1. Department of Microbiology, Center for Fish Disease Research, 220 Nash Hall, Oregon State University, Corvallis, Oregon 97331, Gulf Ecology Division, U.S. Environmental Protection Agency, Gulf Breeze, Florida, Western Ecology Division, U.S. Environmental Protection Agency, Corvallis, Oregon, Oregon Cooperative Fish and Wildlife Research Unit, U.S. Geological Survey, Corvallis, Oregon, and Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon