Siphateles bicolor thalassinus

Goose Lake Tui Chub

Family: Leuciscidae · Class: Actinopterygii · Order: Cypriniformes

Conservation status: G4T2T3 S2

The Goose Lake Tui Chub is a subspecies of the bicolor tui chub endemic to the Goose Lake basin in northeastern California and south-central Oregon. Adults typically measure 10 to 20 cm (4 to 8 inches) in total length, with a deep, laterally compressed body characteristic of the Cyprinidae family. The species displays the typical tui chub coloration with a silvery body, darker dorsal surface, and subtle bronze or copper tones along the sides. Like other tui chubs, this subspecies has a terminal mouth, pharyngeal teeth adapted for crushing, and a slightly forked tail fin. Historically, the Goose Lake Tui Chub occurred throughout the Goose Lake basin, which spans the border between Modoc County, California, and Lake County, Oregon. The subspecies was endemic to Goose Lake itself and its tributary streams, including the Pit River drainage system in this region. Current distribution has been significantly reduced from historical ranges, with populations now fragmented and restricted to smaller areas within the original basin. This subspecies inhabits lacustrine and slow-moving riverine environments within the Goose Lake basin. They prefer areas with moderate depths, often associating with submerged vegetation and rocky substrates. Adults typically occupy deeper waters while juveniles and smaller individuals school in shallower areas near shorelines. The species shows tolerance for varying water chemistry conditions that can occur in closed basin lake systems, including fluctuating salinity and alkalinity levels. Goose Lake Tui Chubs are omnivorous, feeding on aquatic insects, larvae, small crustaceans, algae, and detritus. Spawning typically occurs in spring when water temperatures rise, with fish moving into tributary streams or shallow lake areas with suitable substrate. Females deposit adhesive eggs on vegetation or rocky surfaces. The species exhibits schooling behavior, particularly among juveniles and smaller adults, while larger individuals may be more solitary. The Goose Lake Tui Chub currently holds a Global/State Rank of G4T2T3 S2, indicating the subspecies is imperiled to vulnerable globally and imperiled in California. This ranking reflects significant population declines and habitat degradation within the Goose Lake basin. Primary threats include habitat modification from water diversions, introduced competing fish species, and periodic drying of Goose Lake during drought cycles. The closed basin nature of Goose Lake makes it particularly susceptible to water level fluctuations and water quality changes. Climate change poses additional challenges through altered precipitation patterns and increased evaporation rates. Although not federally listed, the subspecies' conservation status indicates ongoing concern for its long-term viability. Conservation efforts focus on maintaining adequate water levels in Goose Lake and protecting remaining spawning habitat in tributary streams. Continued monitoring of population trends and habitat conditions is essential for the subspecies' persistence in this unique Great Basin ecosystem.

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