The lake of [Jay] Hall’s memory is dead, its salmon all but vanished in the past decade – a collapse so swift that fisheries biologists have likened it to driving off a cliff. For a brief few decades, those biologists had turned this Great Lake into a Pacific chinook factory, taking a wildly popular sport fish from faraway ocean waters and setting it loose to gorge upon the swarms of invasive alewives that had decimated native fish species.