As decades of recovery efforts have demonstrated, protecting wild salmon runs throughout the Northwest is a costly and convoluted endeavor. Despite the purest of intentions, attempts to mitigate the impact of dams throughout the Columbia Basin have often proven to be ineffective or even counterproductive.
While annual runs of some 15 million wild salmon once flooded the Columbia River, a labyrinth of man-made barriers has helped whittle that return to a small fraction of the previous number. Despite the development of a hatchery system to raise salmon and return them to the wild, would-be solutions all too often have been specious in their effectiveness.
All of which brings into sharp relief a new study from Oregon State University and the Oregon Department of Fish and Wildlife, with the findings adding a new variable to discussions about how to improve salmon survival rates and preserve one of the Northwest’s cultural landmarks. The study identified crucial differences between wild salmon and hatchery salmon, and co-author Michael Blouin, a professor of biology at Oregon State, told the Corvallis Gazette-Times: “I think it lays to rest the question of whether wild fish and hatchery fish can be genetically different. It’s very clear that they’re adapting in ways that make them unfit in the wild and that are detectable at the genetic level.”
The study found differences in the activity of 723 genes between wild steelhead and first-generation hatchery steelhead. Many differences appear to represent evolutionary changes brought about by the crowded conditions of the hatchery, and Blouin said: “What appears to be happening is that you have two very different environments, and fish can adapt to one or the other but not both. It’s stunningly fast.” Blouin adds that the findings should lead to changes in how hatcheries are designed, providing salmon with conditions that more closely represent those found in the wild and, ideally, improving survival rates.