Hatchery salmon stocks have long been used to “mitigate” the damage to wild salmon stocks caused by habitat loss, dams, water quality issues and others.
A growing body of evidence suggests they’re not simply mitigating the damage to wild stocks, but actually causing it:
The ocean’s a pretty big place, right? Maybe not big enough for wild salmon and hatchery salmon to share, according to new research.
A special issue in the journal Environmental Biology of Fishes looks at how hatcheries are affecting wild fish populations. Research for the issue came from scientists around the Pacific Ocean – from Japan to California.
One of the major findings: hatchery fish may be outcompeting wild fish for food in the Bering Sea.
That area is a feeding hot-spot for chum salmon – where fish that came from hatcheries mix and mingle with wild fish.
With millions more hatchery salmon arriving at the feeding grounds, there’s not enough to go around and the researchers say that contributed to a significant drop in the wild chum population.
With California’s wild salmon and steelhead populations in decline, hatcheries remain a reality, though better, more thoughtful approaches are needed — especially those emphasizing the restoration of wild fish populations (via habitat restoration, rewatering, water quality fixes, etc).
— Protect & Restore, CalTrout