Harrison River sockeye may hold key to species’ survival
By Robert Freeman - Chilliwack Progress, August 12, 2010
Something out in the ocean may ultimately lie behind the decline of sockeye salmon returning to the Fraser River, says SFU fish biologist John Reynolds.
But something in the Harrison River species of sockeye may hold the key to the future of the “iconic” fish that has come to symbolize B.C. and the mighty Fraser River, he said.
Reynolds is chair of a salmon research lab at SFU and sits on the advisory panel to the Cohen Commission looking into the decline of Fraser River sockeye.
Last year, when only 1.5 million sockeye returned to the Fraser, instead of the 10.5 million forecast, the Harrison River salmon run more than doubled.
“They just came storming back,” Reynolds told a Rotary Club meeting last Friday. “We don’t understand why.”
But scientists note the Harrison fish is “different” than most salmon species, with a two-year-life cycle rather than the usual four, and it goes straight to sea instead of spending a year maturing in freshwater lakes.
“Something about the lifestyle works better,” Reynolds said.
Harrison sockeye may also take a different route to the sea, going up the west side of Vancouver Island, rather than the east side like the others.
Fish farms crowd those eastern shores, but Reynolds doubts sea lice caused the collapse of the sockeye returns in 2009. He also discounts over-fishing as the cause of the decline, which began about 15 years ago, along with an ominous drop in productivity.
But these declines were not factored in to the run-size estimates made by federal fisheries and the Pacific Salmon Commission.
But Reynolds said forecasting fish runs, like forecasting the weather, is an imperfect science given all the variables involved.
“It’s a fool’s game,” he said, and nobody is doing a better job of it than the DFO and PSC.
He said there are “hints” the cause of the decline is related to “human-induced global climate change,” which has warmed the ocean and the river creating new challenges for survival of the young sockeye.
Some Fraser River sockeye, which have survived six million years of changing conditions, will ultimately vanish, he suggested, but others will adapt and thrive.
“Sockeye are not going extinct in the future, but some filtering of the stocks will take place,” he said.
