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<br />, <br /> <br />Habitat Management Plan <br /> <br />Rotary Screw Trap Installation and Operation in the Skokomish, Dewatto, and <br />Tahuya Rivers <br /> <br />Key component of a Steelhead Supplementation Study implemented by NOAA Fisheries, <br />along with collaborators: Washington Department ofFish and Wildlife, US Fish and <br />Wildlife Service, Skokomish Tribe, Long Live the Kings, and the Hood Canal Salmon <br />Enhancement Group <br /> <br />Introduction: Salmon and steelhead hatcheries in the Pacific Northwest primarily <br />provide fish for harvest. In the past decade, hatcheries have developed new programs <br />(termed 'supplementation programs') with different goals: to aid in the conservation and <br />rebuilding of depleted natural populations. Results of a small-scale supplementation <br />project in the Hamma Hamma River suggest that the strategy of collecting natural-origin <br />embryos and rearing them for release at two different life-history stages (smolt and adult) <br />has substantially increased the number of redds constructed in the Hamma Hamma River. <br />This approach contrasts markedly with hatchery programs commonly implemented in the <br />past, which released large numbers of out-of-basin fish in Pacific NW rivers, with many <br />negative consequences. Though the strategy of supplementation has proved promising in <br />theory and in small-scale or laboratory situations, a large experimental approach has not <br />been taken. NOAA Fisheries has undertaken a collaborative project which will look at <br />the large-scale effects of supplementation, as measured through the comparison of four <br />treatment (Hamma Hamma, Skokomish, Duckabush, and Dewatto) with three control <br />(Dosewallips, Tahuya, and Big Beef Creek) streams located throughout the Hood Canal <br />region (Figure 1). One key component to evaluating the benefits and impacts of <br />supplementation is to measure the abundance of juvenile production within each of these <br />streams before, during, and after treatment. <br /> <br />Project Description: Within the context of this project, we propose that a rotary screw <br />trap be installed in the Skokomish, Dewatto, Tahuya, and Duckabush Rivers (see Figure <br />1). A similar trap is already in operation on the Hamma Hamma River, and plans are <br />underway to install a trap on the Dosewallips as well, though timing for this action is not <br />certain. The trap is prefabricated and will be trailered into each site. In some cases, a <br />small crane may be required to relocate the trap from the trailer to the river site. Twenty- <br />two foot (Skokomish) and 17 foot 4 inch (Dewatto and Tahuya) aluminum pontoons will <br />hold the trap on the surface of the water, and an attached cone (diameter = 8 ft for <br />Skokomish, 5 ft for Dewatto and Tahuya) uses the hydraulic energy of the current to <br />revolve on a central shaft (Figure 2). The cone is situated halfway beneath the surface of <br />the water, and guides migrating juvenile salmonids into a flow-through trap box that is <br />located downstream of the cone (Figure 3). In this way, a certain percentage offish are <br />enumerated and access is gained so as to obtain biological and genetic samples. After <br />target fish (Steelhead and Cutthroat) are separated from non-target fish (Chinook, Chum <br />and Coho), they will be lightly anesthetized and sampled. Cutthroat will be used for trap <br />efficiency tests in the event that large enough numbers of steelhead are not encountered. <br />