A question of survival.

Fish hatcheries are a lousy substitute for Mother Nature.

In recent decades, fish biologists increasingly have cautioned against overreliance on hatcheries in efforts to help endangered fish species recover. They have argued that there are critical distinctions between hatchery and wild fish.

But the scientific evidence has been slow in coming. For example, the notions that hatchery fish produce offspring that are less able to survive in the wild, and that inferior genetic traits of hatchery fish can weaken wild runs through interbreeding, have not been conclusively proven.

A new study by Oregon State University researchers provides an important piece of the evidentiary puzzle. While its findings focus exclusively on steelhead, it's reasonable to believe they extend to salmon and other species as well.

The study, published Friday in the journal Science, is based on 15 years of genetic samples collected from both wild and hatchery steelhead that passed over a dam on the Hood River. A genetic analysis of samples from more than 15,000 fish found that in just one generation after a wild brood stock goes into a hatchery, the chances that their offspring will successfully spawn in the wild are reduced by 15 percent. For subsequent generations, the reproductive success falls off by an astonishing rate of 37 percent.

The findings mirror the claims of many fish biologists and conservationists who say wild fish that survive nature's fearsome culling in their early stages are best equipped to survive and reproduce in the wild. In contrast, hatchery fish that are protected from the time they are eggs and are not subject to the rigors of natural selection are far less likely to survive and reproduce in the wild.

By now it should be clear to everyone - including the Bush administration, which has failed to fulfill its responsibility to protect threatened and endangered salmon species in the Columbia River Basin - that continued reliance on hatcheries cannot ensure the recovery of struggling fish species.

OSU zoology Professor Michael Blouin puts it this way: "The argument that hatchery fish and wild fish are functionally equivalent is basically dead. If the idea is just to produce for harvest, hatcheries are really good at that. If the goal is to help wild populations, then you are in a completely different ball game."

Yet many still cling to the myth that hatcheries allow Americans to continue to dam and pollute their rivers, overdevelop and overgraze their watersheds and clear-cut their forests and still have abundant, healthy wild fish runs.

Despite recent court rulings to the contrary and mounting scientific evidence, property rights advocates and development interests in the Northwest continue their fight to get many salmon and steelhead runs off the endangered species list by forcing federal agencies to count hatchery fish along with wild fish.

While the OSU study should not be regarded as definitive and more research is certainly needed, it should help put to rest the idea that hatchery and wild fish can be regarded as interchangeable parts of the same machine.

Hatcheries can play a significant role in fisheries management, and OSU researchers rightly caution that their findings should not be used as an indictment of all hatchery programs.

But hatcheries can never compensate for the wholesale degradation of habitats - or the continued existence of dams that represent the single greatest threat to the survival of salmon in the Columbia Basin.

There are simply no shortcuts when it comes to saving wild fish.