Sockeye salmon, which mysteriously vanished last year prompting a government inquiry, are expected to return to Canada's Fraser River this month in numbers not seen since 1913, officials said Wednesday.
"Test fishing catches of sockeye have continued to be strong in the marine approach routes over the past several days," the Pacific Salmon Commission said in a report.
"Current run size assessments suggest that the total Fraser sockeye return this season is slightly over 25,000,000 fish, which is the largest return since 1913."
The commission is responsible for shared salmon stocks on the Pacific Coast of Canada and the United States. Its latest forecast is double previous estimates for this season.
Last year, Canada's Department of Fisheries and Oceans had projected that between six and 10 million sockeye salmon would return to the Fraser river in a peak August run.
Only a fraction showed up and where the others went remains a mystery.
A record number of salmon smolts were born in the Fraser in 2005 and migrated to the Pacific Ocean. Experts had expected many of them to return by last year to spawn.
Officials and ecologists speculated the salmon could have been affected by warmer ocean temperatures, fewer food sources, or more prey.
Alternately, they might have contracted sea lice or an infection from area fish farms, or the fisheries department's complex forecasts may have been flawed.
A judicial inquiry set up in November 2009 to investigate has not yet concluded its work.
"Everybody is abuzz about the great return of the Fraser sockeye," Fisheries Minister Gail Shea told the daily Globe and Mail. But "we're welcoming this with cautious optimism," she added.
Explore further: Pesticides significantly reduce biodiversity in aquatic environments