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sampling deep, swift, water habitat with seins and electrofishing gear. Adults are well adapted to swift current and occupy deeper, swifter, water than the young. Bottom substrate over which young roundtails are found is usually clay, soft mud, or mud and sand, but they are occasionally found among rocks, gravel or rubble (Sigler and Miller, 1963). Young roundtails were commonly found in pools below riffles and pools formed by debris on the margins of the river. The fish apparently seek pools where there is some water movement since roundtails were not often found in stillwater areas. Speckled Dace (Rhinichthys osculus) The speckled dace is widely distributed in major streams and desert springs in Utah and other parts of the interior West. Its great abundance, small size, and wide distribution make it readily available as a forage fish. The speckled dace generally does not reach a length greater than 2 in (5 cm) to 3 in (8 cm), but individuals up to 4 in (10 cm) have been captured (Sigler and Miller, 1963). Two year classes were apparent during two sampling dates (Figure 3). Each group increased in length 10 to 15 mm between sampling dates. The dace lives in a variety of habitats from swift, cold riffles of mountain streams to large, turbid, warm rivers. In the White River, dace were commonly found in water less than 1 m deep and,in riffle areas where a rubble covered bottom was present. Flannelmouth Sucker (Catostomus latipinnis) The flannelmouth is confined to but common in the Colorado River basin. The large fleshy lobes of the lower lips distinguish this species from other suckers. It spawns during the summer in the upper Colorado basin and is known to hybridize with the humpback and other suckers (Hubbs and Miller, 1953). Adults reach about 20 in (52 cm) in length. Few adults were collected during this survey. Analysis of length data on 341 flannelmouths collected in September revealed a large age group, 26 to 50 mm in length. Based on data presented by McAda (1977) for flannelmouth in the Green River, fish in this large length group were probably young-of-the-year. Adult flannelmouth typically live in pools. The few large flannelmouth captured or observed during this study were always in the relatively deep water of runs or pools. Like juveniles of other species, the flannelmouth typically live in more shallow, marginal waters of a river and in the White, were readily captured in this type of habitat. Bluehead Sucker (Pantosteus delphinus) The bluehead sucker is widely distributed in the Colorado River drainage and is particularly common in the Green River drainage. Spawning probably occurs