U.S. Fish & Wildlife Service Contaminants as Contributing Factors to Wood Frog Abnormalities on the Kenai National Wildlife Refuge, Alaska

Deformed amphibians have been observed in the Kenai National Wildlife Refuge, Alaska. Environmental variables such as contaminants, ultraviolet radiation [UV], or parasites may cause deformities. It is important to identify the environmental cause of deformities in order that effective management strategies can be implemented to enable the recovery of affected populations. To determine whether waterborne chemicals are responsible for deformities reported in wood frogs (Rana sylvatica) in wetlands (Oil Fields 1 and 3) in the Swanson River Oil Field in the Kenai National Wildlife Refuge, we deployed semipermeable membrane devices (SPMDs) to accumulate lipophilic contaminants. We then exposed tadpoles (spring peepers, Pseudacris crucifer) to the SPMD extracts at two levels of UV-B radiation. Frogs exposed to SPMD extracts from Oil Field 3 were smaller upon metamorphosis and took longer to reach metamorphosis than frogs reared in other treatments. We found no effect attributable to UV-B or the interaction between UV-B and SPMD extract. We noted no deformities throughout the