Great whites are far more prevalent than expected on the California coast • Earth.com
06-04-2023

Great whites are far more prevalent than expected on the California coast

Researchers at Cal State University have discovered that juvenile great white sharks are far more prevalent along the California coastline than previously assumed. This presence has shed new light on the reality of human-shark interactions and possibly on how climate change may be affecting shark migration patterns.

A two-year research project led by Professor Christopher Lowe, director of the Shark Lab and a professor of Marine Biology at Cal State Long Beach, relied on drone technology to observe more than two dozen beaches along the state’s extensive shoreline.

The study’s target demographic was juvenile great whites, aged between one and five years. To the researchers’ surprise, these young great whites appeared to be particularly concentrated in two locations: southern Santa Barbara County and central San Diego County.

The intriguing aspect of this finding was not just the unexpected frequency of the juvenile sharks in these regions but the nature of their interaction – or lack thereof – with humans. According to the results released last Friday, these aggregation sites often witnessed sharks and humans sharing the oceanic playground simultaneously 97 percent of the time.

Minding their own business

The notion of sharks circling in the same waters as surfers and stand-up paddle boarders might immediately bring to mind scenes from Steven Spielberg’s iconic film “Jaws.” Yet, the researchers emphasize that their observations provide a clear contrast to these sensationalized Hollywood scenarios. 

Rather than menacing predators, the young sharks “tend to mind their own business,” says Patrick Rex, a lab technician at the Shark Lab. The researchers frequently observed juvenile whites swimming within 50 yards of where the waves break, even coming within 10 feet of beachgoers – who were often unaware of a shark’s presence.

The important question that arises from these observations, Rex points out, is not about fear but about perception: “People think, ‘If I see a shark in the lineup (the area where waves begin breaking), I’m going to get bitten or I’m in danger.’ And what we’ve seen is that that’s not necessarily the case.”

During the entire period of the study, no shark bites were reported at any of the observed beaches. In fact, shark bites in California are quite rare, with the state Department of Fish and Wildlife documenting only 209 incidents from 1950 to November 2022.

New insights

This proximity to humans without any significant incident has led the scientists to theorize that these sharks have started to recognize humans as “not food.” Although this is not a definitive conclusion, given the complexities of understanding why sharks bite humans in the first place, it does offer a glimmer of insight into the nature of these majestic creatures.

These findings offer invaluable information to lifeguards, particularly those operating in these aggregation sites, to help ensure safe swimming and water recreation. The research also offers a fascinating window into the behaviors of young sharks, who tend to spend their time at these spots feeding on stingrays and small fish at the seafloor.

Interestingly, this research may also be offering insights into broader environmental shifts. The scientists noted that some of the sharks they were observing did not leave the California waters as they traditionally would when the colder seasons set in. 

Rex suggests that climate change and the resultant warmer waters might be causing this shift in migratory patterns. “It means that the sharks may not be making that long migration anymore,” he explained. However, he was quick to caution that this was an early hypothesis, with more data and time needed before firm conclusions could be drawn.

These intriguing findings emphasize the importance of continued marine research, the results of which not only bring us a deeper understanding of these incredible creatures but also of our role and responsibility in the delicate balance of our shared environment.

More about great whites

Great white sharks are the largest predatory fish in the world, with adults typically measuring 13 to 15 feet in length, although specimens exceeding 20 feet have been recorded. These sharks are known for their torpedo-shaped bodies, which allow for speed and agility in the water, and their iconic white underbellies, which gives them their common name. Their back and sides are typically a slate-gray color, providing an effective camouflage in the water.

Great whites have a global distribution, and are primarily found in cool, coastal waters. They have been observed in waters with temperatures ranging from 54-75°F (12-24°C), which means they can be found in seas off the coasts of the United States, South Africa, Japan, Oceania, Chile, and the Mediterranean, among others.

Great white sharks are apex predators, meaning they have no natural predators aside from the occasional killer whale. Their diet mainly consists of fish, seals, small cetaceans (like dolphins), sea turtles, sea birds, and even other sharks. They are known for their “breaching” behavior when hunting seals, propelling themselves out of the water in an impressive display of power and agility.

Despite their reputation, attacks on humans are relatively rare and are usually a case of mistaken identity, such as a shark confusing a surfer for a seal. Contrary to popular belief, humans are not a preferred food source for these sharks.

Great whites are ovoviviparous, which means eggs develop and hatch within the body of the female and are born live. Little is known about their breeding habits, but pups are generally around 5 feet long at birth and are immediately self-sufficient.

These sharks are migratory and can travel thousands of miles. A famous shark named Nicole traveled from South Africa to Australia and back in nine months, a journey of over 12,000 miles.

Unfortunately, great white sharks are currently listed as vulnerable by the International Union for Conservation of Nature (IUCN). They face threats from hunting (for their fins, teeth, and as trophies), accidental catch (bycatch) in fishing gear, and pollution. Efforts are being made to protect these majestic creatures and ensure their survival for future generations.

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