Giant Basking Sharks Return to California Waters

Basking sharks are being spotted off the coast of Southern California in numbers not seen for decades.

These creatures, the second largest sharks in the world, are enormous; some weigh more than 10,000 pounds and reach 30 feet in length. The mouth of this shark opens up to one meter wide, while its dorsal and pectoral fins can reach two meters in length — each. That’s over six-and-a-half feet! 

A hundred years ago, basking sharks were a frequent sight in California’s oceans, but around 1960 they all but disappeared.

Thankfully, this spring they’ve returned. 

The Guardian reports:

“The sight just takes your breath away – it’s magic,” said Lotti Keenan, who saw nearly a dozen basking sharks while on a whale-watching cruise in April. Three of them circled the boat. “We knew this was such a rare thing. And people on the boat were screaming with excitement – it was like you were at a soccer game.”

Keenan was on a cruise headed for Santa Cruz Island, the largest of the Channel Islands, off the coast of Southern California. Since then, these behemoths have been spotted often near the Channel Islands, as well as further south, near Santa Monica and Long Beach.

Basking sharks are California’s biggest shark and part of the state’s natural fauna. Unlike the great white, which gets a whole lot of attention, basking sharks don’t pose a danger to humans. They have tiny teeth and long rakers which they use to filter minuscule crustaceans out of the water. 

As Heidi Dewar, a biologist with the National Oceanic and Atmospheric Administration (NOAA), explained, in a “Here And Now” interview: “Some of the largest creatures in the sea are eating some of the smallest creatures in the sea.”

In the early to mid-1900s, hundreds of these enormous fish were easily spotted along the California coast. Dewar suggests a few reasons why they abruptly vanished around the 1960s: Their valuable liver oil was used to power lamps and even to create bombs in World War II. And in case you were wondering, the basking shark’s liver is 25 percent of it total body weight. 

Another reason: at a time when fisheries had few restrictions, these giants were often caught in nets as bycatch and then thrown away. 

Dewar also explains that Canada’s department of fisheries conducted a program to eradicate basking sharks because they interfered with salmon fishing operations.

NOAA was so alarmed at the disappearance of these behemoths that in 2009, the agency included them in its “species of concern” program and called on the public to help in spotting the animals.

Dewar is excited that the basking sharks are returning, but she hesitates to name one reason for their reappearance or to conclude that the increased numbers this year mean that the shark population is increasing. 

It could be that the environmental conditions are changing to favor basking sharks, with warmer waters and more food available. In addition, in 1990 California voters banned the use of drift gill nets in state waters within three miles of the coastline. These nets were intended to catch swordfish, thresher shark and opah, but they became notorious for entangling all kinds of other creatures, such as whales and sharks. This bycatch was thrown back into the ocean, either injured or dead.

Once this measure passed, mortality rates of basking sharks went down.

It’s unclear which of these factors is responsible for the population spike, but scientists and tourists alike are thrilled at the return of the basking sharks.

Photo Credit: jidanchaomian/Flickr

64 comments

Martha P
Maria P28 days ago

Great

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Lara A
Lara Aabout a month ago

Thank you

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heather g
heather gabout a month ago

Was that ignorance on the part of Canada's dept of Fisheries?

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Peter B
Peter Babout a month ago

that's good

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Dr. Jan H
Dr. Jan Habout a month ago

thanks

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Colin Clauscen
Colin Cabout a month ago

It is good they have come back

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Lindsay Kemp
Lindsay Kabout a month ago

Good news! Amazing creatures!! I would just love to see one in the wild. We get them around the UK waters, too, sometimes. Many thanks for sharing.

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Jennifer H
Jennifer Habout a month ago

Amazing news. Thanks for sharing.

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Linda W
Linda Wabout a month ago

Wonderful news!

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Arlene C
Arlene Cabout a month ago

merci Judy

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