PORTLAND, Ore. (KOIN) – Nearly two dozen northwestern pond turtles can “just keep swimming” in the wild after the Oregon Zoo, wildlife officials and volunteers released them from captivity and into the waters of the Columbia River Gorge last week. 

Northwestern pond turtles are considered endangered and the Oregon Zoo is working to help restore their populations. 

On Thursday they released 23 turtles that had been reared at the zoo. 

The turtles were collected from wild sites shortly after they were born in October and since then, they’ve been enjoying the warmth and light of a simulated summer at the zoo’s conservation lab. The zoo waited to release them until the turtles grew big enough to have a fighting chance in the wild. 

This “head-start” program is part of the Western Pond Turtle Recovery Project. Conservation scientists will collect newly hatched turtles gathered from wild sites and nurture them at the zoo for up to a year. 

“In the conservation lab, the turtles experience summer year-round,” said senior keeper Sara Morgan. “In about nine months they grow to the size of a young adult wild turtle. This gives them a much greater chance of surviving in the wild.” 

The turtles get a taste of life in the wild by spending time outside to adjust to changing temperatures. Once the turtles weigh about 50 grams, conservationists take them to ponds along the Columbia River Gorge where they’re returned to their natural habitat and monitored for safety. 

In one study, scientists estimated that 95% of the turtles released back into the Gorge survive annually. 

Morgan said giving turtles time to grow to a larger size protects them from predators like bullfrogs. The bullfrog is considered invasive in the Pacific Northwest. It’s been driving pond turtles and other small, vulnerable aquatic species to the brink of extinction, the Oregon Zoo said. 

The northwestern pond turtle is listed as an endangered species in Washington and a sensitive species in Oregon. About two decades ago, the turtles almost died out completely in Washington. There were fewer than 100 of them left in the state. 

Since then, the zoo has released more than 1,500 turtles into the wild.