Laserfiche WebLink
50 <br />continues to be modified by man (Miller, 1961). The young of this species <br />and of the Colorado squawfish are similar except for a prominent black spot <br />on the caudal peduncle of the squawfish juvenile. Adults of the two species <br />can be easily distinguished. During spawning in late spring, breeding males <br />are reddish on the sides of the head and body, below the lateral line. <br />Normal size of the roundtail adult is 8 in (21 cm) to 13 in (34 cm). In <br />this study, lengths were measured and within season growth of age groups <br />zero to two was readily evident from July to Sepember, 1978 (Figure 24). <br />Little growth was added over the 1978-79 winter period. A weight-length <br />relationship (r2 = 0.76) was also found using data from 113 fish and was <br />as follows: Length in millimeters = 2.5 (weight in grams) + 79.5. The <br />appearance of recently hatched fry during mid-August'(Figure 24b) is some- <br />what later than that reported for the roundtail population in the Green River <br />(Vanicek and Kramer, 1969); however, general growth patterns for each age <br />group were similar. An analysis of representative scale samples from fish <br />of the first three age groups showed that age group 0 and 1 were scaleless; <br />age group 2 had scales but no annuli. This finding agrees with that of <br />Vanicek and Kramer (1969). The relatively low number of larger fish in the <br />White River collection may have been due to gear selection and/or the dif- <br />ficulty in sampling deep, swift, water habitat with seins and electrofishing <br />gear. Adults are well adapted to swift current and occur in deeper water <br />than the young which are found in more shallow quiet areas of a stream. <br />Bottom substrate over which young roundtails are found is typically clay, <br />soft mud, mud and sand, or occasionally rocks, gravel or rubble (Sigler and <br />Miller, 1963). Young roundtails were commonly found in pools below riffles <br />and pools formed by debris on the margins of the river. The fish apparently <br />seek pools where there is some water movement since roundtails were not <br />often found in stillwater areas.