HELD BACK: Pacific salmon raised in hatcheries, such as the Big Qualicum Hatchery in British Columbia, are less likely than wild-born fish to survive ocean life.DAVID WILLIS, SALMON ENHANCEMENT PROGRAM
When captive-bred Pacific salmon leave their hatcheries to swim free in the ocean, they soon take on the look of their wild counterparts, with the color of their sides changing from red to silver, the better to mesh with their new saltwater digs. But in important, less visible ways, the fish never shake the legacy of their domestic upbringing: They are less likely than wild-born salmon to survive in rivers and the ocean, and if they live long enough to reproduce, they produce fewer offspring.
Just what’s wrong with these hatchery-reared fish? With wild stocks on the decline and aquaculturists stepping in to try and bolster Pacific salmon populations, answering this question—and, if possible, increasing the fitness of hatchery-raised fish—has gained importance.
Some researchers suggest ...