Klamath River Fishes Poster

About the Klamath River Fish Species

The assemblage of fishes native to the Klamath River system includes widespread species, such as Chinook salmon and Green sturgeon, to species found nowhere else on Earth, such as the Klamath Smallscale Sucker and the Klamath River Lamprey.

Like the Columbia and Fraser rivers to the north, the Klamath River is one of only three rivers in the Pacific Northwest to cut through the Cascade Mountains and drain directly into the Pacific Ocean. This system has such a diverse fish assemblage due in part to its large and complex watershed and unique water features such as Upper Klamath Lake. For example, the Klamath River system has the highest diversity of lamprey species of any major watershed throughout the world.

Fish occupy a keystone position in both aquatic and terrestrial food webs. Sea-run species that are born in the clean cold river and mature in the ocean are a vital link between the freshwater and saltwater ecosystems. When fish return from the ocean to the river to spawn and die, their carcasses supply an essential source of marine nutrients into diverse terrestrial ecosystems.

Hundreds of species, from insects to bears to humans, rely on fish as a vital source of food. Through millennia, indigenous nations maintained intimate relationships with the healthy populations of the Klamath fishes. In current times obstructions, such as dams, create fish passage barriers that have severely restricted breeding habitat for some species. Agricultural run-off and water diversion change water chemistry and flow rates, which can cause major fish die-offs and adversely affect breeding success. Excessive logging causes abnormally high water temperature and levels of siltation that will reduce the available habitat of these aquatic animals. Most populations of native fishes in the Klamath River have experienced recent declines in numbers and some species are critically imperiled. Careful cooperative management of fish species in the Klamath River system is required to ensure their survival into the future.