The Bush administration announced here on Friday a plan to consider hatchery salmon, which are bred in concrete pens, when deciding whether wild stream-bred salmon deserve protection under the Endangered Species Act.

In explaining the new policy, which caused a regional uproar when it was leaked last month, the regional administrator for the National Marine Fisheries Service said that hatchery fish will be used to "contribute to the rebuilding" of endangered wild runs of salmon.

But Bob Lohn emphasized that hatchery fish will not, by themselves, become "the solution." Hatchery salmon are pumped into regional rivers by the hundreds of millions each year.

"We are not saying that all these fish are considered equally," Lohn said. "That is not the heart of this policy."

He said hatchery fish will be used to "contribute to the rebuilding" of endangered wild runs of salmon. "It has been done," he said, "and it appears to work."

Many fish biologists say there is no convincing scientific evidence that hatcheries can be used to help recover wild, self-sustaining populations of salmon.

Environmental groups have criticized the hatchery plan as a gift to timber, home-building and power-generating interests. Those groups have complained for decades about the high cost of protecting and restoring vast stretches of habitat for wild salmon.

In apparent response to that criticism, Lohn said the Bush administration will not flood local rivers with hatchery fish as a way of escaping legal responsibility under the Endangered Species Act. "Abundance alone, large numbers of fish, is not a determination of what we call viability," he said.

To reassure Northwest residents that the new policy will not cause any sudden change in the 15-year federal effort to save salmon, federal officials announced here that the government will continue to protect 26 species of fish now listed as endangered or threatened. For good measure, it added one new salmon species to the list.

While welcoming this news, a number of fish biologists remained dubious about the motives behind the federal plan. They said the new policy could be used any time the government wanted to bring hatchery fish into the survival equation and take genetically similar wild fish off the endangered list.

Robert T. Paine, an ecologist at the University of Washington and one of six scientists asked earlier by the federal government to comment on its salmon-recovery program, told reporters he had a "Machiavellian perception of what is going on."

Paine said that the Bush administration, by making hatchery fish a required part of any legal calculations about the health of wild salmon, will "set into action an increased series of lawsuits" by business interests.

The government will be pleased to lose these lawsuits and to take various salmon species off the endangered list, Paine said, thereby saving some of the $700 million a year it spends on salmon recovery.

Paine said that, by letting the courts do the dirty work, the Bush administration will be "off the hook" for any responsibility for extinction of wild fish.

Asked about that criticism, Lohn dismissed it as "conspiracy" thinking.