9528 ‎(2)‎

• 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

(CDOW et al. 1996). The Cooperative Agreement for implementation of the Procedures was ,
approved by the Wildlife Commission on 19 September 1996, and by the Directors of the state
wildlife agencies in Colorado, Utah and Wyoming, and the U.S. Fish and Wildlife Service,

Region 6, on 6 November 1996 (CDOW et a1.1996). The Agreement states that the States "will '
ensure that all State and private stocking of nonnative fishes in the UCRB are in compliance with
the Procedures. This will include, but not be limited to, enacting/clarifying appropriate

regulations for stocking of public and private waters." The intent of the Procedures is "to reduce '
the potential for negative impacts on the endangered fishes in the UCRB and to ensure that their
recovery is not inhibited by controlling stocking and escapement of stocked, nonnative fish." '
Colorado addressed the requirement to "ensure that all State and private stocking of
nonnative fishes in the UCRB is in compliance with the Procedures" in January 1999 by
restricting nonnative fish stocking in waters below 6,500 feet in elevation in the Colorado,
Gunnison, White, Yampa, and Green River basins. This demarcation at 6,500 feet is found in
the Procedures (CDOW 1996) which basically state that most areas above'this elevation are '
Coldwater habitats that will not support warmwater fishes. Further, it was believed that there
were very few floodplain situations above 6,500 feet, and that those ponds present are typically
stocked with sahnonids. '
Adopted in 1999, these new regulations in conjunction with the existing lake license
permit regulations are intended to meet the intent of the Procedures. The Colorado Wildlife
Commission conditioned approval of these new stocking regulations by requiring an evaluation
of the regulations' effectiveness in achieving a biological response. The Commission will
review the overall effectiveness of these regulations, and consider the continuation or
replacement of these regulations, based in part, on the findings of this project.
The regulatory approach to nonnative fish control affects river reaches subject to one or '
more active nonnative fish removal projects, making such effects cumulative and difficult to
separate. Stocking regulations are also influenced by uncertain and uncontrolled variability in
participation, compliance and accuracy of records. Thus, the chosen approach by the Colorado '
Division of Wildlife (CDOW) was to document: (1) the extent of aquatic resources that
constitute sources of nonnative fishes and receiving waters for stocked fish, (2) waters affected
by nonnative fish control actions, (3) the distribution and composition of fish species associated '
with source and control waters, (4) the biological response of target native and nonnative fishes
to cumulative control actions within critical habitat, and (5) the extent of private waters and
businesses affected by the regulation and permit system.
Purpose and Objectives
t was to evaluate the effectiveness of Colorado's fish ,
Ultimately, the goal of this pro~ec
stocking regulations in achieving the desired biological responses offish communities within
critical habitat for endangered fishes. Primary objectives were:
(1) To determine if the administration offish stocking regulations and permits is contributing to
the reduction in riverine abundance of target nonnative fish species. t