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<br />Past studies have collected tens of thousands of fish from the Colorado River inflow, however, <br />sampling may have been biased toward either small or large fish (Valdez and Cowdell 1994a and <br />1994b, Muth and Wick 1996 and 1997). Seining, larvalli~~:ht traps, and electrofishing were the <br />primary methods used. Seining was effective for small fi~h not large fish. Unfortunately, steep <br />muddy banks, deep channels, and brush or debris make seir,ing difficult. Larger fish are more <br />susceptible to electrofishing, but turbidity decreases the likelihood of seeing and netting the fish. <br />Because of these limitations, it was speculated that juvenile natives may have avoided detection <br />and capture. <br /> <br />We used standard sampling methods to target all life stages, especially juvenile fish. These <br />included custom built minnow traps, hoop nets, and 1.2-cm and 3.7-cm trammel nets. Many of <br />the techniques have been developed for razorback sucker culturing programs in the Lower Basin <br />(Tom Burke, Bureau of Reclamation [BOR] and Chuck Minckley, Fish and Wildlife Service <br />[FWS] personal communique). To our knowledge, these methods had not been widely used in <br />the Upper Basin. <br /> <br />Glen Canyon National Recreation Area recently developed an Adaptive Management Program to <br />examine management issues for natural resources within the park's boundaries. A major <br />program component is to better understand the influence that reservoir operation has on native <br />and nonnative fish communities both upstream and downstream of Glen Canyon Dam. This <br />study attempts to address some of those key issues. <br /> <br />METHODS <br /> <br />Sampling Schedule <br /> <br />Sampling started on Monday and was completed by Thursday of each trip. Five trips were <br />conducted on the San Juan Arm both in 1999 and 2000 (Table 1). The Colorado River inflow <br />was examined once in the spring of 1999 and twice in 2000. The schedule follows: <br /> <br />1999 <br /> <br />Table 1. Lake Powell Inflow sampling schedule <br /> <br />2000 <br /> <br />Colorado River April 12th <br />San Juan River* May 10th, June 14th, July 12th, August 16th, October 4th <br /> <br />Colorado River April3rd, May 15th <br />San Juan River* May P1, June 5th, June 26th, July 17th, August 2Pt <br /> <br />* included both the inflow and Spencer's Camp (control) sites <br /> <br />2 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />,I <br />I <br />I <br />, <br />I <br />I <br />I <br />I <br />il <br />I <br />I <br />I <br />I <br />