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17 <br />was conducted 5 weeks (35 days) later in 1981 than in 1983, but <br />sampling actually began 10 days later (August 22) in 1983 than in <br />(August 12) 1981. The large percentage of roundtail chub and <br />speckled dace in 1983 collections in the <20-n total length (TL) <br />size category indicates that they had recently spawned. Small <br />percentages of red shiner and fathead minnow in the <20-nn-TL size <br />category indicate that spawning was just beginning or reproductive <br />conditions were not favorable. Also present in 1983 seine <br />collections were mosquitofish (Gambusia affinis), green sunfish <br />(Lepomis cyanellus), Colorado squawfish, and carp which were not <br />collected in this area in 1981. The high flow levels of 1983 <br />breached many gravel pit dikes, and the river channel now flows <br />through many previous gravel pits. As a result, species which <br />normally inhabit these areas were transported into the riverine <br />environment. <br />Electrofishing samples for 1983 were similar to those <br />collected in 1981. The same four species (flannelmouth sucker, <br />bluehead sucker, carp, and roundtail chub) dominated collections in <br />both years. However, in 1983, small numbers of channel catfish, <br />black bullhead (Ictalurus punctatus), largemouth bass (Micropterus <br />salmoides), green sunfish, and white sucker (Catostomus commersoni) <br />were also collected. This was probably due to sampling of gravel <br />pit areas which had become part of the main channel <br />(Figures 3 and 4). <br />Effects of the high flow levels of 1983 were likely beneficial <br />to native species on the Colorado River by flushing spawning areas <br />and unique habitats such as the Black Rocks area near the Colorado <br />- Utah border (Figure 5). Native species may have been given a