9528

• UCREFRP Catalog Number: 9528
• Author: Martinez, P. and N. P. Nibbelink.
• Title: Colorado Nonnative Fish Stocking Regulation Evaluation.
• USFW Year: 2004.
• USFW - Doc Type: Grand Junction, Laramie.
• Copyright Material: NO

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into Lake Mohave may provide insigh# into the inefficacy of stocking small
numbers of fish into large systems (Minckley and Thorson 2002).
3. Related to the previous issue, success of the program also relies on the
ability to define what habitats within the subunits are used by the fish. In Lake
Mohave we have the advantage of 20 years of data on the known spawning
areas, and are able to observe them in these locations each year. For most of
the other subunits, we do not have information on historically used habitats, or
those that would most likely be used. In order to identify these habitats in an
effective manner, we must be able to contact a large number of individuals. Our
ability to assess the preferred habitats, and to devise management for those
areas to foster recruitment opportunities, will rely on these data.
4. Historic population sizes were large (Minckley et al. 2003); however, in
today's river the actual population size that would be sufficient to take advantage
of management actions that foster recruitment is unknown. The population size
that each subunit could support is unknown. Stocking large numbers of fish into
the subunits over time will increase population sizes and enable us to evaluate,
through monitoring, when these levels have been reached and how those levels
relate to the Recovery Goals.
Strategy 2: Isolated Habitats
The second strategy involves the use of natural, semi-natural, or newly created
backwaters or lakes dedicated for use of one or more species. These isolated
waters must be able to support a healthy fish population and be isolated from
other waters to prevent invasion by nonnative fishes. Specific management
activities will be determined by the habitat and species. At a minimum,
management will consist of tracking the development of the native fish
population and allowing selection to act. In other cases, a more aggressive
management plan will be used to better ensure the success of these habitats
while affecting natural processes as little as possible. Two habitat types are
proposed for the second strategy:
' 1. Long-term habitats. These wild habitats are designed to develop the
genetic resource, establish self-sustaining populations, and mimic the
historic backwater habitat conditions of the lower river. The original stocks
' would be wild fish, or the best genetic stock from hatchery production.
Management of these habitats would be minimal but would be done if

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