On the Elk River, this problem was especially acute. As adults, these fish sometimes cruise past or never reach their home hatchery and instead mate with wild-born fish, distorting wild gene pools that have been finely tuned by natural selection.
Many hatchery fish are released in unfamiliar streams or in other conditions in which they don’t readily imprint. Read: The surprise hiding in the DNA of pet fishīut hatchery-raised salmon can take straying too far. And as climate change shrinks Alaska glaciers, salmon have begun to trickle into newly exposed streams and lakes.
Helens erupted in 1980, for example, steelhead trout, a salmon relative, couldn’t survive the ash-choked Toutle River but bred in nearby watersheds. National Oceanic and Atmospheric Administration, “it’s an important alternative strategy” that helps populations survive disaster and expand their range.Īfter Washington’s Mount St. “From an evolutionary standpoint,” says Andy Dittman, a Seattle-based biologist at the U.S. A small portion naturally strays into other streams. The alluring aroma of ale is a bid to solve a sticky conservation conundrum: How do you get hatchery-reared salmon to come home?Īlthough the majority of salmon return to their birthplace to spawn, sometimes the fish slip up. Several years from now, however, if scientists at the Oregon Hatchery Research Center have their way, some chinook salmon will be chasing a very different scent: the rich, beery bouquet of brewer’s yeast. No one knows precisely what scents young salmon memorize, but it’s probably some combination of mineral and biological signals, such as distinctive metals. Guided by the odors they imprint on in their youth, most adult salmon famously return to spawn in the stream where they were born. Of all the traits that make salmon extraordinary migrants-their leaping prowess, their tolerance of both fresh and salt water, their attunement to the Earth’s magnetic fields-the most impressive might be their sense of smell. This article was originally published by Hakai Magazine.
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