Scientists fascinated by the growing population of great white sharks in Del Mar, California

Photo: Shutterstock


inertia

An exceptionally stable population of great white sharks in southern California has sparked scientific curiosity, public engagement, and markedly little violence toward swimmers and surfers.

A team of graduate students from California State University Long Beach’s Shark Lab began studying apex predators shortly after arriving in Del Mar, California in 2019. The population size and stability, which the team of experts has identified as an aggregation, is therefore.

Program director Dr Chris Lowe said The Coastal Press Group that the team has tagged just over 200 animals from the group, including “about 65” this year, during bi-weekly trips to the area.

To tag a new Great White when he joins the party, the team first finds him with a drone. A student said The side the marking process itself is quick and relatively non-invasive to the animal, similar to piercing a human’s ear. The team uses a long metal pole to insert the tag just below the animal’s dorsal fin.

Once the team tags a shark, they begin monitoring it with dozens of Bluetooth receivers placed onshore and offshore. Basically, the receiver records the passage of a tagged shark and saves the data, which the team collects periodically. Using this data, the researchers have developed some understanding of the movement patterns and habits of the sharks.

The animals live in large groups on popular beaches ranging from Del Mar to Torrey Pines State Beach. The researchers therefore found that they spent a lot of time near swimmers and surfers.

But contrary to what one might think, volume and proximity rarely lead to confrontation. Reports show that since aggregation began three years ago, only one swimmer has suffered a bite – on November 4, likely from a juvenile Great White, Tthe side reported.

Meanwhile, some sharks heavily frequent the area. The team’s data shows that some people “pinged” on underwater receivers more than 100 times.

Why do sharks remain in such large numbers? The researchers found several main reasons.

Lowe said his group thinks juveniles (less than nine or 10 feet long on average) come to the area first because its warm, shallow waters attract them and protect them from large predators. Then, he told the outlet, his team thinks the sharks end up staying there because of the many food sources in the rocky reefs.

It’s rare for so many sharks to stay in the Del Mar area for so long. So the lab is working to figure out what’s holding them back specifically. inertia contacted Lowe for comment, but he could not be reached prior to publication.

In the meantime, the Shark Lab has taken care of local initiatives to help locals better understand marine predators.

Over the summer, the lab held educational “Shark Shacks” at beaches in Southern California, including several in San Diego County. And on July 30, the team held their first “Shark @ the Beach” event since 2019. There, the team focused on bringing the details of their research to the public with the help of a presentation by Lowe.

The team is also working to study the impact of fishing on sharks. A member of the team said “targeted fishing practices” mean that sharks are more threatened by humans than humans by sharks.

Since the aggregation emerged, the outlet said, several sharks have been found dragging large hooks and long fishing lines, which can kill them.

“Within a week of discovering this aggregation, 40% [of the sharks] had signs of a peach injury,” Lowe said.

That could change next year. On January 1, 2023, a new California state law to protect sharks will go into effect. The new regulations prohibit the use of shark bait, shark lures or sharks to attract a white shark. Anglers also cannot place these items in water within one nautical mile of any shoreline, pier or pier when a white shark is “visible or known to be present”.

“This bill will help reduce fishing interactions with white sharks, helping protected sharks and ocean users by reducing the risk of snagging these sharks on public beaches and ocean jetties where people swim. , surf and dive,” Lowe said in a California department. fishing and wildlife.

If Del Mar’s well-known aggregation remains in place, it’s easy to imagine the new rules will help it thrive further.