Bonneville Cisco

The mouth of the Bonneville cisco is terminal, with the lower jaw slightly extending past the upper jaw. The caudal fin is deeply forked. Normally, the scales of Bonneville cisco are light silver but may become golden, brassy, or yellow during spawning. The Bonneville cisco is generally less than 7.5 in (190 mm) in total length but has been reported up to 8.6 in (220 mm). Age estimation suggests that Bonneville cisco achieve maximum growth in the first two years of their life and can live over five years.

The Bonneville cisco is only found in Bear Lake along the northern Utah-southern Idaho border. Bones of Bonneville cisco have also been identified in Homestead Cave, Utah where ancient Lake Bonneville once existed. Fishery managers attempted to introduce Bonneville cisco into Flaming Gorge Reservoir to provide additional forage to other gamefish, but stocking was unsuccessful at establishing a population. Within Bear Lake, Bonneville cisco can be found at all depths but show preference for cold water, specifically water below 59 °F (15 °C).

Bonneville cisco predominantly prey upon small crustaceans such as Epischura and Bosmina and insects such as chironomids.