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<br />(SPSS 1996). <br /> <br />RESULTS <br /> <br />Each sample site, except site 4, was visited 17 times during <br />the two-year study; site 4 was sampled 15 times. A total of 1132 <br />habitats was sampled, of which 929 were occupied by fish. We <br />collected a total of 55,590 specimens of 13 species in these <br />habitats (Table 2). Three nonnative species, ~. lutrensis, E. ~2 <br />promelas, and Gambusia affinis were the first, second, and forth <br />most abundant taxa, accounting for 77.0% of the total catch. <br />Native R. osculus, C. latipinnis, and ~. discobolus were the <br />third, fifth, and sixth most abundant (respectively) and <br />accounted for 17.8% of the catch. Density of the five most <br />common species and age-classes of each varied similarly each year <br />(Fig. 2). Total density was generally highest in the late ~ L <br />summer, although there was a spike in total density in the spring <br />of 1994. Adult density was the most stable while larvae only <br />occurred during the summer and autumn. <br />Habitat available and habitat sampled differed among sample <br />-, L. <br />sites (Table 3). Site 4 had the greatest mean current velocity <br />and depth, while site 2 was the shallowest with the lowest mean <br />current velocity. In general, our sampling reflected spatial <br />differences in habitat available among sites. However, at all <br />sites we tended to sample habitats that were significantly <br />shallower and had lower current velocities than was available <br />_\ I.- <br />(Table 4). This was primarily because efficient sampling was <br /> <br />10 <br />