VIA – PRESSTELEGRAM
Great white haven
SHARKS: Cal State professor’s research shows their numbers are recovering off the coast.
By Kelly Puente, Staff Writer
Posted: 07/28/2011 06:03:30 PM PDT
Updated: 07/29/2011 09:38:45 AM PDT
LONG BEACH – Swimmers and surfers could have some surprising company in the deep waters off the Southern California coast this summer.
Christopher Lowe, a marine biology professor at Cal State Long Beach, says new research shows that great white sharks are growing in numbers off the coast of California thanks in part to fishing regulations that were established in the mid ’90s.
“It’s a good sign because it means that the conservation and strategies put in place are working,” he said.
Lowe, the director of Cal State Long Beach’s Shark Lab, has been collaborating with the Monterey Bay Aquarium for eight years in a study of juvenile great whites.
His research will be featured in the Discovery Channel’s Shark Week premiere program, “Great White Invasion,” at 9 p.m. Sunday. The episode follows Lowe, a Long Beach resident, and a team of his students as they seek to learn more about great white populations and migratory patterns.
Southern California has long been a seasonal nursery for baby great whites, which prey on fish, rays and other sharks. Lowe believes their numbers are growing based on reported sightings and catches at fisheries. A 1994 ban on gill nets along the shoreline has helped the juvenile population recover, he said.
“It typically takes a population at least 10 years to start to recover, so we believe we’re now starting to see the effects of the gill-netting regulation and other conservation efforts,” he said.
The largest predatory fish on Earth, great whites are found in cool, coastal waters throughout the world. They grow to an average of 15 feet in length, although specimens more than 20 feet long have been recorded.
Despite its notoriety as a feared predator, many mysteries still surround the habits of this massive fish.
Great whites were previously thought to be coastal sharks, but Lowe said research through new electronic tagging shows that adults off the California coast actually migrate thousands of miles into open ocean each year.
“We still don’t know what they’re doing out there,” he said, adding that one theory is the sharks are feeding on giant squid.
As part of his research, Lowe has tagged nearly 20 babies, called pups, between Santa Barbara and Dana Point in the past eight years. Last summer Lowe and his graduate students began using acoustic tags to track pups. Implanted under the shark’s rough skin, the tags record migratory patterns and then transmit the information to acoustic listening stations located off piers from Morro Bay to San Clemente.
“Last summer we tagged four baby white sharks off Malibu, and we detected all four of them up into the fall and early winter months,” he said. “Then they all went down to Baja, which is a common pattern that we’ve seen from most of the sharks that we’ve tagged over the last eight years.”
Lowe said the pups are expected to return this summer to Southern California, where their movements will be tracked by the listening stations.
While the growing population is promising, Lowe said tissue samples from pups caught off the coast are showing a disturbing trend.
“We’ve actually found amazingly high levels of contaminants (DDT, PCBs and mercury) in many of these pups who may only be a couple of months old,” he said. “We’ve measured some of the highest mercury loads in the muscles of these baby sharks that have ever been measured in any shark anywhere in the world.”
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