A framework for the use of conservation hatcheries to support wild Pacific salmon recovery in Canada

Hatcheries have long been used to produce Pacific salmon ( Oncorhynchus spp.), and in recent years, they have been used to assist the recovery of populations that have declined and become imperiled. For populations where the conservation of biodiversity is a primary goal, we used guidance from Canada's Wild Salmon Policy, and recent scientific advice, to develop a framework for the use of hatchery supplementation in the recovery of wild salmon in Canada to manage the tradeoff between the increase in abundance that a hatchery program can provide, with the risks to wild salmon from supplementation. We use a simple deterministic model to show that hatchery supplementation can play a role in boosting abundance during the early phases of recovery of wild salmon populations, but if natural production does not increase, the population may become dominated by hatchery-origin spawners and may be contrary to biodiversity goals. We conclude that in certain circumstances conservation hatchery programs can be an appropriate tool for the recovery of wild salmon populations, but uncertainty about long-term risks to wild populations requires a cautious approach. Careful planning and ongoing monitoring and program adjustment are needed to ensure that adverse impacts are minimized.