A helping hand for endangered frogs
The Department of Fish and Wildlife is working with several partners in Washington to restore the population of native Oregon spotted frogs, which has been listed as an endangered species in this state since 1997.
Fish and Wildlife collects egg masses, and the partners raise the tadpoles to adult frogs in a safe environment before they are released.
Oregon spotted frogs are found only in Whatcom, Skagit, Thurston, Klickitat and Skamania counties. They now occupy 10 percent or less of its former range of wetlands in the Pacific Northwest.
The federal government is considering whether to protect them as a threatened species under the federal Endangered Species Act.
The Woodland Park Zoo has been part of the effort for several years, said curator Jennifer Pramuk, whose specialty is reptiles and amphibians.
"They're native to Western Washington in lowland prairie wetland habitat that is an extremely endangered habitat type in the state," Pramuk said.
"If listed, it will strengthen our ability to save them from extinction through habitat preservation," she said.
Frogs play an integral part in the wetland food web, helping to keep it in balance.
Tadpoles eat bacteria, detritus and carrion; as adults eat insects, helping to keep that population from exploding. They are predators, yes, but also prey for cranes, herons, snakes and river otters.
In addition to habitat loss, the introduced bullfrog is a problem.
"It likes to eat everything, including native pond turtles, which are endangered. We come in and try to raise frogs to a size that's harder for bullfrogs to eat," Pramuk said.
Fish and Wildlife Department biologists collect egg masses from wetlands. "We received 800 eggs this year and hope to release at least 600 tadpoles," she said.
"We have tubs with screen lids so birds can't get to them. We feed them a lot of food and there are no predators. They're pretty pampered."
The tadpoles, which hatched in mid-March, grow up in 250-gallon tubs and will be released in October. In 2012, about 2,000 frogs were set free.
"We're using floating cribs for the tadpoles. It allows them to be raised in a suspended nest in a large volume of water and be able to monitor them more closely," Pramuk said.
The tiny tadpoles grow to 2- to 2½- inches long in six or seven months before they are transplanted at Joint Base Lewis-McChord.
"It's a fairly bullfrog-free site and that's really important. It's a relatively protected site, one of the best wetland habitats remaining in the Puget Sound," Pramuk said.
Before the frogs get to settle in, "a biologist measures and weighs every single one, and surgically implants a passive integrated transponder the size of a grain of rice," she said.
"Later they can monitor to find adults, then scan the transponder with a reader. We can find out which frog it is, which institution raised it and could even link it with a specific pond," Pramuk said.
Oregon spotted frogs are the most aquatic frog in the state. Their eyes have evolved to a more dorsal position suitable to spending most of its life in water.
"They remain mostly submerged. Their eyes are a little different … they look more like goggles and are positioned a little better to see above the water line," Pramuk said.
No one really knows how many are left.
"They're hard to find as adults so we have to count egg masses. In most frog species, 90 percent or higher do not make it to adulthood," she said.
Pramuk, formerly with the Bronx Zoo, has been a curator at Woodland Park for 3½ years. Pramuk became a frog fan very early.
"As a young kid (in Ohio) I had an opportunity to be more involved with nature. I was about 2 when I was playing with amphibians. That's what got me hooked, and I didn't outgrow it."
"By the time I was 6, that was it. I just didn't know that it was called a herpetologist," Pramuk said.
Columnist Sharon Wootton can be reached at 360-468-3964 or www.songandword.com.
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