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n 1 1 Species accounts, Colorado pikeminnow.-Colorado pikeminnow were captured in seine samples from the lower Yampa River and the Green River in Island Park and in electrofishing and angling samples in the Green River in Lodore Canyon. The young Colorado pikeminnow captured in the lower Yampa River were found only in 1994 from 20 July to 5 August. All were collected from a backwater about 0.8 km upstream of the Green River confluence. The single juvenile Colorado pikeminnow captured from the Island Park area was in a backwater. A total of 17 Colorado pikeminnow were captured and an additional five were observed in the Green River, Lodore Canyon. All were large juveniles or adults and averaged 576 mm TL (400 - 780 mm TL; Fig. 10). Captures and observations were made throughout Lodore Canyon; two were from each of reaches 1 and 2, and six and 13 (includes a recapture) fish were from reaches 3 and 4, respectively. Colorado pikeminnow were captured in all seasons when sampling occurred including spring (late April to mid-May), summer (mid-July), and autumn (early to late September). Capture rates per hour of electrofishing were 0.41 fish/hr for reaches 1 through 4 and 0.53 fish/hr for reaches 3 and 4. The length-weight relationship calculated for Colorado pikeminnow captured in the Green River, Lodore Canyon was: Weight (kg) = 0.03908* l0o.oozsos•rL ~mm>> rz = 0.98. Predicted weight of Colorado pikeminnow from Lodore Canyon was similar to Yampa River fish that were up to 500 mm TL but was substantially higher for fish 600 mm TL or larger (Fig. 11). We detected PIT tags in two of the 17 Colorado pikeminnow we captured. The first was a 541 mm TL fish we captured, tagged, and released on 15 July 1994 at RK 559.1; no weight was obtained at initial capture. It was 576 mm TL when recaptured on 1 May 1996 at RK 558 and had a weight of 1.58 kg. We assumed this fish had about one and a half growing seasons between capture intervals, a growth rate of 23 mm/year (35 mm TL change/1.5 yr = 23.3 mm TL/yr). The second recapture originally was marked at RK 24.2 in the White River, Utah on 18 21