Most of us probably agree that the wild salmon fisheries of the Pacific Northwest are well managed and sustainable. However, Alaska, Canada, Oregon and Washington all release Pacific salmon (Oncorhynchus spp.) into the wild as part of their management programs (Japan and Russia are also in the hatchery salmon game) and questions about these “hatchery fish” are growing.
What are the ecological and genetic effects of hatchery salmon on wild salmon populations? That’s the question that the “How Wild is Wild” panel at this year’s Sea Web Seafood Summit was tasked with discussing.
Moderated by Sam Wilding, Seafood Watch Senior Analyst/Reviewer, Monterey Bay Aquarium, the panel consisted of Jeff Regnart (Director of the Division of Commercial Fisheries, Alaska Department of Fish and Game), Greg Ruggerone (Salmon Scientist, Natural Resources Consultants, Inc.) Stuart Ellis (Fishery Scientist, Columbia River Inter-Tribal Fish Commission) Megan Atcheson (Fisheries Assessment Manager , Marine Stewardship Council) and Randy Ericksen (Fisheries Science Director, Ocean Outcomes).
One of the concerns voiced by the panel was genetic diversity; since parents are selected artificially, a small number of parents produces a large number of offspring. Additionally there may be potential adaptation to the hatchery environment, meaning the hatchery raised fish might not be as genetically fit for the natural environment.
There are also concerns about hatchery fish interacting with wild fish. Are these “hatchery strays” competing with wild fish for habitat and for feed? Can interbreeding impact the robustness of the wild population? Does reproductive success decline with increased hatchery strays?
The panel also stressed that the carrying capacity of ecosystem must be enough to support both wild and farmed (with wild fish the priority).
Understanding the carrying capacity of the North Pacific is a complicated process.
Hatchery scientists do focus on ways to eliminate or reduce the potential impacts mentioned above. They locate hatcheries away from wild populations, work to maintain genetic diversity and use local brood stocks, permit hatcheries at lower initial capacities and promote selective fisheries for marked hatchery fish.
All the panelist agreed that no matter how robust your hatchery program is, the most important factor in sustainable wild salmon populations is maintaining healthy habitats. Development, logging, mining, dams, pollution – all of these issues are a very real threat to all wild fisheries. Without healthy habitats you’re not going to have a productive fishery of any kind.
Questions from the audience came in regarding concerns over where hatcheries source their feed and how they monitor chemical and antibiotic use in hatcheries. Should these issues be looked at with the same scrutiny that’s used when ranking salmon farmer for sustainability?
Both the Marine Stewardship Council and Seafood Watch are working on implementing different sets of standards that take into account issues unique to wild fisheries supplemented by hatcheries.