Salmon returning to the rivers of Vancouver Island to spawn have always had a long and perilous migration route. But in the past 10 years their time away has become deadlier than ever, with populations dropping precipitously.
Salmon returning to the rivers of Vancouver Island to spawn have always had a long and perilous migration route. But in the past 10 years their time away has become deadlier than ever, with populations dropping precipitously.
This decline has led to the restriction or closure of culturally and economically important fisheries, and is threatening the survival of species that depend on salmon, including the iconic and endangered southern resident killer whales.
While many factors have contributed to the dwindling numbers of salmon—historic overfishing, warming ocean temperatures, reduced river levels, hatchery competition, freshwater habitat destruction, and disease—it’s difficult to pin down the most significant causes.
“If we don’t know why the returning numbers of Pacific salmon are so low, we can’t take effective measures to protect them and the many species that depend on them,” says Francis Juanes, a University of Victoria fisheries ecologist and Liber Ero Chair in Fisheries Research.
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Image via University of Victoria.
