Wildlife Experts Ponder Cause of ‘Eco-Catastrophe’
FALLON, Nev. (AP) _ An estimated 3 million fish and 1,500 migratory birds have been found dead at a federal wildlife refuge, and scientists said pollution may be at least partly to blame.
″We’ve never seen both dead fish and birds in the same area and never of this magnitude,″ said Kenneth Merritt of the state Department of Wildlife.
Preliminary examinations of four birds from the Stillwater National Wildlife Management Area showed they died of avian cholera, but two others showed no signs of the disease and scientists Friday were unable to say what killed them.
The U.S. Geological Survey in Denver is testing water samples from the refuge for arsenic, heavy metals, selenium and other hazardous compounds or low oxygen content caused by algae.
″It definitely appears there is more than one problem going on,″ said Kathryn Converse, disease control specialist with the National Wildlife Health Center in Madison, Wis., where the animals were examined.
The deaths began shortly before Christmas and cut across species of birds with different eating habits, including ducks, cormorants, geese, egrets, blue herons, coots, ravens, California gulls and white pelicans, officials said.
The only fish killed was the tui chub, an 8- to 10-inch scavenger. Dead chub lined the 30-mile shoreline of the Carson Sink, a vast body of water that is a natural terminus for the Carson and Humboldt rivers in west-central Nevada.
″It looked like whatever killed them was fairly fast,″ said Steven Thompson, a biologist with the U.S. Fish and Wildlife Service.
Terry Young, a scientist with the San Francisco-based Environmental Defense Fund, calling the phenomenon an ″eco-catastrophe.″
Stillwater is home to the endangered bald eagle, the golden eagle and tens of thousands of migratory birds, some on the sensitive species list. So far, no eagles have been found dead, officials said.
High levels of selenium, which has been traced to agricultural runoff, have been recorded at or near 21 national refuges, including Stillwater.
Bird deaths and deformities at Kesterson National Wildlife Refuge near Los Banos, Calif., have been traced to selenium.