Make Yourself at Home: A Structure and Behavioral Study on Wild Broodstock Steelhead

One of the biggest hurdles for a juvenile steelhead (Oncorhynchus mykiss) is migrating downstream from freshwater spawning grounds to the ocean.  Add one or more dams and reservoirs to successfully navigate through and survival rates decrease further.  In our attempt to successfully recover a wild winter run of O. mykiss to the North Santiam River in western Oregon, wild broodstock was reared from the South Santiam River for over one year.  At the Oregon Hatchery Research Center (OHRC), the fish were reared for nine months on two treatments: conventional tank and a tank with a scalable complex structure that was easy for hatchery staff to implement and clean.  Both groups were reared at densities below conservation hatchery standards and fed low-lipid experimental diets.  Fish quality was assessed using morphometric and growth rate analyses. Behavioral assessments, including predator-avoidance and foraging behavior patterns, were used to evaluate treatment effects.  The goal of this project is to improve on current hatchery practices to produce a wild “surrogate” fish for tagging studies when a wild run is not large enough to provide experimental animals.