The historic distribution of the Owens tui chub was throughout the standing waters and low gradient reaches of the Owens River and its larger tributaries extending from the river's source springs to its terminus at Owens Lake.
The Owens tui chub is similar in appearance to the closely related Mohave tui chub. Owens tui chub are large-scaled, small, chunky fish. They are olivecolored on the dorsal surface and bluish or creamywhite below. To distinguish the Owens tui chub from other tui chub requires microscopic examination of scales and cranial bones, although DNA techniques are under development. The maximum body length is approximately eight inches. Owens tui chub spawn from March through September. Females lay adhesive eggs on vegetation or other available substrates, such as rocks and gravel. Owens tui chub eat insect larvae and, to a lesser degree, algae and detritus.
There are three existing natural Owens tui chub populations. These are at the Owens River Gorge, source springs of the Department's Hot Creek Hatchery, and a pond and ditches at Cabin Bar Ranch near Owens Dry Lake. Additional populations of Owens tui chub have been established in cooperation with land owners at BLM's Mule Spring, Little Hot Creek in Inyo National Forest, and at the University of California White Mountain Research Station owned by LADWP.
The major threats to the Owens tui chub are the presence of numerous, introduced Lahontan tui chubs with which the natives readily hybridize, and the introduction of predatory fish species, and lack of suitable habitats for reestablishment. The New Zealand mud snail is a tiny, alien species that is invading some California waters and threatening wild trout populations. The snail has already been found in both the upper and lower portions of the Owens River. Its potential impacts on the Owens tui chub are not known. Competition with and predation by trout in the Owens Gorge, geothermal and water supply development in the Hot Creek watershed, and vegetation encroachment at Cabin Bar potentially threaten existing populations. The Department has contracted with UC Davis to verify the genetic purity of tui chub populations in the Owens Valley and make genetic management recommendations.
(Excerpted from DFG publication, Species Accounts - Fish (PDF)