WSP07684

• File Number: 8240.200.10.B
• Description: UCRBRIP Annual Report
• Basin: Colorado Mainstem
• Date: 12/22/1997
• Author: UCRBRIP
• Title: 1997 Annual Reports Package Part 3
• Water Supply Pro - Doc Type: Publication

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monitoring program for Colorado River miles 109.6 to 3.0 above the confluence with
the Green River. The specimens have been cataloged (LFL 30529-30711) and are
stored as part of the Larval Fish Laboratory collection for voucher and future study.

The preserved portions of these collections contain 7,696 fish (an average of 140
specimens per collection) representing 9 species (page 10). About 99.5% of the fish
are non-native. Sand shiner, red shiner and fathead minnow respectively account for
41 %, 32%, and 16% of the fish, all but 45 specimens. Other non-native species
represented, each by only one to two specimens, are mosquitofish, plains killifish, and
green sunfish. Six chub (Gila spp.) and no Colorado squawfish were preserved.
Remaining native species are bluehead sucker and speckled dace.

(c) Fall Seine Collections, Colorado and Lower Green Rivers, September 24-27, 1996.

This set consists preserved fish from 81 collections taken during the 1996 fall
monitoring program-34 from the Colorado River in Colorado (river miles 184.6-
138.9),22 from the Colorado River in Utah (river miles 108.8-3.3 above the
confluence with the Green River), and 25 from the lower Green River in Utah (river
miles 119.5-1.3). The specimens have been cataloged (LFL 30712-31084) and are
stored as part of the Larval Fish Laboratory Collection for voucher and future study
(e.g., identification of humpback chub).

In all, the collections received contain 38,175 preserved fish (an average of 471
specimens per collection) representing 17 species. Nearly 99% are non-native. Of all
fish, 99% are cyprinids (93% of all fish in the Colorado reach of the Colorado River,
nearly 100% in the Utah reach of the Colorado River, and nearly 100% in the Green
River). By species, red shiner, sand shiner, and fathead minnow respectively account
for 50%, 30%, and 18% of the fish-53%, 19%, and 17% in the Colorado reach of
the Colorado River; 26%, 43%, and 31 % in the Utah reach; and 71 %,22%, and 7% in
the Green River. This year, preserved collections include black crappie and bluegill
(Colorado reach); none were preserved in the 1995 collections.

These preserved collections include more native chub and Colorado squawfish than in
1995 and many more than in 1994. All 212 chub in 1996 collections were taken from
the Colorado reach of the Colorado River. They range in size from 25 to 58 mm TL
(total length) and all but 46 have 9 dorsal and 9 anal fin rays suggesting that most are
roundtail chub. Most others have 10 anal fin rays and one also had 10 dorsal fm rays
suggesting the possibility of humpback chub and even bimytaiL Two specimens have
9 dorsal and 8 anal fin rays, and 11 specimens have 8 dorsal and 9 anal fin rays. No
preserved Colorado squawfish were taken from the Colorado reach of the Colorado
River, 41 were taken from the Utah reach, and 54 from the Green River (only 8
preserved from the Green River in 1995). Preserved Colorado squawfish range in
size from 20 to 70 mm TL.

(2) Aspinall Collections.

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