OLYMPIA – In an ongoing effort to recover native Puget Sound wetland species, some 500 endangered Oregon spotted frogs were released into the wild after spending the first nine months of their lives in a captive-rearing program.
Biologists from the Washington Department of Fish and Wildlife (WDFW), Woodland Park Zoo, Oregon Zoo, and the U.S. Army released the frogs this fall into Dailman Lake on the Fort Lewis Military Reservation in Pierce County in a collaborative effort to return the endangered frog to a portion of its historic habitat.
The frogs, most weighing less than two ounces, were collected as fertilized eggs last spring, and “head-started” in captivity at the zoos and the Cedar Creek Corrections Center near Olympia to improve their chance of survival once they return to the wild.
The frog release is the second in a five-year collaborative effort led by WDFW to establish a self-sustaining population on the Fort Lewis site. Approximately 600 frogs reared at Northwest Trek Wildlife Park and Oregon Zoo were released at the same location last year, 28 of which received radio transmitters for tracking.
This year, two Cedar Creek inmates raised a number of the young frogs through the Sustainable Prisons Project, a partnership between The Evergreen State College and the Washington State Department of Corrections that allows incarcerated men and women to participate in science-based conservation projects.
The Dailman Lake area was chosen for the reintroduction because it contains diverse wetlands that can sustain a frog population, said Jim Lynch, Fort Lewis wildlife biologist.
All of the frogs tracked last year during a radio-telemetry study appear to have survived predators.
“We were encouraged with these findings, but direct observation was limited because the frogs are very effective at concealing themselves,” Lynch said.
This year, to improve data collection, about a quarter of the released frogs will be equipped with a tiny microchip that can be scanned by a wand reader.
In 2010, biologists will begin looking for egg masses to determine if the frogs have established breeding populations.
The Oregon spotted frog historically ranged from southwestern British Columbia to northeastern California, but is now known only in Klicikitat and Thurston counties in Washington. Loss of habitat, predation by non-native species such as the American bullfrog, and disease have decimated its numbers, which prompted its listing as a Washington state endangered species in 1997.
“Frogs worldwide are known as sentinel species that play an important role in ecosystems,” said Marc Hayes, senior research scientist and project lead for WDFW. “When they disappear from their habitat, these ecosystems can be disrupted.”
The U.S. Department of the Interior recently awarded WDFW a grant to coordinate range-wide recovery projects for the Oregon spotted frog and associated species. A portion of the grant supports the Fort Lewis project.
“Restoring native wetland species such as the Oregon spotted frog and protecting habitat over broad areas are examples of an ecosystem approach that WDFW and its partners are taking to help restore the state’s biodiversity,” said Phil Anderson, WDFW director.
Partners involved in the reintroduction program at Fort Lewis include WDFW, Fort Lewis Military Reservation, Woodland Park Zoo, Oregon Zoo, Point Defiance Zoo & Aquarium, Northwest Trek Wildlife Park, Washington State Department of Transportation, U.S. Fish and Wildlife Service, The Evergreen State College, Washington State Department of Corrections, Port Blakely Tree Farms, Washington Department of Natural Resources, NW Zoo & Aquarium Alliance, U.S Geological Survey, Mountain View Conservation & Breeding Centre and The Nature Conservancy.