USGS biologists say die-offs of tiger salamanders were recorded at the same Utah location during in the early 1980s but these deaths were thought to be caused by a bacterial infection. In 1995 researchers at the University of Arizona reported on a similar die-off of tiger salamanders living in stock ponds in southern Arizona. These deaths were also attributed to an contagious iridovirus infection. Canadian scientists recently announced that they too had isolated an iridovirus from a tiger salamander die-offs near Regina, Saskatchewan, in Canada.
Salamanders are a member of the group Amphibia, a word which means "double life" and which refers to the ability of amphibians to live both on land and in water. Amphibians, which have been on Earth for some 350 million years are among the most ancient land-dwelling vertebrate animals. The international scientific community has expressed growing concern over population declines in all amphibian groups. These losses are now well documented and have occurred in a wide range of habitats, including remote and pristine areas in California, the Rocky Mountains, Costa Rica, Puerto Rico, and Australia.
On Sept. 22, the federal government's interagency Taskforce on Amphibian Declines and Deformity met for the first time. This group was formed at the initiative of Secretary of the Interior Bruce Babbitt to help investigate the causes of global amphibian declines. It will focus on science, conservation, international and education efforts.
Researchers are trying to determine why amphibians are disappearing. Current hypotheses to explain the declines include widespread infection by viruses, fungi, bacteria or parasites; increased exposure to ultraviolet radiation due t
Contact: Paul Slota
United States Geological Survey