WSP04463

• File Number: 8460.500
• Description: Platte River Recovery Plan
• Basin: South Platte
• Date: 6/1/1997
• Author: Colo Div of Wildlife
• Title: Inventory and Status of South Platte River Native Fishes in Colorado
• Water Supply Pro - Doc Type: Publication

Objectives of the project were:

1) To compile the available historic database on presence, distribution and abundance of
native fish species in the South Platte River Basin into computerized database files;

2) To conduct inventory throughout the South Platte mainstem and tributaries to assess
status and population trends of native fish species; and

3) To determine management strategies for individual species, guilds, or critical habitat types.

Complementary to this emphasis on the status of the native fishes, the CDOW developed
and approved a Long Range Plan for the agency (CD OW 1994), which emphasizes the
determination of status of all Colorado's wildlife species (Goal 4), and proactive conservation of
wildlife species that may be at risk of becoming threatened or endangered (Goal 5). This report
serves as the culmination of the 3-year inventory project and contributes to the achievement of
these Long Range Plan goals.

METHODS

Study area
The South Platte River Basin includes almost 60,000 km2 in drainage area, and covers
much of the north-central and northeastern portions of Colorado (Figure 1). Sampling was
targeted at the mainstem river and tributary streams within the transition! Front Range (<1,980
km in elevation) and eastern plains zones of the basin. The study area included 18 U.S.G.S.
hydrographic units representing smaller tributary drainages within the basin. The transition and
plains streams were targeted for fish collections to allow comparisons with historic data collected
in 1978-1980 by Propst (1982), which represents the' most comprehensive past record offish
distribution and abundance data in terms of geograpHic scope.

Field sample site selection
Sampling was conducted only in natural stream courses, though there is potentially
additional habitat for native species in manmade irrigation canals, stock ponds, gravel pits, natural
lakes, and reservoirs. Initially, a series of sampling sites was located at 3 to 5 km intervals from
the downstream terminus of each stream (Figure 2).! Site placement and frequency were
somewhat dependent upon access. Where possible, .historic collection sites were included in this
sampling effort. Each perennial tributary branching from the larger stream was sampled as a
separate, smaller drainage basin. The main channel of each stream or river was sampled at least
once between confluences of major tributaries. A well-developed county road system enabled
most streams to be sampled at roughly 1.6 km intervals. The largest rivers (South Platte, Cache
la Poudre, St. Vrain and Big Thompson rivers), were sampled less frequently, but samples were
taken at least every 8 km. Sampling in the greater Denver metropolitan area and surrounding

2

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I