Captive great white shark returned to the ocean

A great white shark that survived far longer than any other in captivity was returned to the wild on Thursday because it was growing too large and had begun preying on other fish at the Monterey Bay Aquarium.

The shark, captured by a halibut fisherman off the coast of Orange County in August, was in captivity for 198 days. The previous captivity record was 16 days.

It was also the first great white to regularly eat outside the wild, putting on almost 40kg while at the aquarium.

"The larger she grew, the more that human safety and animal welfare concerns became a factor in our thinking," said Randy Hamilton, vice president of husbandry for the aquarium. "It's more risky to handle a larger animal."

The predator had killed two soupfin sharks earlier this year, although aquarium officials weren't sure whether the shark was hunting at the time. After close observation this week, researchers noticed it was starting to exhibit true hunting behavior.

"We've been watching to see if she was actively hunting other animals in the exhibit," Hamilton said. "When we saw clear signs on Monday, we decided an immediate release would be best."

Aquarium staff released the shark south of Monterey Bay. Its movement will be tracked for 30 days with an electronic tag that was attached before its release.

During its stay in Monterey, the shark had grown from a length of 1.52m and a weight of 28.12kg to more than 1.83m and 73.48kg. It was about a year old when it was caught.

The aquarium acquired a wealth of information on how best to care for the animals in captivity.

Mark Berman, assistant director of the International Marine Mammal Project at the Earth Island Institute, applauded the release. The San Francisco group is leading efforts against keeping dolphins, orcas and other advanced sea life in captivity.

"In the future, we think the Monterey Bay Aquarium and others should work on protecting these species in the wild," he said. "I'm sure they now have valuable footage and data they can utilise without having to bring another (shark) in."

The aquarium, however, said it will try to find another young great white shark for the exhibit later this year. It also is expanding other research that involves tagging and tracking the animals.

The aquarium, which opened in 1984 at the site of an abandoned fish cannery, saw attendance jump 30 percent after the shark arrived.