SANTA CRUZ — The frenzy off the California coastline this spring has felt like a long-running loop of “Shark Week.”

In April, a shark bit a San Diego mom of three who was swimming off San Onofre State Beach.

Last month, San Clemente officials closed beaches after more than two dozen white sharks were spotted by air.

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Shark hunt: The search for whites on Monterey Bay does not disappoint That followed the circulation of alarming internet videos of a shark charging a kayak, sending the paddler flying into Monterey Bay.

Then, on Thursday, lifeguards evacuated Capitola sixth-graders from the water at New Brighton State Beach when spotting what they believed was a white shark swimming near shore during an end-of-school field trip. Social media posts of shark sightings from the Cement Ship in Aptos to the Santa Cruz Harbor have become a regularity.

As summer heats up, calling thousands of visitors to the Bay Area’s world-class shoreline, marine biologists are trying to mitigate irrational fears over increasing sightings of white sharks.

“This is the new reality,” said Christopher G. Lowe, director of the Cal State Long Beach Shark Lab. “People are going to have to learn to share the waves.”

Although white sharks tend to inhabit the state’s most populous areas — adults are concentrated around San Francisco whereas juveniles mostly are found from Los Angeles to San Diego — relatively few attacks involve humans.

In the past 50 years there have been about 12 fatalities and a little more than 80 recorded interactions in California waters, reported Salvador Jorgensen, a Monterey Bay Aquarium research scientist.

“That is one mortality every five years,” he said.

But sightings and interactions with the fish have fueled a “Jaws”-like panic for some beachgoers while attracting morbid interest in a predator with a conical-shaped snout, beady eyes and those infamous serrated, triangular teeth.

The white-bellied descendants of prehistoric creatures have returned to the spotlight 42 summers after Steven Spielberg introduced his sinister and vengeful fish to moviegoers.

The El Nino effect

Instead of a ghastly picture of shark-infested waters, however, researchers have seen a shift in habitats they attribute to the El Niño weather phenomenon that has pushed warmer currents north. Jorgensen, the author of “Sharks: Ancient Predators in a Modern Sea,” said smaller white sharks need warmer water until they mature.

“So water temperature plays a huge role in where and how many smaller white sharks are seen,” he said.

Spotting juvenile white sharks in Monterey Bay might become common if the seas experience El Niño conditions more regularly because of global warming.

Lately, marine biologists and tourists have been drawn to the action around the Cement Ship at Seacliff State Beach in Aptos. In the past three years, researchers have identified juvenile sharks patrolling the waters around the sunken ship, an event that had not been recorded before that.

“They sit out there and act like they just had a big turkey dinner and want nothing to do with anything,” said Chris Gularte, chief pilot for Watsonville tour operator Specialized Helicopters.

Gularte, 45, has seen no fewer than 20 sharks on any given day that he has flown over the area in the past month.

Gularte and others have reported frequent juvenile sightings at nearby New Brighton as well.

The baby white sharks found in these new locations are part of a larger picture of ecosystem changes attributed to El Niño. Two years ago, Southern Californians discovered venomous sea snakes at their doorsteps for the first time in three decades. Marine scientists said the yellow-bellied sea snake followed warmer ocean currents to the California coast. Those currents also brought pelagic red crabs and hammerhead sharks.

Scientists believe white sharks give birth off Baja California, and the pups nurse in the Mexican and Southern California waters.

The population could be on the rise

But over the past 15 years, Lowe has seen a steady increase in juvenile sharks in Southern California. He remains optimistic it is evidence of a population spurt, although a parallel increase in adults has not been documented to the north.

“You can’t have more babies without having more mommies,” Lowe said.

White sharks have been protected in California waters since 1994 although they don’t have any natural enemies other than humans. According to the California Department of Fish and Wildlife, it is believed the state’s population of adult white sharks numbers fewer than 100.

Researchers such as Jorgensen, who has conducted annual surveys of adult white sharks since 2006, can’t confirm a population increase, although they are cautiously optimistic for the simple fact the white shark’s primary food sources — elephant seals, sea lions and harbor seals — are thriving.

Lowe speculates there is a habitat shift among mature fish as regular feeding grounds get crowded.

“These teenage and adult white sharks haven’t been able to make a living at the Farallons and Año Nuevo,” he said of two major feeding grounds. “They are looking for new places to forage in the fall. I think that place is Southern California.”

Such a shift could change the equation when it comes to human-shark encounters.

Most incidents have occurred in a 150-mile zone known by Northern California surfers as the Red Triangle — yes, red, as in the color of blood. The sharky region stretches from Monterey to Bodega Bay, out to the Farallon Islands. Put another way, only 17 of the 100 recorded shark attacks on humans in California in the past 63 years occurred south of Point Conception (Santa Barbara County), according to the state Department of Fish and Wildlife.

Demystifying the king of the sea

Such a collection of data helps engender deep-seated anxiety while placing white sharks with grizzly bears and saltwater crocodiles as mythic predators.

“The ‘Jaws’ narrative is just stuck with us,” said Jorgensen, who has a doctoral degree in ecology from UC Davis.

But researchers’ work provides a substantive counterpoint. In a paper published in Frontiers in the Ecology and the Environment, Jorgensen and colleagues found the risk of a white shark attack in California had decreased by 91 percent from 1950 to 2013.

Sean van Sommeran, founder of the Santa Cruz-based Pelagic Shark Research Foundation, downplayed the fears as shark sightings have increased this spring.

“Guess what marine animal hospitalizes more people in California than all others combined?

“Stingrays,” said van Sommeran, a self-described shark field operative without a science degree.

Most documented attacks on humans off the California coast have occurred between August and November. This is the time adults feast on seals and sea lions, often near river mouths where the salmon runs attract other fish.

The beasts can grow to 20 feet in length and as much as 4,600 pounds to present a terrifying portrait. Lowe and other marine biologists realize they shoulder the responsibility to teach the public as much as they can about white sharks in order to help preserve the animal.

It starts with calling the fish a white shark, leaving out the “great” that often is used in popular culture.

The Cal State Long Beach professor recalled how whales were demonized 100 years ago, but now whale-watching tours are a thriving business along the West Coast.

“It’s harder to imagine that image makeover for sharks,” Lowe said, “but it’s happening.”