8071

• UCREFRP Catalog Number: 8071
• Author: Horn, M. J. and P. C. Marsh.
• Title: Production of Razorback Sucker in a Backwater at Yuma Cove, Lake Mohave, Arizona and Nevada, 1992.
• USFW Year: 1993.
• USFW - Doc Type: Tempe, Arizona.
• Copyright Material: NO

INTRODUCTION

The razorback sucker, Xvrauchen texanus, is an endangered fish

endemic to the Colorado River basin. The largest remaining

population of this unique species occupies Lake Mohave, a

mainstream Colorado River reservoir in Arizona and Nevada, where it

has been studied since impoundment of the lake in the 1950s

(Minckley 1983, Minckley et al. 1991). The adult population,

estimated to number about 60,000 fish (Marsh 1992), is comprised of

old individuals (McCarthy and Minckley 1987). Although these

reproduce annually and produce abundant larvae, the latter

disappear before attaining juvenile size and there has been no

detectable recruitment in nearly four decades (Minckley 1983,

Minckley et ale 1991). Available evidence suggests that predation

by non-native species on early life stages is among the factors

responsible for this recruitment failure (Marsh and Langhorst

1988). Because of its size and extraordinary genetic diversity

(Dowling and Minckley, in press), the Lake Mohave razorback sucker

population is a focal point for recovery of this critically

imperiled species, and attempts to prevent its extirpation are

vital to survival of the taxon.

Augmentation is considered a viable management alternative toward

perpetuation of razorback sucker in Lake Mohave. Although

successful propagation and rearing techniques have been developed

(Inslee 1982, Hamman 1987), stocking elsewhere of young fish