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UPDATE - 29 OCTOBER 2001
Anchorage (Alaska) Daily News, 29 October 2001
A study revealing wide-spread abnormalities in frogs in Maine, Vermont and Minnesota has alarmed scientists since amphibians are barometers of potentially serious environmental problems.
In the second year of a national survey looking for abnormal amphibians across the United States, federal biologists found 33 wood frogs with deformities last summer among sample populations in three Alaska wildlife refuges from the Kenai Peninsula to Interior Alaska. Unlike some Lower 48 refuges that have reported animals with extra legs or missing eyes, most of these troubled frogs lacked limbs or toes. But one frog scooped from a pond in the Arctic National Wildlife Refuge near the Porcupine River suffered from an unusual growth: Its ankle was connected to its pelvis by a thread of tissue. "I don't think it could fully extend its leg," said Jordan Stout, a contaminants specialist with the U.S. Fish and Wildlife Service in Anchorage.
Whether these discoveries signal environmental trouble for Alaska's most common amphibian or are largely natural occurrences -- some caused by pond predators nibbling on tadpoles -- won't be known until the frogs are tested and more field work is done, said Kim Trust, a contaminants specialist coordinating the program for the U.S. Fish and Wildlife Service. "It's still too soon to tell," she said. "We're at the baby stage of looking. . . . It could be anything, it could be nothing." Finding 33 abnormal frogs among 799 -- a rate of about 4.5 percent -- is slightly above what biologists would expect among a normal wild population. "We're right around the threshold," Trust said. "It makes you think about it."
Recent results underscore the need for caution. In 2000, Trust and other people caught 348 frogs near ponds in the Swanson River area of the Kenai National Wildlife Refuge and found 24 frogs with deformities, including one with missing eyes. But the National Wildlife Health Center in Madison, Wis., examined them over winter and reported that half had been bitten or injured as they grew. What factors in the environment triggered the other 12 frogs to develop malformations isn't known yet, Trust said. This summer, researchers began collecting aquatic insects and sampling the ponds for contaminants. "We're just starting to look (for causes) this year," she said.
Sensitive to environmental changes and especially vulnerable to pollution, amphibians like frogs, toads and salamanders have been declining worldwide for years, possibly serving as a warning about the spread of contaminants, disease and other problems. National attention intensified when a group of Minnesota middle school students found large numbers of frogs with extra, misshapen or missing limbs in 1995. Since then, the North American Reporting Center for Amphibian Malformations has documented an increasing number of abnormal creatures across the United States. In 2000, the wildlife agency launched a survey of 43 refuges in 31 states and provided $20,000 for the work on the Kenai. This year, the Alaska funding was increased to $80,000 and allowed researchers to sample near the Porcupine and Koyukuk rivers and return to ponds on the Kenai. "The initial purpose of this survey was to look at our national wildlife refuges and see if we have a problem with frogs," Trust said. "We're going to continue this project."
Collecting frogs in Alaska for science isn't the same carefree chore one might recall from childhood, wading at the neighborhood pond. For one thing, the thumbnail-sized wood frogs complete their metamorphosis from tadpoles fast, then bolt from their natal waters to forage for bugs in the surrounding brush. "A whole cohort of froglets can leave the pond in a day," Trust said. "If you're not right there when they metamorphose, you've missed them for the year." That meant that Trust drew on about 30 biologists and technicians to monitor the ponds and be ready to converge when the animals were about to invade dry land. On the Kenai, they visited 16 Kenai ponds once a week from spring to midsummer, then staked them out for a week in July. They caught 397 frogs around eight ponds and found 20 with abnormalities. "It's fairly labor intensive," she said.
The biologists also visited 13 ponds in ANWR south of the Brooks Range and three ponds in the Koyukuk National Wildlife Refuge. About 50 frogs caught around a single Koyukuk pond produced five abnormalities. They collected 352 frogs from six ANWR ponds and found eight of them to be abnormal. In ANWR, along the Porcupine about 100 miles northeast of Fort Yukon, the team found many frogs dispersing when they arrived in July. "I think we were probably a couple days late, actually," Stout said. "We sort of scrambled around for the first four or five days, trying to catch the frogs at the point where they were popping out of the ponds." Depending on the pond and the visibility, they tried different methods, Stout said. The pelican technique involved scooping blindly through the plants and then sorting through the net for frogs. The stork technique was more fun: They would stalk along the shore and then pounce on any furtive movement in the shallows. The bugs were always persistent, but the humans could not use insect repellent on hands because it might harm the frogs or tadpoles, Stout said. Finally, they resorted to latex gloves. "That was our revenge, watching them try to bite through the latex," Stout said.