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Air Spawning Summer Steelhead ( Oncorhynchus mykiss ) For Kelt Reconditioning and River Release - Dworshak National Fish Hatchery Thomas E. Tighe ( tom_tighe@fws.gov , Jeremy M. Sommer ( jsommer@nezperce.org ) Dworshak National Fish Hatchery , 276 Dworshak Complex Drive, Orofino, ID 83544.
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Air Spawning Summer Steelhead (Oncorhynchus mykiss) For Kelt Reconditioning and River Release - Dworshak National Fish Hatchery Thomas E. Tighe (tom_tighe@fws.gov, Jeremy M. Sommer (jsommer@nezperce.org) Dworshak National Fish Hatchery, 276 Dworshak Complex Drive, Orofino, ID 83544 • Populations of wild steelhead have declined from historical levels in the Columbia and Snake rivers. In an effort to increase adult steelhead returns to Idaho’s Clearwater River , a collaborative effort between the U.S. Fish and Wildlife, Nez Perce Tribal Fisheries, Columbia River Inter-Tribal Fish Commission and the University of Idaho was launched to catch adult Clearwater River Steelhead, air spawn the females, recondition them in the Kelt Program at Dworshak N.F.H. and ultimately release them back into the river to spawn again. Air spawning has proven to be an efficient tool for the Dworshak production staff, allowing for a clean, efficient alternative spawning technique to “kill spawning”, allowing more live fish to be released into the Clearwater River for anglers to catch. • Specific Air-Spawning Materials Used: • AQUI-SE®-anesthetic • 16-20 gauge, 0.75-1.5 inch needles • Needle disinfectant-95% ETOH • No-Foam® • Poly Aqua® • Air-line trigger with Luer-Lock syringe mount • Results: • 2013, Egg Fecundity dropped from an average of 6,411 eggs/female in the kill spawned fish, to 5,682 eggs/female in the air spawned fish. • Eyed egg survival in the air spawned females was 90%, verses 91.8% in the kill spawned fish, showing very little difference between the two techniques. • The production crew can air spawn fish as efficiently as they can kill spawn. • The spawning floor is significantly cleaner with air spawning , allowing for less potential disease transmission. • Equipment Set-Up & Preparation: • Needle air pressure set at 2-5 PSI • AQUI-SE®- 150-200ml/1000 liters water • Point 4 oxygen stones in anesthetic bath and recovery tank set at 1-1.5 liter/min.