Counter to what many top state officials – including Gov. Angus King – have long contended, Maine’s wild Atlantic salmon are genetically unique, and, therefore, worthy of protection under the federal Endangered Species Act, the National Academy of Sciences said in a report released Monday.

King and members of the state’s congressional delegation in 2000 criticized a federal decision to list the fish in eight Maine rivers as endangered. U.S. Sens. Olympia Snowe and Susan Collins asked the esteemed National Academy of Sciences to review the situation.

The panel of prominent scientists, which twice visited Maine last year, issued an interim report on salmon genetics Monday. A more complete report on the status of Maine’s Atlantic salmon, which will focus on the causes of the fish’s decline, is due by the end of the year. The genetics review portion is not expected to change.

“It’s not interim in the sense that this is a tentative conclusion,” said David Policansky, the director of the salmon review project for the academy. “We are not going to change our minds.”

While stopping short of saying the NAS study supports the salmon listing, Policansky said, the report reaffirms the conclusion reached by the two federal agencies that listed the fish as endangered that Maine salmon are genetically unique. “This is consistent with the analysis they did to conclude these fish are distinct,” he said Monday.

A spokesman for Sen. Snowe stressed the report was only preliminary and that it did not address the most important question: Whether the federal government was using the best scheme available to protect the salmon.

“This is not the final determination as to whether an ESA listing is the best way to preserve the fish,” said Dave Lackey. He said Snowe still believes the state plan devised in 1997 would do a better job of protecting salmon. The federal agencies rejected the state plan in favor of the ESA listing because they said it was lacking in many areas, especially regarding controls on the aquaculture industry and water withdrawals from the salmon rivers.

Lackey said the report was heartening in that it found Atlantic salmon are very resilient and have survived more than a century of stocking and other potentially harmful events.

Gov. King was reserving comment on the study Monday until he had a chance to review it with scientists in Maine, including University of Maine zoology professor Irv Kornfield, said spokesman Tony Sprague. Kornfield is the scientist the state has relied most heavily upon in its challenge to the validity of the listing decision.

Borrowing a phrase from Kornfield, Gov. King often has likened the fish to “mongrels.” This is because salmon from other states and Canada have been put into the eight rivers by the millions over the last century. The fish in question are simply salmon that are in Maine rather than a unique strain of Maine salmon, King told the panel in June.

At that same meeting, King said he would accept the NAS findings. At that time he said, “If the National Academy of Sciences says it is a [distinct population segment], I’ve got to step up and say, ‘You’re right.'”

In Monday’s report, the NAS found that even with decades of stocking of foreign fish, Maine’s salmon have remained unique.

“Despite [the stocking], the evidence is surprisingly strong that wild salmon in Maine are genetically distinct from Canadian salmon,” the NAS panel wrote.

Getting directly to the governor’s point, the committee wrote the “data are persuasive … from which we conclude that the natural salmon spawning in Maine’s [Distinct Population Segment]-designated rivers are ‘Maine salmon,’ not just ‘salmon in Maine.”

This is in line with analyses done by the National Marine Fisheries Service and the U.S. Fish and Wildlife Service that determined salmon in eight Maine rivers were a distinct population segment, a subset of a species, and therefore qualified for protection under the Endangered Species Act. Because so few wild salmon have been documented in the rivers, five of which are in Washington County, the agencies proposed in 1999 to list the fish as endangered.

Since then a battle has ensued, with the state going to court to challenge the listing decision. The National Academy review was expected to quell the fighting.

Asked whether the state would continue to pursue the lawsuit despite the NAS findings, Sprague said it was too early to answer that question.

Federal fisheries officials and conservationists said they were pleased by the report and hoped it would encourage the state to drop its legal challenge.

“Hopefully, [the genetics debate] can be laid to rest and we can focus on recovery,” said Mary Colligan of the National Marine Fisheries Service.

She said her agency hoped the report would provide final guidance as to what recovery efforts would be the most successful in the future.

Jeff Reardon of Trout Unlimited said his group hoped the report would help “put the genetics war behind us so that we can move ahead with what’s best for restoring the salmon population.”

Sebastian Belle, executive director of the Maine Aquaculture Association, however, said his group was “absolutely” committed to pursuing the lawsuit filed by the state and supported by a coalition of aquaculture, blueberry and timber companies. His group is part of a coalition that contributed $60,000 toward the suit.

That’s because the NAS study failed to answer the question of whether the genetic differences found in Maine fish could likely be caused by the federal government itself, Belle said.

That’s possible because the federal fisheries agencies about 15 years ago adopted a river-specific stocking program whereby fish are handpicked to be mated to produce offspring for each of the eight rivers. This is causing the genetic make-up of these fish to change over time and to become different from those in neighboring Canada, Belle said.