Distribution and Status of Seven Native Salmonids in the Interior Columbia River Basin and Portions of the Klamath River and Great Basins

Abstract

Abstract We summarized presence, absence, current status, and potential historical distribution of seven native salmonid taxa—bull trout Salvelinus confluentus, Yellowstone cutthroat trout Oncorhynchus clarki bouvieri, westslope cutthroat trout O. c. lewisi, redband trout and steelhead O. mykiss gairdneri, stream type (age-1 migrant) chinook salmon O. tshawytscha, and ocean type (age-0 migrant) chi nook salmon—in the interior Columbia River basin and portions of the Klamath River and Great basins. Potential historical range was defined as the likely distribution in the study area prior to European settlement. Data were compiled from existing sources and surveys completed by more than 150 biologists. Within the potential range of potamodromous salmonids, status was unknown in 38–69% of the area, and the distribution of anadromous salmonids was unknown in 12–15%. We developed models to quantitatively explore relationships among fish status and distribution, the biophysical environment, and land management, ...