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<br />METHODS <br /> <br />Sampling protocol- Sampling occurred between April and July during runoff when flow <br />was sufficient to navigate the river. The Hayden Reach was sampled only in 1999 and <br />critical habitat was sampled from 1999 through 2002. In critical habitat reaches, there <br />were four sampling occasions each year and each occasion required 10 to 12 <br />continuous days to sample all three reaches. In years when flows declined rapidly, <br />some sections of river within each reach were not navigable by electrofishing boat by <br />the fourth sampling occasion and were not sampled. In 1999, only backwaters were <br />sampled; in later years, both shorelines and backwaters were sampled. Backwaters <br />included flooded ephemeral, tributary washes and irrigation return channels. <br />Shorelines included all habitats associated with water's edge and were sampled by boat <br />electrofishing, starting at the most upstream location and progressively moving <br />downstream about 0.6 to 3.0 m from shore. One electrofishing boat was used in 2000 <br />and two electrofishing boats were used in subsequent years. When two boats were <br />used, both shorelines were sampled simultaneously. <br /> <br />Small backwaters were sampled by electrofishing boat and the sampled included <br />with riverine, electrofishing effort. If a backwater was large enough, it was blocked to <br />prevent escapement of fishes during sampling with a fine-mesh net set at the mouth <br />and a trammel net set about 0.3 m inside the block net. The fine-mesh block net <br />allowed us to work the trammel net between sampling passes without fish escaping. In <br />1999, backwaters interiors were seined (block-and-seine) for adults and some <br /> <br />10 <br />