7406 - Laserfiche WebLink

Home Browse Search

Razorback suckers in the upper Green River, Utah, represent the largest remaining concentration in the UCRB but are rarer in this area than the federally endangered Colorado squawfish (Tyus 1987, Tyus et al. 1987, Lanigan and Tyus 1989). Lanigan and Tyus (1989) estimated that 948 razorback suckers (95$ confidence interval, 758-1,138) occurred in the Upper Green River, based on capture- recapture data from 1980 to 1988. In the same period, only 13 razorback suckers were captured (1 recapture) in the Green River downstream of the Duchesne River, a population estimate was not attempted for that area. Young razorback suckers were very rare in collections from the Green River. Holden (1980) reported collecting young razorback suckers in the Green River, Utah, but did not preserve any specimens. Tyus et al. (1987) reported capture of larval suckers (tentatively identified as razorback suckers by D.E. Snyder, Larval Fish Laboratory, CSU) near a spawning area in the Green River in 1984. Recent records of razorback suckers in tributaries of the Green River are also rare. Surveys of the White River (Carlson et al. 1979, Lanigan and Berry 1981, Martinez 1986, Chart 1987) and San Rafael River (McAda et al. 1980) failed to reveal razorback suckers, although one hybrid razorback x flannelmouth sucker was collected in the White River (Lanigan and Berry 1981). Records of razorback suckers in tributaries and other seasonally flooded, off-channel habitats, were often associated with springtime spawning movements (Tyus 1987, Tyus and Karp in press). 25