Wednesday, December 21, 2011
New Study Tracks Rapid Hatchery Domestication
A new study by Oregon State researchers is shedding some light on hatchery domestication, and calling into question the practice of using hatcheries as a means of recovering wild populations. While it is not the first study to document reduced fitness in hatchery fish and it certainly will not be the last, it does shed important light on the process by which hatcheries reduce the fitness of wild stocks. The authors reconstructed a multi-generational pedigree using genetic tools - basically a family tree - for a wild broodstock hatchery program in the Hood River. They found that the offspring of wild fish brought into captivity had significantly lower survival in the hatchery environment, however domestication occured rapidly and the offspring of first generation hatchery fish survived almost twice as well in the hatchery as offspring of wild fish.
More importantly the authors found that traits which confer success in the hatchery lead to poor performance in the wild. With so many hatchery programs around the region shifting their production to wild brood, these results highlight the fact that regardless of which broodstock a hatchery selects, domestication and a loss of fitness in hatchery populations is unavoidable. The hatchery environment itself imposes a profoundly different set of conditions, selecting for traits which are harmful in the wild. If managers are serious about recovery of wild salmon we need to start asking hard questions about just how necessary hatcheries are in that process. The long held dogma among hatchery proponents is that wild populations had been depressed to a point of no return and without hatchery intervention there could be no recovery. However, the more we learn the more that notion appears at odds with reality.
Check out this article in the Oregonian on the study:
A copy of the research paper here:
Christie et al - Genetic adaptation to captivity can occur in a single generation