says Dewar.

The Associated Press contributed to this story.