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FEASIBILITY OF DEVELOPING AND MAINTAINING A SPORT FISHERY IN THE SALT RIVER PROJECT CANALS Table 4. Number of fish species collected (species richness) by year, from 5 electrofishing sites along the Arizona Canal, October 1992 through July 1994. Year n Site 1 Site 2 Site 3 Site 5 Site 7 Year Total x 1992 3 11 11 12 8 8 11 10.0 1993 12 17 12 15 13 11 17 13.6 1994 7 15 10 12 6 4 15 9.4 Overall Total 18 13 15 13 12 x 14.3 11.0 13.0 9.0 7.7 Sixty percent of the fish sampled during our monthly electrofishing surveys were taken from Sites 1 and 3; 25% (n = 3,336) from Site 1 and 35% (n = 4,714) from Site 3. We collected the fewest fish (n = 1,264, or 9.5% of the total count) from Site 7. Electrofishing catch-per-unit-effort (CPUE) was summarized by site (Table 5) and by season (Table 6) for 8 species: Sonora and desert suckers, red shiners, threadfin shad, white amurs, largemouth bass, channel catfish, and rainbow trout. Sonora and desert suckers were the most abundant fish collected during our electrofishing surveys. These fish were found at all sites, but were most abundant at Site 3 based on total number caught and CPUE. Native fish, including roundtail chubs, accounted for about 58% (n = 7,784) of all fish collected. We collected a total 43 roundtail chubs, or 0.3% of the total sample. Forage fish (threadfin shad and red shiners) were taken from all our collection sites and comprised approximately 36% (n = 4,853) of our total electrofishing sample. The total number caught and CPUE for threadfin shad increased moving downstream (Site 7 to Site 1). Red shiners were also sampled at all sites, but CPUE was highest at Site 2. Collectively, forage fish were the second most abundant group of fish collected during our study. White amurs were found at each site, but these fish were most abundant at the downstream end of the Arizona Canal. White amurs accounted for about 2% (n = 251) of the total electrofishing sample. Since white amurs have a tendency of moving downstream towards the Skunk Creek Drain (Site 1), SRP periodically moves many of these fish to upstream canal sections. Salt River Project relocation efforts influence the abundance of white amurs across sites. Game fish (largemouth bass, resident channel catfish, yellow bass, and resident rainbow trout) represented 3% (n = 369) of the total electrofishing sample. Largemouth bass, resident channel catfish, and yellow bass were collected from all 5 fish collection sites along the Arizona Canal. Resident rainbow trout were collected from all sites except Site 3. Largemouth bass and channel catfish had the highest CPUE at Site 3. Overall, game fish numbers were very low when compared to the native suckers and forage fish. Condition Factors. Most resident fish in the Arizona Canal were in good physiological condition based on overall mean condition factors (mean K; Table 7). All species sampled had mean K values > 1.00, except threadfin shad, roundtail chub, channel catfish, and rainbow trout, which had mean K values > 0.80. Due to missing TL and weight data, the number of fish used to calculate mean K factors differed from the total number of fish sampled (Table 3). Most threadfin shad (79.5%), red shiners (99.9%), and all western mosquitofish (Gambusia affinis) were below our weight criteria (i.e., < 10 g) for calculating K factors. Size and Age Structure. Mean lengths were calculated for all species collected (Table 8). Seasonal length frequency distributions were created for largemouth bass, threadfin shad, red shiners, Sonora suckers, desert suckers, and white amurs. Additionally, overall length frequency B. R. WRIGHT AND J A. SORENSEN 1995 ARIZONA GAME & FISH DEPARTMENT, TECH REP. 18 21