Great White Shark Released from Monterey Aquarium Dies in Fishing Net Off Baja California
Filed under: Census of Marine Life,Discovery,News & Resources
The young great white shark released by the Monterey Bay Aquarium in November has been found dead in a fishing net off Baja California.
(From Contra Costa Times / MONTEREY) — She is the only one of the five white sharks exhibited at the aquarium known to have died after being released, according to the aquarium staff.
The shark was fitted with two electronic tracking tags when she was released in Monterey Bay, one of which was recovered by Mexican researchers collaborating with the aquarium to study migrations of young great white sharks.
The shark was on exhibit for 69 days before being released. She traveled about 500 miles south before being caught in early March, in a gillnet set by a fisherman in waters off Ensenada, Mexico.
“This just underscores the threats that these young sharks face in the wild,” said Randy Hamilton, vice president of husbandry for the aquarium. “Though they’re legally protected in both California and Mexico, they are still caught accidentally by commercial fishermen on both sides of the border. Not all of them survive.”
Scientists on both sides of the border expressed concern over sharks caught in fishing nets.
“It’s very important to know how many of these sharks are being taken, because it has implications for international conservation efforts,” said Oscar Sosa-Nishizaki, a fisheries researcher with the Center for Scientific Investigation and Higher Education in Ensenada. “If we know how many are being caught, we will have a better idea how big a problem this is for the population.”
Sosa-Nishizaki and his colleagues collaborate with aquarium researchers to tag and track young white sharks in the Gulf of California and on the Pacific coast of the Baja Peninsula, and to collect DNA from the sharks.
Researchers with the Tagging of Pacific Predators – www.topp.org – say their data shows the northern California great white shark population is isolated from the world’s other white sharks; other studies suggest the same is true for the population off Mexico.
Barbara Block, a professor of marine sciences at Stanford University and chief scientist of the TOPP program, said “Our tagging programs on adults and juveniles along the California coast show that we have several white shark neighborhoods in central California and northern Mexico. Adults from both regions spend half the year foraging around coastal pinniped colonies and the other half far from shore. The juvenile tagging program has helped us to better understand that young-of-the-year pups live close to the coast in warmer habitats, where they’re vulnerable to local fishing gear. By learning where they go, we can help ensure their future by establishing programs to monitor these unique populations.”
TOPP is one of 17 projects of the Census of Marine Life, a 10-year, 80-nation endeavor to assess and explain the diversity and abundance of life in the oceans. TOPP researchers are tracking top predators that roam the Pacific Ocean – including great white sharks.
The Monterey Bay Aquarium is the only institution to keep a great white shark on exhibit for more than 16 days.
Tracking data from four previous great white sharks kept at the aquarium shows that the first two sharks traveled to the southern tip of Baja California and beyond within 90 days, and a third with a 30-day tracking tag headed to waters near Santa Barbara. A fourth shark, tagged and released near Santa Barbara after 11 days in Monterey, was caught and released in good health just a few days later by a commercial fisherman in Santa Barbara.
The aquarium has no plans to bring in another great white until summer 2011 at the earliest because of planned renovations to the million-gallon Outer Bay exhibit.
