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I I I I I I I I I I I I I I I I I I I for the electrofishing Jon boat (Table 8) were for flannelmouth sucker (501.6), carp (308.1), red shiner (277.4), fathead minnow (183.9) and bluehead sucker (182.3). Differences in catch rates between the two types of electrofishing boats can be related to two factors: 1) catch rates were reflective of actual differences in species composition between the upper Dolores River (above the confluence of the San Miguel River) where the canoe was primarily used and the lower Dolores River (below the confluence of the San Miguel) where the Jon boat was the primary electrofishing craft and; 2) higher catch rates of smaller species with the Jon boat may be reflective of slight differences in effectiveness between the jon boat and canoe for electrofishing. Effectiveness of electrofishing from either boat was influenced by conductivity, flow, turbidity and channel morphology. High conductivities associated with particular areas within the study reach probably had the greatest influence. The Paradox Valley subreach (Subreach IV) was particularly affected by high conductivities associated with saline groundwater inflow. Electrofishing in this reach was generally ineffective. Conductivities in the other subreaches were within an allowable range for effective electrofishing. High turbidity associated with summer storms also affected electro fishing efficiency, primarily during Trip 2, when extremely high turbidities were encountered during approximately 50% of the days. This influenced electrofishing success by impairing the netter's ability to see fish and possibly reducing fish activity. High turbidity was generally not a problem during the spring and fall sampling trips. 4.2.2 Gill and Trammel Netting Catch rates for experimental gill nets (Table 9), trammel nets (Table 10) and floating trammel nets (Table 11) are presented separately as number of fish per 100 linear feet of net per 100 hours. The highest catch rates for experimental gill nets, which were used most frequently, were for flannelmouth sucker (81.4), roundtail chub (17.9) and bluehead sucker (9.8). Trammel nets, both sinking and floating also produced relatively high catch rates for flannelmouth sucker at 34.1 and 97.6, respectively. High catch rates for carp and channel catfish in trammel nets, are probably more indicative of the effectiveness of the gear type at capturing spiney-rayed species than actual differences in densities when compared to catch rates with experimental gill nets. Above the confluence of the San Miguel River, low flows associated with reduced releases from McPhee Dam., did not supply an adequate volume of water in the river channel to effectively utilize nets for sampling. This situation was particularly evident during Trip 1 when releases from McPhee were reduced to 20 cfs and remained at that level throughout the sampling trip. Under these conditions nets could be used in very few locations where deep pools or runs could be found. In some reaches where the channel was wide and shallow, netting was impractical and not attempted. Below the confluence of the San Miguel River higher water volume, made gill and trammel netting more effective. Floating debris associated with summer storms affected netting efforts during Trip 2. Additionally, high turbidity associated with these summer storms probably decreased fish activity and therefore catch rates. 4.2.3 Seining The seining information presented in Table 12 represents catch rates from a total of 10 habitat types (backwaters, trickle-fed-backwaters, eddies, embayments, shorelines, sidechannels, runs, riffles, pools and isolated pools). These catch rates are presented by habitat type in Tables 13-22. When viewed across all habitats, catch rates for seining were highest for red shiner (164.7 fish/l00 meters), fathead 9