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2 Prairie Naturalist 26(1): March 1994 We compared the composition of the catch and catch rates of fishes between D nets and conventional round nets in a small river in eastern Wyoming. We hypothesized that the D nets would have a higher catch per unit effort (CPUE) for several fish species than round nets. Here we report the catches with the two nets during the summers of 1991 and 1992. STUDY AREA The Laramie River originates in north central Colorado and flows northeast- erl y through Albany. Platte. and Goshen counties in Wyoming to its confluence with . the North Platte River. This study was conducted between Grayrocks Dam and the confluence with the North Platte River. a river reach of 20.4 Ian (Fig. 1). Down- stream from Grayrocks Dam the river has a mean width of 18 m. a mean depth of . 0.3 m. and a mean water velocity of 0.2 m/s (patton 1993). The substrate is dominated by silt. but gravel and sand are abundant in many portions of the reach. A riffle-pool sequence is distinct except in small impounded reaches fonned by water diversion dams. Cover in the fonn of undercut banks. overhanging vegetation. woody debris. or boulders is scarce. Immediately downstream from Grayrocks Dam. the minimum flow is main- tained at 1.1 m3/s from October through April and at 1.1 m3/s or 75% of the natural flow from May through September. Water temperatures exceed lOoC from May to October. and the maximum temperature is 200C (patton 1993). Riparian vegetation consists of willows (Salix spp.). cottonwoods (Populus spp.). box elder (Acer negundo). and Russian olives (Eleagnus spp.). Uplands are dominated by a variety of shrubs and grasses. w -<I- E 1 km ==-- N .. I G reyrocks Reservoir o Figure 1. The Laramie River between Grayrocks Dam and the North Platte River and the location of the eight sampling sites.