9443

• UCREFRP Catalog Number: 9443
• Author: Bestgen, K. R., G. B. Haines, R. Brunson, T. Chart, M. Trammell, R. T. Muth, G. Birchell, K. Chrisopherson and J. M. Bundy.
• Title: Status of Wild Razorback Sucker in the Green River Basin, Utah and Colorado, Determined From Basinwide Monitoring and Other Sampling Programs.
• USFW Year: 2002.
• USFW - Doc Type: Project Number 22D,
• Copyright Material: NO

0.3) and the lower Green rivers (RK 156 and 236.7). The stocked razorback suckers captured in
1996 to 1999 (N = 25) were mostly from the same areas in the middle Green River (N = 21) and
were concentrated in the Escalante Ranch spawning bar reach; four were also captured in the
lower Green River.
Early life stages of razorback sucker have been captured at more locations than adults
since 1992, but encompassed essentially the same range (Fig. 3). The distribution of sampling
sites was relatively broad in the study area during Basinwide sampling (appendices I and II), but
fish were captured at relatively few sites. Larvae have been collected as far upstream as the
mouth of the Yampa River downstream to the lower Green River in Labyrinth Canyon. Most
razorback sucker larvae were captured in the middle Green River from the Escalante and Ouray
reaches, and in the lower Green River near the San Rafael River and in Labyrinth Canyon. Few
fish were captured in the Jensen reach or in the Green River near Green River, Utah. We also
note that a razorback sucker larva was captured in the lower Yampa River on 2 July 2000 during
drift net sampling for larvae of Colorado pikeminnow Ptychocheilus Lucius. That fish was only 9
mm TL and suggested continued spawning in that system at a relatively late time in the year.
Basinwide sampling, adults, 1996 to 1999.- A total of 83 adult fish were captured in

Basinwide sampling from 1996 to 1999 (Table 1). Of those, a minimum of 25 individuals were
of hatchery origin, assuming no loss of PIT tags. Of the remaining 58 presumptive wild fish
captured, only five of those were recaptures offish that were tagged or recaptured and released in
the period 1996 to 1999. The low number of captures and recaptures prevented any type of
abundance estimation using only fish captured in Basinwide sampling. Basinwide sampling
suggested that stocked fish were surviving and in 1999, outnumbered wild fish captured. Of 33
total fish captured in 1999, 19 (58 %) were hatchery-reared fish.
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