North Platte River Fish Survey Casper to the Nebraska State Line

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North Platte River fish Survey March 1999 Wage LL E. K Wilkens State Park - Backpack. —A total of 109 fish of 8 species was captured with longnose dace comprising nearly 70 percent of the catch, followed by juvenile and subadult longnose sucker (Catostomus catostomus) (9 percent), and emerald shiner (Notropis atherinoides) (8 percent). The remainder of the catch consisted of brown trout (Salmo trutta) (5 percent), fathead minnow (Pimephales promelas) (3 percent), red shiner (Cyprinella lutrensis) (3 percent), sand shiner (Notropis stramineus) (2 percent), and white sucker (Catostomus commersoni) (1 percent). The substrate consisted mostly of coarse gravel, small boulders, and large cobbles. The sample reach was 95 percent run and about 5 percent riffle. Figure 2 shows the map of the sample site. Cole Creek-Bridge (downstream) - Backpack.— Two backpack sample sites were selected at this site, one extending 300 in downstream from the Cole Creek Bridge and the other extending 300 in upstream. A total of 48 fish of 7 species was captured at the downstream site, with 33 percent of the catch consisting of longnose dace, 13 percent sand shiners, and 10 percent juvenile white suckers. Smaller numbers of juvenile white suckers, red shiners, and brown trout were also captured. Two brassy minnows (Hybognathus hankinsoni) were also collected —the only two individuals of this species collected in this March 1999 sampling effort. Baxter and Stone (1995) indicate this species is found in the tributaries of the North Platte River. Their presence in the mainstem as well as their scarcity in our samples may indicate an unusual finding. They were collected and preserved for later validation. Habitat at this site consisted of 95 percent run and 5 percent riffle. The predominant substrate was silt with a mix of cobble of various sizes and gravel. Abundant moss was observed on the cobbles. The study site map is found in Figure 3. Cole Creek Bridge (upstrean2) - Backpack. —This site consisted of 80 percent silt with a scattering of small boulders, cobbles, and gravel. The fish community was much different, probably a result of the silt substrate. Only 25 fish were captured, possibly due to the difficulty in sampling in deep silt and mud. Twenty -four fish were longnose dace with one emerald shiner. Cole Creek Bridge to Monkey Hill Bridge - Raft.— Compared to raft sample sites further downstream, this site had a cleaner substrate (less silt) and fewer common carp, but overall fewer total fish captured (166) for the extensive level of effort (11,694 seconds in 11.1 km). Primary habitat in this reach consisted of 85 percent main channel and 15 percent secondary channel. Secondary habitat consisted of approximately 10 percent riffle, 85 percent run, and 5 percent pool. Substrate consisted of a mix of large boulders (15 percent), large and small cobbles (20 percent), coarse and fine gravel (20 percent), and 45 percent sand. The catch was comprised of 27 percent common carp, 17 percent longnose suckers, 8 percent longnose dace, 7 percent rainbow trout (Oncorhynchus niykiss), and 4 percent brown trout. Sand shiners comprised 1 percent. Trout in this reach were robust and appeared to be free of disease. Figure 3 shows the study site map. Figures 4 and 5 show the habitat in this reach. Results