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1 1 Elkhead Creek Aquatic Resource Report Miller Ecological Consultants, December 5, 1996 Site 2 A native fish, speckled dace, was the most abundant and represented 29.3% of the total fish captured at Site 2 (Table 2). The only native fish captured at Site 2 but not at Site 1 was the roundtail chub (Gila robusta). Native fish comprised 56% of the species collected at Site 2 but only 48% of the individual specimens. Non-native fish were slightly more numerically dominant at Site 2. Four non-native fish species collected at Site 1 were not collected at Site 2. Because native fish (bluehead sucker, speckled dace, and roundtail chub) were more common at Site 2 (upstream from the reservoir) and less common at Site 1 it seems likely that there is greater competition from non-native fish downstream from the reservoir. Although non-native fish species were encountered upstream from the reservoir it is likely that most inhabit the reservoir and less frequently move upstream to compete for habitat in the stream, especially the species such as bluegill and black crappie which are more typically found in lentic habitats. The smallmouth bass upstream of the reservoir were generally in the juvenile size class with very few in the young of the year size class (Fig 5). This would seem to indicate that the fish either move upstream from the reservoir or there is small reproducing population in the stream itself. The lack of large smallmouth bass would indicate that the stream population is low. Table 2. Total number and relative abundance of fish captured at Site 1 on 12 September, 1995 and at Site 2 on 13 September, 1995 from Elkhead Creek. Species Site 1 Site 2 N umber Relative Number Relative Abundance Al)undancc C_V1DIS* 13 -/o 4 10J°,o CATCOM Auw1 82 16.1% Ei6 15.9% CATLAT* 7 1.4% 2.2% COTBAI* 31 6.1% 6 1.4% GILROB* 16 3.9 LEPMAC 1 0.2% MICDOL cy Can- 153 30.0% 39 9.4% PIMPRO 5 1.0% 33 8.0% POMNIG 10 2.0% RICBAL 26 5.1 , "1 79 19.1% RHYOSC* ? 96 18.8% 121 29.3% SEMATR 81 15.9% - -? SUCKERX 5 1.0% Grand Total 510 100.0% 414 100.0% * Native Species