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Final Report Minnow Traps Unbaited minnow traps were used to sample small fish in shoreline habitats. Commercial Gee minnow traps were used that were 44.5 cm (17.5 in) long, 22.9 cm (9 in) diameter, and constructed of galvanized wire and steel. Funneled openings were located at each end of the trap. Traps were placed on the bottom or suspended in the water column depending on conditions. Traps were also set in pods of five as sample repetitions for habitat types. Each trap was tethered to a secure anchor point and discretely flagged for easy relocation. Traps were checked at intervals of no longer than 12 hr to minimize stress and mortality to fish, and to minimi7e escapement by fish. Seines Seines were used to sample assemblages of small fish in relatively shallow habitats (up to about 1.5 m in depth). Three sizes of seines were used, including 9.1 m x 1.2 m x 0.6-cm (30 ft x 4 ft x 0.25-in), 9.1 m x 1.5 m x 0.6-cm (30 ft x 5 ft x 0.25-in), and 3.0 m x 0.9 m x 0.3-cm (10 ft x 3 ft x 0.125-in) (length x height x square mesh). The float line was constructed ofO.8-cm (0.32-in) braided polypropy- lene with hard foam floats at 45-cm (l8-in) intervals. The bottom line was made of braided polypropylene line with lead sinkers at IS-cm (6- in) intervals. Length and width of each seine haul were measured and three water depths were recorded at each sample site; one at the deepest point of the haul, one midway between the deepest point and the nearest shore, and one between the deepest point and distal end of the seine haul. Length and width of the habitat sampled were also recorded. Electrofishina Electrofishing was used to sample fishes along shorelines and to capture adult humpback chub for implanting radio transmitters. Each electrofishing effort was conducted within a distinct geomorphic shoreline type (i.e., debris fan, bedrock cliff, cobble bar, sand bar, talus, vegetation) to evaluate habitat use and reduce variability in comparing catch rates between habitats and reaches, as well as between flow levels and over time. Electrofishing was conducted along shallow shorelines and partitioned by day, night, and crepuscular periods. Study Design . 2-9 Electrofishing was conducted from an Achilles SU- 16 research boat capable of ascending small and mediwn-sized rapids for increased access to sample areas (See Box 2-la.). Each boat was designed to meet Occupational Safety and Health Administration (OSHA) safety standards with specialized features such as pressure-sensitive safety switches, insulated railing, separate line- channeling for circuits and lights, and complete system groWlding. Rubber gloves, rubber boots, and fiberglass-lined dip nets were provided for netters and boat handlers. The system was powered by a S,OOO-W Yamaha industrial grade generator (Model YG-500-D) or a Honda 5,000-W generator (Model EB 5,000X) and routed through a Mark XX Complex Pulse System (CPS) developed by Coffelt Manufacturing (Flagstaff, AZ). Stainless steel spheres were used as electrodes with the anode (positive electrode) suspended on a cable from a fiberglass boom projecting from the bow, and the cathode (negative electrode) was suspended from a cable from the stem. Anode and cathode were exchanged every 45-60 min,of electrofishing to allow for cleaning of the cathode surface by reversing the electroplating process. During 1990-91, CPS output ranged from 15 to 20 A and 300 to 350 V, as recommended by Coffelt Manufacturing for electrofishing in the Colorado River below Glen Canyon Dam (N. Sharber, Coffelt Manufacturing, pers. comm.). In 1992, output was reduced to a range of 8 to lOA and 200 to 250 V after bruise marks were observed on trout under the higher settings. The electrofishing system and the fish captured were continually monitored to minimize injury to fish as reported by Sharber and Carothers (1988), Sharber et al. (1994), and McMichael (1993).. Analina Angling has been used as an effective method for capturing humpback chub in the Upper Colorado River Basin, in Black Rocks and Westwater Canyon (Valdez et al. 1982) and in Yampa Canyon (Tyus and Karp 1989). Cheese balls, commercial salmon eggs, stink bait, grasshoppers, Monnon crickets (Tyus and Minckley 1988), and artificial flies have been used with varying success. Angling was not used extensively in this Grand Canyon study because of the time necessary to catch this species by angling, and because other sampling gears were