Siphateles bicolor ssp. 11

High Rock Springs Tui Chub

Family: Leuciscidae · Class: Actinopterygii · Order: Cypriniformes

Conservation status: G4TX SX

The High Rock Springs Tui Chub (Siphateles bicolor ssp. 11) is a subspecies of tui chub endemic to High Rock Springs in California. This cyprinid fish represents one of several isolated tui chub populations that have evolved distinct characteristics in spring-fed habitats throughout the western United States. The taxonomic designation "ssp. 11" indicates this population's distinct genetic lineage within the broader Siphateles bicolor complex. The High Rock Springs Tui Chub exhibits typical tui chub morphology, with an elongated, somewhat compressed body and a terminal mouth. Like other tui chub subspecies, adults likely reach lengths of 100 to 300 millimeters (4 to 12 inches), though specific morphometric data for this population has not been well documented. The species displays the characteristic olive to dark coloration on the dorsal surface with silvery sides typical of the genus Siphateles. This subspecies is restricted to High Rock Springs and associated waters in California. The exact location and extent of its range within the High Rock Springs system requires further documentation, but like other spring-endemic tui chubs, its distribution is likely extremely limited to the immediate spring environment and any connected outflows. The habitat consists of spring-fed waters that provide the cool, consistent temperatures and water chemistry required by this subspecies. Spring environments typically offer stable thermal regimes and unique chemical compositions that have driven the evolutionary divergence of isolated tui chub populations. The specific habitat parameters of High Rock Springs, including temperature range, dissolved oxygen levels, and substrate composition, have not been thoroughly characterized in available literature. As with other tui chub subspecies, the High Rock Springs Tui Chub likely feeds on algae, aquatic invertebrates, and organic detritus. Spawning behavior presumably follows typical tui chub patterns, with reproduction occurring in spring or early summer when water temperatures are optimal. The species may exhibit broadcast spawning over suitable substrate, though specific reproductive timing and behavior for this population remain undocumented. The conservation status of the High Rock Springs Tui Chub is of significant concern, with a global rank of G4TX SX indicating the subspecies is presumed extinct in California (SX). This designation suggests that extensive surveys have failed to locate surviving individuals, though the population has not been formally declared extinct. The presumed extinction likely resulted from habitat degradation, water diversions, introduction of non-native species, or a combination of anthropogenic factors that commonly threaten spring-endemic fishes in the western United States. Springs are particularly vulnerable to groundwater pumping, surface water diversions, and livestock impacts that can alter or eliminate the specialized conditions required by endemic subspecies. The apparent loss of the High Rock Springs Tui Chub represents part of a broader pattern of decline among spring-endemic fishes in California and the Great Basin region. Conservation efforts for remaining tui chub populations emphasize habitat protection, water rights preservation, and genetic monitoring to prevent similar losses.

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