Salmon raised in man-made hatcheries can harm wild salmon through competition for food and habitat, a finding with worldwide implications, researchers say. More than 20 studies by university scientists and government fishery researchers in Alaska, British Columbia, Washington, Oregon, California, Russia and Japan provide mounting evidence fast-growing hatchery fish compete with wild fish for food and habitat in the ocean as well as in the rivers where they return to spawn, the Oregon-based Wild Salmon Center reported Monday. \"The genetic effects of mixing hatchery fish with wild populations have been well-documented,\" researcher David Noakes of Oregon State University said. \"But until now the ecological effects were largely hypothetical. Now we know the problems are real and warrant more attention from fisheries managers.\" The findings raise questions about whether the ocean can supply enough food to support future increases in hatchery fish while still sustaining the productivity of wild salmon, experts said. \"This isn\'t just an isolated issue,\" Pete Rand, a biologist at the Wild Salmon Center, said. \"What we\'re seeing here in example after example is growing scientific evidence that hatchery fish can actually edge out wild populations.\" Losing wild fish would mean losing the genetic diversity that has allowed salmon to survive for centuries, researchers said, while hatchery fish lack the diversity that provides insurance against fisheries collapses. \"There is no substitute for wild salmon. They must be our first priority,\" Guido Rahr, president of the Wild Salmon Center, said. \"Wild salmon are an important part of local culture and a cornerstone of economic health for fishing communities.\"