Zoo releases endangered turtles into wild

Posted: Thursday, July 29, 2004

PORTLAND, Ore. Endangered western pond turtles that have spent nine months being nurtured at zoos in Seattle and Portland got their first taste of the wild Wednesday when more than 125 of the reptiles were released into ponds in the Columbia River Gorge.

Only a decade ago, western pond turtles were on the verge of extinction in Washington state, when fewer than 200 were left in the wild, said Oregon Zoo conservation scientist David Shepherdson. Now there are nearly 1,000 of them living primarily in three areas in Washington state, he said.

The turtles were captured as quarter-sized hatchlings last September, before they even left the nest. Now 3 to 6 inches and weighing 70 to 100 grams (2.5 to 3.5 ounces), the turtles are less vulnerable to their worst predators, nonnative bullfrogs and largemouth bass, Shepherdson said.

''By the time we finish rearing them, they're about the size of a 3-year-old wild turtle,'' Shepherdson said. ''We know there's almost no mortality when they're headstarted like this.''

''We're going to continue doing it until we think we have enough turtles in the wild that can withstand the predation. Unless you have a number of different sustaining populations, you can't say they're safe because any one population can suffer a calamity and die out. But once we have four or five, we think they'll be safe,'' he said.

At their last day at the Oregon Zoo on Tuesday, the turtles were in oval tubs the size of small bath tubs, with a few inches of water and a sprig of silk leaves for cover.

Zookeeper Amy Cutting said the program would be necessary for the foreseeable future.

''These animals will have to be managed forever unless someone comes up with a way to eradicate the bullfrog,'' she said.

The program costs the Oregon Zoo about $12,000 a year, Shepherdson said. Starting next year, a grant from the Bonneville Power Administration would pick up most of the cost, he said.

The process of collecting the hatchlings starts in the spring, when conservationists put radio transmitters on the adult female turtles in the wild. In June, they start monitoring the turtles every two hours so they can see when the turtles leave the ponds and dig their nests. Recovery workers then put a protective cage over the nests and leave them until September, when they collect the hatchlings.



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