FREDERICTON, New Brunswick – Wild Atlantic salmon populations in eastern Canada and the United States have dropped to historic lows, according to an Atlantic Salmon Federation report released Thursday.

Bill Taylor, president of the New Brunswick-based federation, said that in the absence of strong domestic and international government action, the wild Atlantic salmon would eventually vanish from its North American ranges.

“Since 1974, we have gone from more than 1.5 million salmon to fewer than 500,000 today,” Taylor said during a news conference releasing the latest population figures. “This year, scientists project an especially disturbing decline in returns of large salmon to their native spawning rivers.”

The rates of return are used to gauge the health of the population.

It is especially bad news for New Brunswick, where some of Canada’s most storied salmon rivers have built thriving tourism industries on sport fishing and the allure of the wild salmon.

Suggested causes of the decline include changing ocean conditions, acid rain, industrial pollutants, poaching and illegal bycatch, habitat degradation and poorly regulated salmon aquaculture practices.

“Our most pressing concern is the salmon populations from rivers in the Bay of Fundy, the Gulf of Maine, and on Nova Scotia’s Atlantic coast,” he said.

“The inner Bay of Fundy’s wild Atlantic salmon population is severely endangered. Incredible as it may seem, there are now fewer than 200 fish in the inner bay’s 32 rivers, down from 40,000 just 20 years ago,” Taylor said.

He said populations returning to rivers in the outer Bay of Fundy are also under severe stress.

The report in Canada mirrors one released in January in Maine, which says rehabilitation efforts are urgently needed if Maine’s once-abundant Atlantic salmon are to be replenished.

The National Academies’ National Research Council called for such measures as removal of dams, a reduced reliance on hatcheries and the potential use of limestone to counteract stream acidification.

Michael Clegg, chairman of the committee that wrote the report, said Atlantic salmon were close to extinction in Maine.

In New Brunswick, Taylor said that even though there have been good rates of return in the past to New Brunswick rivers like the Miramichi and the Restigouche, as well as in some Newfoundland and Labrador rivers and Cape Breton’s Margaree, the outlook for this year is not good.

He said scientists are projecting a return of fewer than 100,000 of the larger, egg-bearing females to North American rivers this year.

“This number isn’t even half the total number needed to meet minimum conservation targets,” Taylor said.