WSP00173

• File Number: 8240.200.10.A
• Description: UCRBRIP Habitat Restoration
• Basin: Colorado Mainstem
• Date: 10/8/1997
• Author: UCRBRIP
• Title: Final Habitat Restoration Program FY 1998 Work Plan Part 2
• Water Supply Pro - Doc Type: Publication

4. Continue to monitor relative abundance oflarval razorback sucker in the lower
Green River.

End Product? Report on 1998 results, integrated with those from 1996 and 1997
sampling, and a revised monitoring plan based on results of this and other related
studies.

V. Study Area:

Until razorback sucker have been re-established in other rivers of the upper basin, the
basin-wide razorback sucker monitoring program is restricted to the Green River
system. Study areas are in the middle and lower Green River systems, Utah. River
miles and sampling dates are included under study methods/approach.

VI. Study Methods/Approach:

Given the present distribution and abundance of razorback sucker in the upper basin,
stockings of large juvenile and small subadult razorback, and uncertainties over methods
for effective sampling of adult, subadult, or juvenile razorback sucker, development and
implementation of the monitoring program will follow an adaptive management
strategy. As new information is acquired, the monitoring program will be revised.
accordmgly. Study objectives and methods/approach for FY-1998 may be modified
after data from FY -1997 monitoring have been analyzed and integrated with results of
FY-1996 monitoring.

Approaches for sampling razorback sucker in the Green River system were outlined in
recommendations by Muth (1995), which were based on comprehensive literature and
data reviews. These approaches and considerations were revised based on comments
from the Biology Committee and other researchers, discussions with Monitoring
Program Coordinators, and results of the 2?3 June 19971SMP meeting. Monitoring
will need to be coordinated with (or supported by) ISMP, evaluations oflevee-removal
strategies (Lentsch et al. 1995), investigations at Old Charlie Wash (Lead, Tim Modde),
and evaluations of experimental stockings. The Larval Fish Laboratory (LFL) will be
responsible for coordmating monitoring activities, integrating results/reports of
sampling efforts, preparing overall annual reports, and revising the monitoring program.

Objective 1. ?Continue to Develop and Evaluate Strategies for Effective, Standardized
Sampling of Adult Razorback Sucker in the Middle Green River and Monitor Relative
Abundance. Objective 2. ?Begin to Develop and Evaluate Strategies for Effictive,
Standardized Sampling of Adult Razorback in the Lower Green River:

Summaries of adult razorback sucker captures in the upper basin (Centralized Database
records, 1975?1995) were presented by Muth (1995) and in the FY-1996 monitoring
program scope-of-work. Effective sampling strategies for adult razorback sucker were
established in studies conducted by the U.S. Fish and Wildlife Service during 1979 to
mid?late 1980's (e.g., Tyus 1987; Tyus et al. 1987; Lanigan and Tyus 1989; Tyus and
Karp 1989, 1990). Electrofishing of active, pre-, and/or post-spawning aggregations
was the most effective sampling method, but the potential for detrimental effects on
adults, gametes, and/or subsequent offspring was recently'demonstrated in studies
conducted by the LFL (Muth and Ruppert 1996, 1997). As a result, the Recovery
Program has placed a moratorium on electro fishing over active razorback sucker
spawning areas. Therefore, other sampling methods need to be developed and evaluated
as alternatives to intensive electrofishing over active razorback sucker spawning areas.

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