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

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(2) To monitor the trend in distribution and abundance indices for target nonnative fish species
in riverine habitats, and compare the indices to concurrent public/private fish stocking data.
(3) To conduct a risk analysis (RAMC 1996) of nonnative fish stocking in the UCRB in
Colorado to identify its relative significance and potential for introducing nonnative fish
species into critical habitat for endangered fishes.
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Stud~ea
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METHODS
A variety of data sources were required to depict locations of ponds and reservoirs,
including the locations of ponds by floodplain position within critical habitat for endangered
fishes along the Colorado and Gunnison rivers. Four general geographic areas were delineated to
examine nonnative fish stocking activity and encompass various levels of detail with regard to
pond abundance, fish sampling data and stocking records (Figure 1):
1) Colorado, west of the Continental Divide, the general study area.
2) Western Colorado below 6,500-feet in elevation, excluding the San Juan River basin, the
regulatory study area (technically, the new regulations do not apply to the San Juan basin, but
it was included for some data depictions and discussions).
3) The Colorado and Gunnison River corridors within and adjacent to critical habitat for the
endangered fishes, the primary study area. This included the Colorado River from river mile
240 to 152 on the Colorado River and the Gunnison River from river mile 52-0.
4) The Grand Valley reach of the Colorado River and its associated 50 and 100 year floodplains
between river miles 185-152, the intensive study area (ISA).
Overview
The overall methodology chosen for this project involved use of the Geographic
Information System (GIS) to provide a comprehensive framework for examining diverse
information. The CDOW solicited bids from potential contractors for the GIS component of this
study and selected the Wyoming Geographic Information Science Center at the University of
Wyoming in Laramie, with Nathan Nibbelink, Ph.D., as the principal investigator.
The acquisition and examination of data in this report fell into four primary categories.
These included:
1) Pond, lake and reservoir locations and associated hydrography in western Colorado.
2) Available data for fish species composition and nonnative fish control treatments in
floodplain and adjacent ponds along the Colorado River.
3) Pre- and post-regulation nonnative fish stocking data.
4) Pre- and post-regulation abundance of selected nonnative fishes in backwaters within the
Grand Valley reach of the Colorado River.