Siphateles bicolor mohavensis

Mohave tui chub

Family: Leuciscidae · Class: Actinopterygii · Order: Cypriniformes

Conservation status: FP · Endangered · G4T1 S1

The Mohave tui chub (Siphateles bicolor mohavensis) is a small freshwater cyprinid fish endemic to the Mojave River system in southern California. Adults typically measure 76 to 127 mm (3.0 to 5.0 inches) in total length, with a maximum recorded length of 152 mm (6.0 inches). The body is deep and laterally compressed with a moderately large head and terminal mouth. Coloration varies with age and environment: juveniles and adults in clear water display silver sides with a dark lateral stripe, while individuals in turbid waters appear more golden or brassy. The dorsal fin contains 8 to 10 rays, and the anal fin has 7 to 9 rays. Historically, the Mohave tui chub occurred throughout the Mojave River drainage system in San Bernardino County, California, from the headwaters near Cajon Pass downstream to the terminal lakes in the central Mojave Desert. The species originally inhabited perennial reaches of the Mojave River and its tributaries, as well as natural sink areas including Lake Mojave (now beneath Lake Mohave reservoir). Currently, wild populations persist only in isolated springs and small tributary streams, primarily in the upper watershed. The species inhabits desert springs, spring-fed pools, and slow-moving stream reaches with water temperatures ranging from 4 to 34 degrees Celsius (39 to 93 degrees Fahrenheit). Mohave tui chubs prefer areas with aquatic vegetation, rocky substrates, and depths ranging from 0.3 to 2.1 meters (1 to 7 feet). They demonstrate exceptional tolerance for high water temperatures and salinity levels compared to other native California fish species. Mohave tui chubs are omnivorous, feeding on algae, aquatic invertebrates, plant material, and detritus. Spawning occurs from March through August, with peak activity during April and May when water temperatures reach 15 to 20 degrees Celsius (59 to 68 degrees Fahrenheit). Females scatter adhesive eggs over vegetation and substrate, with clutch sizes ranging from 200 to 2,000 eggs depending on female size. The species exhibits schooling behavior, particularly juveniles, and can live up to 4 years in optimal conditions. The U.S. Fish and Wildlife Service listed the Mohave tui chub as endangered in 1970, making it among the first fish species protected under federal legislation. California Department of Fish and Wildlife notes taxonomic confusion, as the species has been listed under multiple scientific names: federally as Siphteles mohavensis, by California as Gila bicolor mohavensis, and in the state's Fully Protected statute as Gila mohavensis. Primary threats include habitat loss from water diversions, groundwater pumping, introduction of non-native fish species, and habitat degradation from livestock grazing and recreation. Recovery efforts have focused on habitat restoration, non-native species control, and establishment of refuge populations. Despite intensive management, wild populations remain critically low, with fewer than 500 adults estimated across all natural habitats as of recent surveys.

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