Flawed fish.

Byline: The Register-Guard

Fish biologists have long warned against overreliance on hatcheries in efforts to recover endangered fish species, arguing that there are critical distinctions between hatchery and wild salmon.

But it's taken decades to accumulate scientific evidence supporting biologists' contention that hatchery fish produce offspring that are less able to survive in the wild and have inferior genetic traits that can weaken wild runs through interbreeding.

A new study of steelhead in the Hood River provides the most definitive evidence to date. Conducted by Oregon State University and federal researchers, it confirms that hatchery fish lose the instincts and other traits that allow wild fish to survive and thrive. For example, the study found that typical hatchery steelhead produced 60 percent to 90 percent fewer offspring that live long enough to become wild steelhead.

That's hardly surprising. Wild salmon that survive nature's fearsome culling in their early stages are those best equipped to survive the rest of their arduous sojourn to the ocean and back again. By contrast, hatchery fish are protected from the time they are eggs and are not subject to the rigors of what Charles Darwin called natural selection. When released, they're killed by predators and other natural hazards at a far greater rate than their wild cousins.

As author and scientist David Montgomery noted in his book "King of Fish," "Releasing hatchery fish into a stream is like dropping suburban teenagers into the middle of the Congo and asking them to walk out of the jungle to the coast."

The study found, however, that hatcheries using an emerging prac- tice called "supplementation" have more promising results.

The strategy involves taking eggs from local wild fish, hatching and raising the young in captivity and then turning them loose before they become too softened by their captivity. Researchers found that the few Northwest hatcheries using this approach produce salmon that yield healthy offspring at the same or better rate than wild fish.

That promising finding should prompt more hatcheries to shift to the supplementation approach. However, no one should be deceived into believing the already-disproved myth that hatcheries can allow Americans to dam and pollute their rivers, overdevelop and overgraze their watersheds and clear-cut their forests and still have abundant, healthy salmon runs.

The study offers reason to hope that hatcheries can play an important role in salmon recovery. But nearly a century and a half of experience with hatcheries has proven they cannot compensate for the massive destruction of habitats.

The study also should help thwart property rights activists, who, with the full blessing of the Bush administration, have sought to dismantle Endangered Species Act protections by arguing that hatchery fish should be counted along with wild fish in determining whether a population is in danger of extinction. The new study should forever put to rest the idea that hatchery and wild salmon can be regarded as interchangeable parts of the same machine.

Hatcheries can never replace healthy salmon habitat. There are no shortcuts when it comes to saving the remnants of the Northwest's shattered salmon populations.