9499

• UCREFRP Catalog Number: 9499
• Author: Osmundson, D. B.
• Title: Removal of Non-native Centrarchids from Upper Colorado River Backwaters, 1999-2001
• USFW Year: 2003.
• USFW - Doc Type: Summary of Results.
• Copyright Material: NO

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River miles
Figure 2. Total number of non-native fish caught and removed from backwaters by two-mile
river segments using barge electrofishing, 1999-2001. BB: black bullhead; BC: black crappie;
CP-A: adult common carp; CP-J: juvenile common carp; GS: green sunfish; LG: largemouth
bass; WS: white sucker.
148) consistently contained largemouth bass. For the entire target reach, total catch and
average catch per backwater was always higher in the fall than in the preceding spring and
catch rate peaked in fall of 2000 (Fig. 3). Total catch of largemouth bass in each of the six
capture periods ranged from 85 to 1,642 individuals. Captures using the barge accounted for
86% of the total three-year catch, or 82-94% of the catch in each of the six capture periods.
Most of the largemouth bass captured were relatively small: 83-96% (depending on the
capture period) were between 50-174 mm long (Fig. 4). Individuals as large as 225 mm TL
were captured in all 6 seasonal efforts. Larger individuals (225-387 mm) were mostly captured
during spring of 2000 and 2001 (Fig. 4), and these were primarily from six backwaters: one at
rm 147, two backwaters near rm 154 and three in the 15-mile reach (rm 175.7, 180.5, and
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