Deltistes luxatus

Lost River sucker

Family: Catostomidae · Class: Actinopterygii · Order: Cypriniformes

Conservation status: FP · Endangered · G1 S1

The Lost River sucker is a large freshwater fish endemic to the upper Klamath River basin. Adults typically measure 300 to 610 mm (12 to 24 inches) in total length and can weigh up to 4.5 kg (10 pounds), making it one of the largest members of the sucker family. The body is robust and elongated with a large, terminal mouth equipped with thick, fleshy lips adapted for bottom feeding. Coloration varies from dark olive-green to brownish-black dorsally, fading to lighter tones on the sides and belly. The species exhibits sexual dimorphism during spawning season, with males developing pronounced tubercles on the head and fins. Historically, Lost River suckers inhabited Clear Lake and Tule Lake in northern California and southern Oregon, along with connecting waterways including the Lost River system. The species' range has contracted dramatically since the early 1900s. Current populations in California are restricted to Clear Lake in Modoc County, while Oregon populations persist in Upper Klamath Lake and associated tributaries. The species has been extirpated from Tule Lake and much of the Lost River system due to habitat modifications. Lost River suckers occupy large, deep lakes and associated tributaries within the upper Klamath basin. Adults prefer open water habitats in lakes with depths exceeding 3 meters (10 feet), typically in areas with rocky or sandy substrates. Water temperatures in occupied habitats range from 4 to 28 degrees Celsius (39 to 82 degrees Fahrenheit), though the species shows preference for cooler temperatures. Spawning occurs in tributary streams and lake margins with gravel substrates and flowing water. This species exhibits a complex life cycle with distinct habitat requirements for different life stages. Spawning occurs from March through May when water temperatures reach 10 to 16 degrees Celsius (50 to 61 degrees Fahrenheit). Females broadcast up to 46,000 eggs over gravel beds, with no parental care provided. Larvae drift downstream to lake environments where they mature over several years. Adults are primarily benthivorous, feeding on aquatic invertebrates, algae, and detritus. The species is long-lived, with individuals reaching ages exceeding 40 years. The U.S. Fish and Wildlife Service listed the Lost River sucker as endangered in 1988 under the Endangered Species Act. California designated the species as fully protected. Current population estimates suggest fewer than 10,000 individuals remain across the species' range, representing a decline of over 95% from historical levels. Primary threats include habitat loss from water diversions, poor water quality associated with agricultural runoff, competition and predation from non-native species, and climate change impacts on lake levels. Recovery efforts focus on habitat restoration, water management modifications, and removal of non-native predators from critical habitats.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.