Lost River Sucker (Deltistes luxatus) - KFFS

Science Center Objects

Species Studied

Lost River Sucker (Deltistes luxatus)

Adult Lost River sucker

Adult Lost River sucker. Credit: USGS, Western Fisheries Research Center (Public domain.)

Lost River suckers (Deltistes luxatus) are long-lived catostomids endemic to the Upper Klamath River Basin in Oregon and the Lost River Basin in 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, OR. 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.  Another smaller population of Lost River Suckers exists in Clear Lake Reservoir, CA.  This population migrates a short distance up Willow Creek to spawn in early spring.

The USGS runs a long-term monitoring program for this species that tracks abundance, survival and recruitment to spawning aggregations. Passive integrated transponder (PIT) technology allows staff to track adult suckers through multiple years. These data are used in populations models to estimate demographic parameters.  PIT tag data are also used to understand the timing of spawning migrations into rivers and to shoreline springs. The Klamath Falls Field Station staff uses PIT technology to investigate how lake management effects spawning behavior and survival of adult suckers.  Survival of juvenile suckers is monitored in a long-term monitoring program and in-lake mesocosoms. Mesocosms allow fish to experience ambient conditions and to be closely observed for development of disease.  Sucker research is used to help guide water management in the Upper Klamath Basin and to help plan sucker recovery actions.    


Adult Lost River sucker

Adult Lost River sucker. Credit: Tupper Blake, U.S. Fish and Wildlife Service. (Public domain.)

Spawning Lost River suckers

Spawning Lost River suckers. Credit: USGS, Western Fisheries Research Center. (Public domain.)