Great White Sharks Meet Humans at California Beaches 'Nearly Every Day'

Great white sharks and humans are coming close to one another "nearly every day" at certain California beaches with increasing regularity, scientists have found.

But despite these frequent encounters, researchers did not document a rise in shark bites in these locations, according to a study published in the online journal PLOS One.

The authors decided to conduct this research because of indications that the great white shark population that roams the California coast is growing. This population of sharks uses Southern California as a nursery habitat where young individuals spend their first years of life.

"They are largely a threatened species globally, so seeing the population recover is a good thing," Patrick Rex, a graduate student in the Department of Biological Sciences at California State University, Long Beach, told Newsweek. "Southern California is also one of the most popular places to use the ocean for human recreation, which is also exponentially increasing."

He continued: "So there has been worry that an increase in this shark population may lead to more shark bites. To really assess this, we needed information that we surprisingly did not have before this study. Primarily, how often are these sharks at the same beach at the same time as people, where are people and what are they doing in the water when they are there, and who is more likely to encounter these sharks?"

For the study, Rex used commercially available drones to survey the Southern California coast at 26 beach locations, from San Diego to Santa Barbara, between January 2019 and March 2021.

Rex scanned the beaches looking for people and juvenile white sharks at an altitude that allowed him to observe both without affecting their natural behavior. He then used this footage to quantify how much overlap there was between juvenile white sharks and people.

The study found that at certain locations where aggregations of juvenile white sharks formed, the daily "co-occurrence" of humans and these creatures—meaning incidents when they used the same beach areas—was 97 percent.

The co-occurrences were recorded primarily at two significant aggregation sites along the California coast, which were in Carpinteria and Del Mar.

Juvenile white sharks form aggregations for weeks to months at a time at popular beach recreation areas in California. These aggregations can involve up to 40 to 50 juvenile white sharks in an area that is only a couple of miles long, which presents a potential bite risk.

Because sharks and water users were consistently observed at aggregation sites in the same areas, often close to shore, the study's authors said there is a "high likelihood" that the creatures are encountering people frequently each day.

"The key findings from this study were that people and sharks are around each other nearly every single day, with increasing frequency, but we aren't seeing a rise in shark bite frequency on humans," Rex said.

The number of unprovoked shark bites across Southern California is extremely low. Since 2000, only around 20 unprovoked white shark bites in this region have been recorded.

"In two of the locations I studied, sharks were present for up to two years, with humans present almost daily," Rex said. "Not only were sharks at the same beach as people, they were using almost the exact same location along the beach. So we have near-daily encounters between people and sharks without incident. In fact, we saw surfers and sharks sharing the waves."

Outside of areas where the sharks formed aggregations, however, the authors found the opposite result.

"Outside of these aggregation areas, there is really a small presence of juvenile white sharks," Rex said. "We also found that outside of these aggregations sharks were significantly farther offshore, meaning they are less likely to encounter people."

Rex said he and his colleagues hope the study will help to reduce fears about sharks along the U.S. coast.

"Juvenile white sharks are still very large predators, but it seems as long as we leave them alone they will leave us alone," he said.

Since the humans in the study were predominantly unaware of juvenile white shark activity in the beach areas they were using and were not intentionally interacting with the creatures, the risk of bites was low despite sharing the same spaces, the researchers said.

"It's been largely assumed that areas with high overlap between sharks and people will lead to an increase in bites," Rex said. "However, our data shows that may not be the case. In fact, our study shows that humans and sharks were at the same beaches, every day, for nearly two years without incident. Humans aren't on the menu for sharks, so it seems that we can co-exist."

The latest research could have other potentially significant implications besides shedding light on human-shark interactions, the authors said. For example, they also observed sharks across the entire study period, even throughout the winter.

"Historically, juvenile white sharks would migrate to Mexico when our waters got too cold in late autumn or winter," Rex said. "Potentially, climate change and warmer waters could be changing, and the juvenile white shark nursery in California could even be expanding. That is just a hypothesis, though, but we are starting to see the shifts."