9552

• 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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1. A genetic refuge (e.g:,~n Lake Mohave, Lake Havasu, or other
suitable locations) is maintained over a 3-year period beyond
downlisting.
2. Two self-sustaining populations (e.g., mainstem and/or
tributaries are maintained over a 3-year period beyond
downlisting, starting with the first point estimate acceptable to
the Service, such that for each population:
a. The trend in adult (age 4+; >250 mm TL) point estimates
does not decline significantly, and
b. Mean estimated recruitment of age-3 (150-249 mm TL)
naturally produced fish equals or exceeds mean annual
adult mortality, and
c. Each point estimate exceeds 4,400 adults (MVP).
Four self-sustaining populations (minimum viable population
of 4,400 adults); two in the upper basin and two in the lower
basin.
Management Strategies: These Recovery Goals will be met
through the use of Strategy 1: Augmentation.
Colorado Pikeminnow
Current Status and Recovery Efforts: Wild Colorado Pikeminnow are
extirpated from the lower basin. This species occurred in large numbers
in the lower river prior to its development for power generation and the
introduction of nonnative fishes (Mueller and Marsh 2003). Colorado
Pikeminnow have been reintroduced to the Salt and Verde rivers as
experimental non-essential populations, or 10(j) populations. In amending
the Endangered Species Act in 1982, Congress added section 10Q) to
provide administrative flexibility for selectively applying the prohibitions of
the Act to experimental populations of listed species. This section
authorizes the treatment of an experimental population as "threatened"
even though the donor population from which the experimental population
came is listed as endangered. Treatment of the experimental population
as threatened enables the use of less restrictive taking prohibitions under
the authority of section 4(d) of the Act. Experimental populations that
have been determined to be non-essential to the continued existence of a
species in the wild and are not located within a unit of the National Park
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