Klamath Falls Field Station
Lost River sucker (Deltistes luxatus)
Lost River suckers are long-lived catostomids endemic to the Upper Klamath River Basin in Oregon and California. Individuals have been aged to over 40 years and the largest adult females can grow to 800 mm fork length. Lost River suckers were listed as endangered under the U.S. endangered Species Act in 1988 because of range contractions, declines in abundance, and a lack of evidence of recent recruitment to adult populations. Numerous threats common to imperiled fishes in the western United States also affect the recovery of Lost River suckers (e.g., habitat alteration and degradation, nonnative species). Two distinct spawning subpopulations of Lost River suckers coexist in Upper Klamath Lake. One subpopulation exhibits a reproductive strategy similar to other western lakesuckers (genus Chasmistes) and migrates relatively short distances up tributaries to spawn in the spring. Although spawning may have occurred in other tributaries in the past, nearly all riverine spawning activity for the suckers is now restricted to the lower Williamson River and the Sprague River. The other subpopulation spawns at upwelling springs along the eastern shore of the lake below Modoc Rim. The majority of spawning activity for both subpopulations occurs in March and April.