9688

• UCREFRP Catalog Number: 9688
• Author: Upper Colorado River Endangered Fish Recovery Program.
• Title: Nonnative Fish Control Workshop Summary, Conclusions, and Recommendations.
• USFW Year: 2002.
• USFW - Doc Type: Lakewood, CO.
• Copyright Material: NO

Population estimates did not show depletive effects from centrarchid removal
efforts in the upper Colorado River.
Studies to date did not show a measurable, lasting reduction in channel catfish
populations through mechanical-removal efforts targeting young fish. No
alternative methods were identified that would potentially improve chances for
successfully reducing channel .catfish populations through mechanical removal of
young fish. Desolation/Gray canyons is a suspected spawning reach for channel
catfish because of the abundance of large boulders and crevices used by cavity
spawners.
Data indicate that angling and electrofishing targeting subadults and adults are
effective methods for reducing channel catfish numbers in Yampa Canyon.
Yampa Canyon is a suspected spawning reach for channel catfish because of the
abundance of large boulders and crevices used by cavity spawners. It is-known
that young channel catfish produced in the Yampa River (and other tributaries)
disperse downstream into the mainstem Green River, then likely migrate back to
the tributaries as subadults to recruit into adult populations.
The group expressed the potential need for channel catfish control programs
(similar to those recommended for the Yampa River and Desolation/Gray
canyons) in portions of the Duchesne, White, and Colorado rivers.
Studies to date did not show a measurable, lasting reduction in nonnative cyprinid
populations through mechanical-removal efforts; treatment areas were rapidly re-
colonized. No alternative methods were identified that would potentially improve
chances for successfully reducing nonnative cyprinid populations through
mechanical removal.
The following recommendations resulted from the above conclusions:
Recovery Program's I&E Coordinator work with the I&E Committee and State
and local entities (e.g., Yampa Basin Partnership} to improve the message and
communications.
Revise the 1996 Nonnative Fish Stocking Procedures to simplify, clarify, and
better reflect the current state of knowledge and proposed future direction of
nonnative fish control efforts and regulations.
Discontinue reclamation of individual ponds in the Grand Valley as a Recovery
Program scope of work. Modify current scope of work to identify major source
ponds/irrigation returns and place screens to minimize escapement of nonnative
fishes to the mainstem Colorado River; explore use of isotopes as an evaluation
tool. Screen designs are available that prevent all large fish and most larvae from
escaping, and require relatively little maintenance and allow for flood overflow.
Anita Martinez (CDOW) has lead; she will work with U.S. Fish and Wildlife
Service (USFWS) Grand Junction to identify "hot spots" as sources of predaceous
centrarchids (especially largemouth bass).
Reevaluate Colorado State regulations that require screening the outflows of
individual ponds.- In particular, enforce screening of the few large source
ponds/irrigation returns.
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