9705

• UCREFRP Catalog Number: 9705
• Author: Green River Study Plan ad hoc Committee.
• Title: Study plan for the implementation and evaluation of flow and temperature recommendations for endangered fishes in the Green River downstream of Flaming Gorge Dam.
• USFW Year: 2007.
• USFW - Doc Type: Upper Colorado River Endangered Fish Recovery Program
• Copyright Material: NO

GREEN RIVER STUDY PLAN

12

February 2, 2007

3. Razorback Sucker
a. Spawning bar complexes (Split Mountain Canyon to Desolation Canyon)
· Same as those identified for Desolation and Gray Canyons reach under
overall reach-habitat priorities above.
· Location of additional potential spawning areas in reach.
b. Flooded bottomlands (Split Mountain Canyon to Desolation Canyon)
. Same as those identified for Split Mountain Canyon to Desolation Canyon
reach under overall reach-habitat priorities above."

Green River Subbasin Floodplain Management Plan

In 2004, the Recovery Program issued Green River Subbasin Floodplain Management
Plan (Valdez and Nelson 2004). This plan was developed in order for the Recovery Program to
establish goals, identify management actions, and to gage progress on habitat restoration and
protection. Implementation of this management plan is one means by which the Recovery
Program achieves floodplain-related recovery criteria and management actions. The goal of this
plan was to provide adequate floodplain habitats for all life stages of razorback sucker,
particularly to serve as nursery areas for larvae and juveniles, for establishment and maintenance
of self-sustaining populations.

The floodplain management plan identified the following uncertainties, research needs,
and recommendations (summarized).

Uncertainties

1. Effectiveness and alternatives for the "reset theory" in which floodplains are allowed to
inundate and desiccate on a 12 or 24-month cycle to provide productive habitats for
maximum growth of razorback sucker with escapement to the river, and to periodically
kill nonnative fishes that are entrained in these habitats.

2. Entrainment of wild razorback sucker larvae is critical to species recovery, but drift
characteristics and entrainment are not well understood.

3. Growth and survival over a 12 to 24-month period must be sufficient to minimize the risk
of predation and for razorback sucker to recruit to the adult portion of the population.

4. Short-term floodplains may have little value as nurseries but may be used transiently by
large juvenile and adult razorback sucker, bonytail, and Colorado pikeminnow.

5. The reset strategy of cyclic inundation/desiccation of floodplains may enhance growth
and survival of razorback sucker and negate the effect of production of nonnative fishes
in these habitats.