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Despite Efforts by Researchers, Maine Salmon Face Extinction

By Beth Daley
THE BOSTON GLOBE


EAST ORLAND, MAINE

Five years after the federal government declared Atlantic salmon endangered in Maine, the fish continue to vanish despite a rescue effort that so far has cost taxpayers at least $20 million, and scientists are fearful that they are witnessing an extinction unfold.

Restocking of Maine rivers with native salmon bred in a hatchery, the centerpiece of the recovery program, has been an exercise in frustration. Hardly any of the fish have returned to their home streams to spawn after swimming out to the ocean; today there are only about 80 returning adult salmon in the eight rivers where their population is endangered. A decade ago, there were more than twice as many salmon in those rivers.

Scientists are racing to figure out how they might still save the salmon before the fish, and continued public support for the government program, disappear.

“These rivers are in trauma mode, the IV is in,” said Joseph Zydlewski, research scientist with the Maine Cooperative Fish and Wildlife Unit for the U.S. Geological Survey.

Zydlewski and some other scientists are calling for more aggressive, though potentially risky, actions to rescue the native salmon, such as introducing different types of salmon into the rivers.

But other scientists and advocates are urging caution, saying that one wrong move could wipe out the population for good.

Maine’s rivers once teemed with the leaping silvery sport fish that became so popular one was ceremoniously delivered to the U.S. president each year. But water pollution and acid rain, dams, overfishing, habitat loss, and a host of maddening unknowns are believed to have slashed their numbers over the last century.

All Atlantic salmon in Maine are doing poorly, but scientists are particularly worried about the population in the eight rivers because their gene pool is believed to be the least diluted and their survival offers the best chance to restore Maine’s historic wild salmon runs, with fish leaping upstream to return to their ancestral spawning grounds.

Last month, federal officials released a long-awaited $34 million recovery plan that broadly spells out 14 major threats to the endangered salmon population and steps required to increase their numbers, including keeping the hatchery effort going, more research on water quality, and ensuring the endangered population maintains enough genetic diversity to avoid inbreeding.

Yet some scientists and advocates say current restoration efforts go far enough.

“Now is the time to feel out ideas and experiment, before you get to the point where there is no choice,” Zydlewski said. He wants to place Penobscot River salmon, which are not endangered, into the Dennys River, one of the rivers where salmon are endangered, to better understand why Penobscot salmon return from the ocean in greater numbers. Zydlewski figures a head-to-head comparison will help determine whether something is wrong with the Dennys river or with the endangered salmon breeding stock. The other seven waterways are the East Machias, Machias, Pleasant, Narraguagus, Ducktrap, and Sheepscot rivers and Cove Brook.