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1 <br />1 <br /> <br />' TABLE 2: Fish population parameters for Rito Seco creek, Costilla County, Colorado, 16-17 <br />August 1988. <br />Estimated ±9596 Mean Mean <br />Number Density Confidence Biomass Length Weight <br />Species Captured (#/ha) Interval (kg/ha) (cm) (gm) <br />' Site 1 <br /> Brown trout 8 246 0 17.8 17.5 72.4 <br /> Brook trout 10 318 87 17.3 15.9 63.4 <br /> Cutthroat trout 4 123 92 2.5 12.0 20.3 <br />' TOTAL 22 687 39.5 <br /> Site 2 <br />' Brown [rout 13 871 • 16.7 9.6 19.1 <br /> Brook trout 56 4029 517 85.5 11.5 21.2 <br />' TOTAL 69 4,900 102.2 <br /> Site 3 <br /> Brown trout 54 2479 590 56.8 10.2 22.9 <br />' Brook trout 12 474 30 29.4 15.3 62.0 <br /> Cutthroat trout 1 40 0 4.0 21.0 99.0 <br /> Fathead minnow 6 296 387 0.8 5.6 2.8 <br />' TOTAL 6 3 <br />2 <br /> 7 , <br />89 91.2 <br />' • Confidence interval not calculated due to positive slope. <br />1 <br />Benthic Invertebrates <br />' A total of 49 different taxa were collected from the three sites on Rito Seco creek, with 18 <br />' [axa found at all three sites (Table 3). Immature forms of aquatic insect species daminated the <br />populations at all three sites. Non-insect species (e.g. worms and flatworms) were important <br />only at Site 1. The five insect orders (Ephemerop[era, Plecoptera, Trichoptera, Diptera and <br />' Coleoptera) typically found in Rocky Mountain streams were present at all sites. There were <br />no significant differences between sites in terms of density, biomass or number of taxa (ANOVA <br />' p > 0.24). <br />Densities of benthic invertebrates at all three sites ranged from 1,747 - 5,717 organisms/mZ <br />' (Table 3). Biomass ranged from 5.7 to 7.8 grams/mz (Table 4). These values are typical of those <br />found in similar streams throughout Colorado. For example, Cor five sites at similar altitudes <br />' 6 <br />1 <br />