Abernathy Creek Steelhead: Population Genetics and Reproductive Success at a Conservation Hatchery with Wild Broodstock Integration

Integrated hatchery programs typically strive to prevent genetic divergence between hatchery-origin (HOR) and natural-origin (NOR) components of the population.  The goal of this project was to determine the natural reproductive success and mean relative fitness of HOR and NOR steelhead (Oncorhynchus mykiss) in Abernathy Creek, WA.  The Abernathy Fish Technology Center (AFTC) developed an integrated steelhead broodstock in 1999 starting with pre-smolt NOR juveniles collected from throughout Abernathy Creek and then rearing the broodstock to maturity in the hatchery.  From 2003 thru the present, NOR juveniles have been captured and compared with samples collected from the progeny of AFTC’s broodstock to assess genetic changes associated with captive rearing of steelhead.  With the return of the first adults produced from the original 1999 broodstock, AFTC has had a policy of maintaining ~25% NOR integration in the broodstock, with the remaining returning NOR steelhead being released back into the stream to reproduce naturally. In addition, from 2005 thru the present, both returning adult HOR and NOR steelhead have been captured and genetic samples taken.  The resulting dataset has allowed us to assess the relative reproductive success and genetic characteristics of the annual broodstock compared to fish produced in the stream.