The Role of a Production Hatchery in the Maintancence of the Genetic Identity of an Otherwise Diluted Sub-Population in Siletz River Steelhead

While conservation-oriented hatcheries may explicitly set out to preserve threatened native stocks, production hatcheries may also serve that role deliberately or inadvertently. In this study, we examined steelhead sampled in the Siletz River. We found that the production hatchery in the system maintains a stock of steelhead that genetically resemble those with a run-timing unique to the system. We also provide evidence that naturally rearing steelhead of this sort have otherwise been genetically diluted due, likely due to past management decisions. However, we also found that the intrinsic genetic diversity of the hatchery stock is considerably lower than steelhead from other parts of the system. The hatchery operation, therefore, has both maintained a separate group of fish with a unique life-history but failed to maintain high levels genetic diversity. This is particularly interesting in comparisons to other systems where hatchery programs have either become homogenized with the local populations without losing genetic diversity or even maintained increased levels of genetic diversity relative to endangered native stocks. Properly managed, it is possible that hatcheries could continue to maintain the genetic diversity of local populations when those populations are diminished due to anthropogenic or environmental stress.