In both British Columbia and Washington state, fishery managers, provincial and state legislators, the sports fishing lobby, and even the whale watching industry have advocated for increased production of hatchery chinook to “save” the critically endangered southern resident killer whales.
While seemingly logical at first blush, this idea lacks a biological or ecological basis. Further, pursuing this strategy could undermine recovery efforts for wild chinook and the needed rebuilding of runs throughout their historic range, their size and age structure, and the run-timing that the whales evolved with. There are several reasons for this.
Chinook are managed under the Pacific Salmon Treaty. If the coastal abundance of migrating chinook salmon increased due to hatcheries, the catch of migrating chinook in fisheries of southeast Alaska, northern BC and Vancouver Island’s west coast would automatically increase to reflect that level of abundance. Unless fisheries management under the Pacific Salmon Treaty is addressed, little of the increased production from hatcheries would be reflected in the Salish Sea.
Southern resident killer whales evolved to target large and old chinook salmon that returned to rivers from early spring to fall and in some places, year round. Hatcheries have failed to protect or restore the old ages, big sizes, range of migration times and diversity of wild chinook salmon. For southern residents to recover, the age structure and run timing of wild chinook runs, along with abundance, need to be restored. This is not the objective of hatcheries.
While the effect of hatcheries is worsened by fishing pressure and climate change, new science suggests that the billions of hatchery salmon released into the North Pacific every year are overgrazing the commons. There simply isn’t enough food to go around and chinook may be bigger losers in this game than say, pink salmon. Whatever the mechanism, the evidence shows that the more hatchery fish there are, the less likely that wild chinook can recover, and could just as easily result in fewer, smaller chinook overall.
Lastly, there is growing evidence that hatcheries are part of the reason chinook have failed to recover. Hatchery rearing domesticates salmon, selecting for genes suited to the hatchery environment but that are maladaptive in the wild. This results in reduced fitness of hatchery salmon once released. In the wild, ecological interactions also occur that adversely affect wild salmon. On the spawning grounds, hatchery fish interbreed with wild fish reducing the fitness and genetic diversity of wild salmon.
The problems with hatcheries have long been identified in the U.S. by the Hatchery Scientific Review Group. In the U.S. these targets are blatantly ignored as the proportion of hatchery origin chinook on wild salmon spawning grounds in most Washington state rivers exceed “biologically acceptable” levels.
Increased abundance of hatchery (or wild) chinook would automatically trigger higher catches in fisheries under the Pacific Salmon Treaty, increase pressure from sports and commercial fishers for fishing opportunities, and perpetuate the unsustainable harvest of wild chinook that migrate with hatchery stocks, the problem that has perpetuated the decline of early-run endangered Fraser chinook.
Any consideration to increase the production of hatchery chinook in order to help southern resident survival and recovery is dependent first on reconfiguring fisheries, i.e. eliminating coastal mixed-stock chinook fisheries, and providing the necessary foraging refuges for whales. Unless and until this is done, there should be no increase (and probably some reductions) in the numbers of hatchery chinook produced.
The rush to focus on a conjectural quick fix in the form of increased hatchery production is symptomatic of the failure of current management to address past mismanagement of chinook populations coast-wide. The push for more hatcheries springs from the misguided hope that a technological response will somehow solve a complex ecological problem.
Reliance on this unsuccessful industrial tool to address the complex ecological issues facing whales and wild chinook is destined to fail both species. Government managers responsible for chinook salmon and these killer whales have too long ignored the significant harvest issues that are responsible for a large part of the decline and failure for wild chinook to rebuild. Increasing hatchery production will never ameliorate this fundamental mismanagement of wild salmon nor will it rescue our priceless killer whales from the precipice of extinction.
Misty MacDuffee is a biologist with the Raincoast Conservation Foundation, Nick Gayeski is the senior fisheries scientist at the Wild Fish Conservancy and Chris Genovali is the executive director of the Raincoast Conservation Foundation.