Scientists had tagged the female shark and were following its movements after its release from the Central California facility last November. They became concerned recently when a tag attached to the shark's dorsal fin revealed movements over land.
Oscar Sosa-Nishizaki, a Mexican researcher, traced the movements to the home of a fisherman who acknowledged catching the shark in his gill-net.This was the fifth great white shark released after various periods of captivity in the aquarium's million-gallon Outer Bay exhibit. It becomes the first to have perished during the life of its tracking tags and its manner of death, according to aquarium husbandry expert Randy Hamilton, "underscores the threats that these young sharks face in the wild."
Hamilton added: "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."
The aquarium's captive white shark program has been criticized by people who claim the facility is using the iconic predators simply to lure more visitors and make more money.
The aquarium's stance has been that is is trying to increase appreciation of these mysterious creatures and raise awareness about their importance to the marine ecosystem and about the dangers they face. The program has been permitted by the California Department of Fish and Game.
Researchers with the Tagging of Pacific Predators program have used these sharks, and other white sharks tagged and released off California, to obtain insight regarding behavior and movements.
They've recently published data showing that the Northern California population of white sharks is isolated or distinct from other Indo-Pacific white sharks, in Australia and New Zealand. The same could also be of the white shark population at Guadalupe Island west of Baja California, Mexico.
Interestingly, two of the juvenile sharks released after captivity at swam to Baja California's tip within 90 days after their release. One ventured far into the Sea of Cortez.
"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," said Barbara Block, a professor of marine science at Stanford University and chief scientist with the TOPP program.
"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 the young-of-the-year pups live close to the coast i 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."
Said Sosa-Nishizaki: "It's very important to know how many of these sharks are being taken, because it has implications for international conservation efforts. "If we know how many are being caught, we will have a better idea how big a problem this is for the population."
-- Photo: A young female white shark swims in the Outer Bay exhibit soon after arriving at the Monterey Bay Aquarium. The shark was returned to the wild last November, after 69 days in captivity, but recently died after being caught in a fisherman's net off Ensenada, Mexico. Credit: Monterey Bay Aquarium/Randy Wilder
