In 1988 the U.S. Fish and Wildlife Service listed two endemic fishes of the upper Klamath River basin of Oregon and California, the sucker and the Lost River sucker, as endangered under the federal Endangered Species Act (ESA). In 1997, the National Marine Fisheries Service added the Southern Oregon Northern coastal California (SONCC) coho salmon as a threatened species to the list. The leading factors attributed to the decline of these species were overfishing, blockage of migration, entrainment by water management structures, habitat degradation, nonnative species, and poor water quality. Endangered and Threatened Fishes of the Klamath River Basin addresses the scientific aspects related to the continued survival of coho salmon and shortnose and Lost River suckers in the Klamath River. The book further examines and identifies gaps in the knowledge and scientific information needed for recovery of the listed species, and provides an assessment of scientific considerations relevant to strategies for promoting the recovery of those species.