Saturday, June 25, 2005

Captivity, a death sentence for a great white shark

When fishermen off the Southern California coast accidentally caught a juvenile great white shark in their nets eight days ago, it looked like the Monterey Bay Aquarium was getting lucky again.
She was a female, apparently healthy, about 5 feet long and weighing about 60 pounds.


Last August, Southern California fishermen accidentally caught a juvenile great white shark in their nets. She was a female, apparently healthy, about 5 feet long and weighing about 60 pounds.
That time, everything went right, and the great white became the greatest attraction ever at the aquarium, spending a world-record 198 days in captivity before being set free in March because she had grown too large and too aggressive.

This time, however, pretty much everything went wrong, and in less than a week, the new shark was dead.

Aquarium officials said it was a case of not having exactly the right equipment on hand.
"In ideal circumstances we would have put her straight into the ocean pen," said aquarium spokesman Ken Peterson. But the ocean pen wasn't available quite yet. It was being towed up from storage in Mexico and was not due to arrive in Malibu until last Wednesday -- the day the aquarium would begin the fourth season of its long-term great white shark research program.

In the meantime, a holding pool at the Southern California Marine Institute in San Pedro was available. A few years ago, a young great white had spent three and a half days in it before being tagged and released back into the wild.

Aquarium officials thought it might work. After all, the new shark would only have to spend two days there.

So aquarium officials decided to try to keep the new shark.

"It seemed like a reasonable thing to do," Peterson said Tuesday. "... Our husbandry staff had some comfort level." But then, "Something in transit took longer than it should have."

The officials kept thinking, "The pen will be here any day," which turned out to be Friday. That meant the shark had spent about four days in the holding pool -- twice as long as originally expected, but only half a day longer than the earlier shark's stay.

During those four days, "She was swimming really well in the tank and looked really good," according to an employee of the Marine Institute who declined to be identified. "... As good as sharks do in those conditions."

She did not eat, however.

That was worrisome to the aquarium team, but the shark that had stayed in the pool before hadn't eaten either. Besides, at some point the new shark had injured an eye, Peterson said.

"We didn't feel comfortable releasing it into the wild."

So Friday afternoon, as soon as the ocean pen was set up, the team moved the shark, using the same methods they'd used when moving the great white they'd kept before.

The institute employee disagreed that the shark was injured while she was there and speculated that something must have happened while she was being moved.

"It's always a real crapshoot trying to get a white from a holding pen into the ocean pen," he said.
In any case, the move apparently went fine in every other respect.

On Saturday the aquarium team tried to check up on the shark by making a "surface observation," but they never saw her. "Visibility varies day to day," Peterson said.

So Sunday morning they sent in some divers, who found her dead. A necropsy was performed Monday, but results aren't back yet.

It's obvious why aquarium officials would have preferred to keep the great white in the ocean pen from the beginning. Being in it is just about like being free except that netting keeps the shark in one place. One big place. The pen contains four million gallons, and the shark has plenty of room to swim around.

By contrast, the holding pool contains only about 19,000 gallons, and since it's only eight feet deep and 20 feet in diameter, the shark has plenty of chances to bump into walls.

Still, even after her move to the more spacious ocean pen, the shark didn't start eating. The food put in for her was found uneaten Sunday.

If all had gone well, the new shark might have come to live at the aquarium for a while, or she might have simply been tagged and released. Aquarium officials hadn't decided. "We evaluate case by case... to see if it's a candidate to bring back here," Peterson said.

But it's not uncommon for things not to go well when a great white is caught, said Chris Lowe, director of the CSU-Long Beach SharkLab, which collaborates with the aquarium in its shark research program.

"It depends on how long it's been on the line or in the net," he said, "and how stressed it got.... In this case, if they could have got it into the sea pen faster, that might have helped."

Sean Van Sommeran, executive director of the Pelagic Shark Research Foundation in Santa Cruz, is a critic of the aquarium's research. He maintains that in his own program, he's able to tag sharks without catching or injuring them.

"These animals can't be kept long-term," he said, "and short-term captivity compromises them."
But Lowe believes that the aquarium's research is invaluable.

"We're just scratching the surface in terms of what we understand about these animals," he said. "... And we've learned more in the last four years than we did in the previous 50."

And the aquarium continues to believe that its program -- including keeping a great white in captivity -- is a benefit to great whites in general. "There's a million people who have seen a white shark who's living," Peterson said, referring to the shark who drew huge crowds to the aquarium from last September to last March. "... That's a million people who can help make the case for shark conservation."

1 Comments:

Blogger Wednes Fri said...

How sad...

11:59 PM  

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