Freshwater fishes of Mojave River, California: past and present

Authors: Sujan M. Henkanaththegedara, Jeffrey A. Seigel, Debra L. Hughson, Steve Parmenter, Matthew Huffine, Craig A. Stockwell

Year: 2008 (xl)

Abstract

The Mojave River, California historically was inhabited by only one native fish, the Mohave tui chub, Siphateles bicolor mohavensis. This species was extirpated from the Mojave River by the 1960’s and currently persists in four highly modified isolated habitats. Non-native fishes have entered the Mojave River watershed through a combination of deliberate introduction, and incidental to inter-basin connection via the California Aqueduct. Arroyo chub, Gila orcutti appeared in the Mojave River in 1930’s, presumably as a released bait fish and hybridized with native Mohave tui. By 2002, 23 non-native species were reported in the Mojave River drainage. We conducted surveys to determine the existing fish species in the middle and lower reaches of the river (respectively Mojave Narrows and Afton Canyon), in order to assess the suitability of the river for a potential reintroduction of Mohave tui chub. We did not observe S. b. mohavensis in either place. We found a total of six exotic species which belong to five families (Cyprinidae, Gasterosteidae, Ictaluridae, Centrarchidae and Poeciliidae) and some presumed hybrids between existing cyprinids. Two of these species occurred in Afton Canyon with one species dominating the catch, while all six were present in Mohave Narrows.