7864

• UCREFRP Catalog Number: 7864
• Author: Modde, T. and E. J. Wick.
• Title: Investigations Of Razorback Sucker Distribution, Movements And Habitats Used During Spring In The Green River, Utah.
• USFW Year: 1997.
• USFW - Doc Type: Recovery Program Project No. 49,
• Copyright Material: NO

between one and three meters in depth. No tendency was observed for substrate type.
Fish found in Split Mountain Canyon were more often located in areas with larger
substrate (e.g. boulders), whereas those found in the low gradient reaches below the
canyon were found over sandy or gravel substrate.
Following stocking on 14 July, 1993, four of the five stocked fish were located
by ground contact when habitat use was recorded. Ground contact was used to locate
subadult razorback suckers in Old Charley Wash on 26 and 27 July, 1993. However,
only one fish was located on each date. An aerial flight over the wetland on 31 August,
1993 located only two fish in the wetland (40.762 and 40.792) and one fish (40.781)
near a grove of trees outside of the wetland. Due to the difficulty in locating fish at
surface elevation and the perceived problem of avian predation, the monitoring effort
was abandoned. Habitat data collected from the five observations recorded are listed
in Table 2. An aerial flight on 22 September indicated that four fish were alive, two in
Old Charley Wash and two that entered the Green River (RK 402 and 388).

DISCUSSION

Positions occupied by adult razorback sucker during the winter were less than
50 kilometers from spawning sites. However, several individuals traveled over 90
kilometers either prior to or shortly after spawning. Valdez and Masslich (1989)
reported little movement of razorback sucker during winter. Tyus and Karp (1990)
reported long-range movements between the Ouray and the Escalante spawning areas
during spring and associated them with spawning migrations.
Tyus and Karp (1990) suggested that flow and temperature influenced the
onset of spawning behavior. Telemetry data in this study corroborated their
observations and suggested that increases in discharge probably has greater influence
in initiating fish movement to the spawning sites. Spawning migration of the quillback
Carpiodes cyprinus was initiated by discharge as long as water temperatures exceeded
50C (Parker and Franzin 1991). More variation in the number of migrating white sucker
Catostomus commersoni found in a spawning tributary was explained by discharge than
temperature in Alberta, although the greatest variation was explained by the product of
the two variables (Barton 1980). The importance of increasing flows to initiate
spawning migrations has been reported for a variety of fishes (e.g. Libosvarsky 1976;
Welcomme 1985; Masse et al. 1991).
During the course of this study, both telemetry and capture data showed that
most adult razorback sucker moved downstream after spawning to tributary mouths
such as Ashley Creek, Stewart Lake Outlet, Duchesne River, and Old Charley Wash
Outlet. Many of these fish moved to the vicinity of the Ouray wetlands and the mouth of
the Duchesne River. After high flows receded, fish monitored with radio transmitters
returned upstream to the vicinity of Split Mountain Canyon. The significance of the
long-range movements observed prior to spawning is unclear. Tyus and Karp (1990)
suggested that downstream movement of razorback sucker following spawning may be

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