Increasing Number Of Leopard Sharks Off La Jolla Attracts Snorkelers, Scientists
Every year, from June to December, thousands of leopard sharks gather at the southern end of La Jolla Shores. It is the largest annual gathering of the sharks along the open coast of California. This summer, it is even larger than the previous two years.
“It’s a really rare occurrence to see so many of these leopard sharks to come into an area like this,” said Birch Aquarium shark naturalist Elliott Beltran.
Beltran and other Birch Aquarium naturalists lead snorkel trips to see the spotted leopard sharks. The trips have been so popular that they have added new dates through the end of September to accommodate high demand.
Del Mar resident Kate Zimmer brought her two children to a recent Saturday morning snorkel trip.
“We’re lucky. Most people don’t get to do this,” Zimmer said. “I hope what they take away is that they can protect this, or they’re stewards of this, instead of it’s something to be afraid of.”
The snorkel trip began with an educational talk about sharks and other sealife found off the San Diego coast. Beltran warned about stingrays and taught the snorkelers to shuffle their feet so the rays are scared off. The leopard sharks, however, are harmless to humans.
“They have these small mouths, these really small mouths, and you’re in no danger unless you’re a squid or a small crab,” Beltran said.
For years, it was a mystery why the leopard sharks chose this particular spot to congregate. Thanks to research completed in 2013 by Andy Nosal at the Scripps Institution of Oceanography, we now know that 97 percent of the sharks are pregnant females. Beltran explained that the sharks are drawn to the spot in front of the Marine Room restaurant because of warm, calm waters that help their young develop faster.
Temperature is key to attracting the pregnant leopard sharks, so that also explains why there are more this year than the last two summers.
“Two years ago, we had an El Niño and that increased the temperature of the water all over the coastline, and it didn’t make La Jolla as unique as it has been in the past,” Beltran said. “But now that temperatures are going back to normal along our coastline, La Jolla Shores is becoming warmer again compared to the other coastlines.”
After spending the night eating squid in nearby offshore La Jolla Canyon, the sharks start gathering near the Marine Room at sunrise.
They are not the only large sealife in the area. Kate Zimmer’s son, Will, saw stingrays and a guitarfish.
“Then I saw three sharks. One of them was as tall as me,” said Will Zimmer, who is about five feet tall.
Kate Zimmer’s daughter, Lindsey, also saw a few leopard sharks. She said she now wants to be a shark researcher when she grows up.
“It was more exciting than scary, I was surprised,” Lindsey Zimmer said.
“If you’re raising your kid here, you want them to see what’s here, not take them somewhere else,” Kate Zimmer said. “I want them to experience what we have as a natural amenity.”
Anyone interested can sign up for the snorkeling trips on the Birch Aquarium website through September, when the sharks’ numbers start to dwindle. Although many of the dates are sold out, more dates are being added to the website soon.