Juvenile Sucker in Upper Klamath Lake, OR

Previously published research indicated that predation by piscivorous colonial waterbirds in the Upper Klamath Basin was a source of mortality for Lost River suckers (Deltistes luxatus) and Shortnose suckers (Chasmistes brevirostris), including mortality of Sucker Assisted Rearing Program (SARP) fish. Avian predation on recently released Chinook Salmon (Oncorhynchus tshawytscha) in the...

Executive Summary The work reported in this publication provides updated data and interpretation for sampling years 2015 and 2022 of the juvenile monitoring project. The study objectives, background, study area, species description, and methods remained the same or similar throughout the years, while the executive summary, results, and discussion were updated each year. Therefore much of...

Objective High juvenile mortality prevents recruitment into the adult populations of endangered Shortnose Sucker Chasmistes brevirostris and Lost River Sucker Deltistes luxatus in Upper Klamath Lake, Oregon. To address the lack of recruitment, the U.S. Fish and Wildlife Service implemented the Sucker Assisted Rearing Program (SARP). Managers developing the rearing program lack...

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...

Executive Summary Populations of federally endangered Lost River (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) in Upper Klamath Lake, Oregon, and Clear Lake Reservoir (hereinafter, Clear Lake), California, are experiencing long-term decreases in abundance. Upper Klamath Lake populations are decreasing not only because of adult mortality, which is relatively low, but...

In the western United States, water allocation decisions often incorporate the needs of endangered fish. In the Klamath River basin, an understanding of temporal variation in annual survival rates of Shortnose Suckers Chasmistes brevirostris and Lost River Suckers Deltistes luxatus and their relation to environmental drivers is critical to water management and sucker recovery. Extinction...