9532

• UCREFRP Catalog Number: 9532
• Author: Anderson, R. and G. Stewart.
• Title: Riverine Fish Flow Investigations.
• USFW Year: 2000.
• USFW - Doc Type: Fort Collins.
• Copyright Material: NO

the surveyed reaches were shorter in distance the number of fish in sample was smaller and

the result was a fewer number of recaptures. Therefore confidence intervals are higher for

the surveyed reaches, in spite of similar recapture rates. The surveyed sites in 1999 supersede

the 1998 sites because channel surveying was enlarged.

Total fish density at the Duffy site in the surveyed reach was somewhat higher than in

the longer reach, probably because the surveyed reach had a higher proportion of deep run

habitat than the longer representative reach. Density estimates for bluehead sucker,

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flannel mouth sucker, roundtail chub and Colorado pikeminnow were very similar between the

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surveyed and the long station. For the Sevens station the density of flannel mouth and

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roundtail chub were very similar for the surveyed and longer reach. However bluehead sucker

density in the surveyed site was less than half that found outside the surveyed area.

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Table 7: Density estimates with 95% C.!. and Surveyed Sites (shorter sections) at Sevens

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and Duffy, for September 1998 and 1999.
Sevens Sevens Duffy Duffy
1998 1999 1998 1999
No.lkm No.lkm No.lkm No.lkm
Total fish s.~~:::*1:~1 1138 :t24% 559 +17% 543 :f:9%
Bluehead Sucker :t:;IOOmn4~ 112 +99% 21 :f:174% 24 :f:52%
Flannelmouth S 2IoDtfA\: 371 :t26% 15 :f:49% 28 :f:58 %
....................... :f:59%
Roundtail Chub a4mO~r 36 +88% 10 +150% 22
. :. :i;f.. <;; . .:;
. . ... ... II
....':.:..:...:..........::..:...
Colo. Pikeminnow sma 9+NR . 17 :f:NR 5 :f:NR
Carp $.~~l~~g~: 61 :f:196% 9 :f:NR 2 :f:NR
Channel Catfish ;i~~~ 144 :f:NR 9:f:NR . 26 :f:NR
Small mouth Bass _':I~~: 23 +107% 74 :t131 % 70 :f:91 %
Northern Pike if9iiM:a 47 + NR 40 +123% 18 :f:NR
. . . . . . . . . , . . . . . . . . .
White Sucker t.l 214 +132 206 :t22% 178 :f:14%
White-Bluehead if 9:f:N R 38 :f:113% 22 :f:44 %
White- . +.: 1'35 :t186% 121 :t27% 148 :f:12%
Flannelmouth

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SEINING

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Fish collected by seining is presented by both total seine hauls (included fish from isolated

pools) and with isolated pools removed. It was assumed that isolated pools would not

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