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During 1994 and 1996 zooplankton was more abundant for a fourto six week period, whereas in 1995, zooplankton remained over 20/1 zooplankters for nearly two months. In 1995 and 1996, zooplankton numbers peaked after the wetland was disconnected (396 m3/s) from the river. Chapter Two: Fish Abundance and Composition Methods Gear used to capture fish differed each year of the study in an effort to increase efficiency of sampling. Differences in gear used prevented annual comparison of catch per unit effort. One consistency through the study was an attempt to sample fish at one week intervals after the wetland was connected to the river, and two week intervals after the wetland was separated from the river. Fish collections in 1994 began 6 June and ended 5 October; in 1995 sampling began 25 May and ended 31 August; and 1996 samples were collected between 15 May and 9 July. In 1994 seine collections did not begin until 29 June because of the difficulty in finding seineable locations. Effort also was different among years. During 1994 each weekly effort consisted of one experimental (13 mm x 25 mm x 38 mm bar mesh) gillnet 46 m long and between 9 and 12 seine (4 m long and 3.2 mm mesh) hauls per week (see Appendices 1,2, and 3 for sampling effort per year). On and after 28 July, 1994, a second 55 m long, 38 mm bar mesh gill net was added to the sampling effort. Gillnets were set over night and both gillnet and shoreline seine sampling locations were selected arbitrarily. In 1995 and 1996 specific sampling designs were followed. A grid series was overlaid on a map of Old Charley Wash and sampling sites were selected randomly. Sampling effort in 1995 consisted of three fyke nets (.9 m tall and 1.5 wide horizontal first hoop dimension, and 13 mm mesh) and four 23 m experimental (13 mm x 19 mm x 25 mm bar mesh and 152 mm, 178 mm, and 203 mm panels) trammel net sets, four circular seine collections, four cylindrical minnow traps (3.2 mm mesh), and three light traps per week. Cylindrical minnow traps were .4 m long and .2 m in diameter. Circular seine hauls consisted of placing a 22.9 m bag seine (3.2 mm mesh) in a circle, pulling out the vegetation from the circle, constricting the seine, and retrieving the fish from the bag of the seine. This procedure was modeled after Bayley and Herendeen (1994). Fyke net and minnow trap sampling locations were selected randomly only from shoreline grids and trammel nets and light traps were selected randomly only from open water grids. Concern for mortality on adult razorback sucker caused us to set trammel nets for only two hours in the morning. Nets were checked midway through each set to remove any endangered fishes that might be caught. Following capture, fish were identified to species, and length (Total length in mm) and weight (to the nearest gr) recorded. In 1996, fish were sampled with smaller mesh fyke nets (6 mm mesh), trammel nets (same as used in 1995), tall (.9 m) clover-shaped minnow traps (3 mm mesh), short (.5 m) clover-shaped minnow traps (3 mm mesh), and light traps. Clover-shaped minnow traps consisted of three circular cylinders, 0.48 m in diameter, that were connected with an aperture of 3.2 mm. During 1996, sampling sites were determined the same way as in 1995 (i.e. randomly selected grids) with fyke nets, short clover-shaped minnow traps and light traps set in only randomly selected shoreline grids. Trammel nets and tall clover-shaped minnow traps were set only in randomly selected off-shore grids. Each weekly sampling effort consisted of eight fyke nets, eight tall clover-shaped minnow traps and eight short clover-shaped minnow trap sets, four 17