Endangered Klamath suckers

Since Lost River suckers (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) hatched in the early 1990s, almost none of the fish have survived to adulthood. When full grown, Lost River suckers are the largest of the Klamath suckers, averaging about two and a half feet long, whereas shortnose suckers are at around twenty-one inches. Rather than an inability to spawn, these species are limited by very high mortality within the first year or two of life. There are many hypothesized causes of high juvenile sucker mortality, including poor water quality, diseases aggravated by warming water temperatures, and the reduction in wetland habitat that provides food and cover.

The number of adult endangered Lost River and shortnose suckers in Upper Klamath Lake, the primary remaining habitat for these species, declined by 65 to 85 percent between 2001 and 2020. Extinction is increasingly likely for these species unless their population trajectories can be changed. The Klamath Tribes, the U.S. government, the State of Oregon, and several nonprofits are working together to prevent sucker extinction in the Klamath Basin.