Laserfiche WebLink
<br />8-day period, flows measured at the Palisade gage approximately 0.3 mile <br />downstream of the diversion dam ranged from 1,300 cfs on the 19 and 20 of August <br />to 1,580 cfs on the 22 and 23 of August. <br /> <br />Forty-six native and nonnative fish were recaptured downstream of the <br />diversion dam. Forty were native fish and six nonnative fish. This was 2.5% of <br />the total number of all fish either PIT tagged, floy tagged, or fin clipped. Of <br />the 1,128 non-endangered native fishes (flannelmouth and bluehead sucker, and <br />roundtail chub) that were PIT tagged, 31 were recaptured downstream of the <br />diversion dam, a 2.7% recapture rate. Twenty-seven flannelmouth sucker were <br />recaptured along with nine bluehead sucker, and four roundtail chub. Of the 40 <br />native fish that were recaptured, 31 had been PIT tagged and nine had been fin <br />clipped. The recapture rate for the number of native fish PIT tagged (1,128; <br />2.7%) was sl ightly higher than the number of native fish that had been fin <br />clipped (470; 1.9%). Of 203 carp and white sucker initially floy tagged, three <br />carp and three white sucker were recaptured (3.0% recapture rate). None of the <br />two rainbow trout, 18 brown trout, or 28 hybrid sucker marked were recaptured. <br /> <br />Twelve species and three hybrids (Catostomidae) were collected during this <br />study (Appendix Table A.1.). Twenty-seven channel catfish were caught during the <br />I-year study; seven were collected upstream of the GVIC Diversion Dam. Sixty-one <br />mountain whitefish were collected--50 upstream of the diversion dam. Five sub- <br />adult smallmouth bass and one sub-adult largemouth bass were also collected. <br /> <br />During a similar 7-month study to determine if a grade-control structure <br />constructed on the Yampa River near Craig, Colorado, would impede movements of <br />Colorado pikeminnow, Masslich (1993) reported that native and nonnative fishes <br />moved both up- and downstream through a man-made notch composed of varying sizes <br />of boulders and cement. He used mark and recapture techniques similar to those <br />used in this study. He reported 25 fish representing two species of native <br />fishes (flannelmouth sucker and bluehead sucker) that had been PIT tagged and <br />three species of nonnative fishes (northern pike, white sucker, and smallmouth <br />bass) that had been Floy tagged moved either up- or downstream through this notch <br />created to pass fish. <br /> <br />Masslich (1993) PIT tagged 249 native fish and Floy tagged 1,095 nonnative <br />fish. He reported recapture rates much higher than those reported during the <br />GVIC evaluation. Of 1,344 fish tagged during his study, he recaptured 242 Floy- <br />tagged fish and 23 fish that had been PIT tagged for an overall capture rate of <br />19.7%. <br /> <br />Endangered Fish <br /> <br />Caotures <br /> <br />A total of 19 adult Colorado pikeminnow were captured during this <br />evaluation (Appendix Table D.l.). Ten of these were captured upstream of the <br />GVIC Diversion Dam between 19 August and 24 September. However, it is unknown <br />whether these fish used the newly-constructed fish passage notch at the diversion <br />dam or simply passed over the diversion structure when it was inundated during <br />spring runoff. Eight of the ten fish captured upstream of the diversion dam had <br /> <br />10 <br />