8178

• UCREFRP Catalog Number: 8178
• Author: Anderson, R. and G. Stewart.
• Title: Riverine Fish Flow Investigations.
• USFW Year: 1999.
• USFW - Doc Type: Fort Collins, CO.
• Copyright Material: NO

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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, tlannelmouth 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).

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

DUFFY REPRESENTATIVE REACH SURVEYED STUDY SITE
No./km 95% C.l KgIha No./km 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
Flannelmouth 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. n.d n.d S.D.
Bluehead sucker S.D. n.d n.d n.d
Channel catfish S.D. S.D. n.d n.d
Carp n.d n.d n.d n.d
Colorado pikeminnow S.D. n.d n.d S.D.
Flannelmouth sucker S.D. S.D. S.D. n.d
Northern pike n.d n.d n.d n.d
Roundtail chub S.D. n.d n.d n.d
Smallmouth bass n.d n.d n.d n.d
WSWX S.D. S.D. n.d S.D.