Such is the curse of salmon’s shifting baseline: coming to accept as normal what is in fact a diminished state of affairs.

Usually baselines are set according to present circumstances. Sometimes, though, it’s the historical record against which the present moment is measured—and when that history is revised, our understanding of the present, of where the baseline ought to be, undergoes a radical shift.

That’s the case with Canada’s Skeena River, the nation’s second-largest salmon watershed, which until recently teemed with wild sockeye salmon. The salmon—who are vital to the food security of Indigenous peoples and wild animals, the prosperity of commercial fishers, and the transport of ecosystem-sustaining nutrients throughout the watershed—are generally thought to have declined moderately since the mid-20th century.