For over a century, fish hatcheries across the world have produced salmonids to supply fisheries, mitigate habitat loss and boost depleted stocks. A newly published review of scientific literature examining the impacts of these programs on wild (i.e., naturally produced) salmonids shows that over 80 percent of global, peer-reviewed research on the topic has found that hatchery fish have adverse effects on wild salmonid populations in freshwater and marine environments.