7735

• UCREFRP Catalog Number: 7735
• Author: Bates, B., T. Chart and M. Moretti.
• Title: Colorado Squawfish Interagency Standardized Monitoring Program, Utah, 1986-90, Lower Green and Colorado Rivers.
• USFW Year: 1993.
• USFW - Doc Type: Publication Number 93-11,
• Copyright Material: NO

6

This increase in catch rate was result of a greater
incidence of younger age classes of fish (Figure 3). Age and
growth analysis of fish collected in 1989 indicated squawfish
between 100-250mm were primarily of the 1986 year class. Based
on their analysis and the 1990 length frequency histogram it
would appear both the 1986 and 1987 year classes were well
represented in 1990.

Conversely, on the Colorado River catch rates of Colorado
squawfish have diminished over the 5-year period (Figure 4; Table
1), where most fish were caught on the lower reach in the first 2
years. In addition to the fish collected, 23 and 13 squawfish
were observed but not captured while sampling the Green and
Colorado, respectively.

Figure 4. Colorado Squawfish Mean Catch
per Unit Effort, Colorado River, Utah

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