WSP04979

• File Number: 8240.200.10.B
• Description: UCRBRIP - Riverine Fish Flow Investigations
• Basin: Colorado Mainstem
• Date: 6/1/1999
• Author: CDOW
• Title: Riverine Fish Flow Investigations 1999
• Water Supply Pro - Doc Type: Publication

Table 4. Density estimate, 95% C.I. (% of est.), and biomass estimate for the
Representative Reach and Surveyed Site at Duffy, Yampa River,
September 1998.

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Electrofishing results indicate that the SS sections (habitat mapping areas) at
both areas had somewhat different fish population characteristics than in the longer
reaches (RR). The total fish density at Sevens RR and SS was not significantly different;
however, flannel mouth sucker was significantly different at the two sites with fewer in
the SS (Table 5). At Duffy the total fish estimate in the RR was significantly different
than the SS estimate due to more WSWX in the SS section. (Table 5).

DUFFY REPRESENTATIVE REACH SURVEYED STIJDY SITE
No.1km 95% C.l KgIha No.1km 95%C.I KgIha
Total fish 411 10% 87 786 17% 141
White Sucker 244 11% 50 499 17% 98
Smallmouth Bass 45 61% 3 101 131% 7
Flannehnouth S. 30 39% 6 46 49% 8
Bluehead Sucker 21 64% 2 19 164% 2
Channel Catfish 16 77% 6 11 4
Northern Pike 17 132% 2 52 123% 5
Roundtail Chub 16 45% 3 19 196% 3
Carp 15 132% 11 14 8
Colo. Pikeminnow, 7 81% 3 25 7

Table 5. Significant difference (S.D.) for alpha 0.05 for density estimates between
the two study sites, Sevens and Duffy for the SS and RR sections.

Rep. Reach (RR) Survey Site (SS) Sevens Duffy
Species SEVENS vs. SEVENS vs. SSvs. SSvs.
DUFFY DUFFY RR RR
Total fish S.D. ad ad S.D.
Bluehead sucker S.D. ad ad ad
Channel catfish S.D. S.D. ad ad
Carp ad ad ad. ad
Colorado pikeminnow S.D. ad ad S.D.
Flannehnouth sucker S.D. S.D. S.D. ad.
Northern pike ad ad ad ad
Roundtail chub S.D. ad ad ad
Smallmouth bass ad ad ad ad
WSWX S.D. S.D. ad S.D.

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