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Last modified
7/14/2009 5:02:36 PM
Creation date
5/18/2009 12:09:01 AM
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UCREFRP
UCREFRP Catalog Number
9552
Author
U.S. Fish and Wildlife Service.
Title
Management Plan for the Big-River Fishes of the Lower Colorado River Basin
USFW Year
2004.
USFW - Doc Type
amendment and supplement to the Bonytail, Humpback chub, Colorado pikeminnow, and Razorback sucker Recovery Plans.
Copyright Material
NO
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<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />1 <br />~` <br />into Lake Mohave may provide insight into the inefficacy of stocking small <br />numbers of fish into large systems (Minckley and Thorson 2002). <br />3. Related to the previous issue, success of the program also relies on the <br />ability to define what habitats within the subunits are used by the fish. • In Lake <br />Mohave we have the advantage of 20 years of data on the known spawning <br />areas, and are able to observe them in these locations each year. For most of <br />the other subunits, we do not have information on historically used habitats, or <br />those that would most likely be used. In order to identify these habitats in an <br />effective manner, we must be able to contact a large number of individuals. Our <br />ability to assess the preferred habitats, and to devise management for those <br />areas to foster recruitment opportunities, will rely on these data. <br />4. Historic population sizes were large (Minckley et al. 2003); however, in <br />today's river the actual population size that would be sufficient to take advantage <br />of management actions that foster recruitment is unknown. The population size <br />that each subunit could support is unknown. Stocking large numbers of fish into <br />the subunits over time will increase population sizes and enable us to evaluate, <br />through monitoring, when these levels have been reached and how those levels <br />relate to the Recovery Goals. <br />Strategy 2: Isolated Habitats <br />The second strategy involves the use of natural, semi-natural, or newly created <br />backwaters or lakes dedicated for use of one or more species. These isolated <br />waters must be able to support a healthy fish population and be isolated from <br />other waters to prevent invasion by nonnative fishes. Specific management <br />activities will be determined by the habitat and species. At a minimum, <br />management will consist of tracking the development of the native fish <br />population and allowing selection to act. In other cases, a more aggressive <br />management plan will be used to better ensure the success of these habitats <br />while affecting natural processes as little as possible. Two habitat types are <br />proposed for the second strategy: <br />' 1. Long-term habitats. These wild habitats are designed to develop the <br />genetic resource, establish self-sustaining populations, and mimic the <br />historic backwater habitat conditions of the lower river. The original stocks <br />' would be wild fish, or the best genetic stock from hatchery production. <br />Management of these habitats would be minimal but would be done if <br />a <br /> <br />9 <br /> <br />
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