Can Farmed and Wild Salmon Coexist?

When the cod industry off Canada's eastern shore collapsed in 1992, industrial fisheries could no longer ignore biologists' warnings that the ocean would not sustain unlimited exploitation of its fish stocks. But a nearly 5-fold increase in global marine catch over four decades had already taken its toll, placing the persistence of scores of the sea's giant predators—long-lived species that take several years to reach sexual maturity, like bluefin tuna, halibut, and sharks—in serious jeopardy. Many organizations, including the World Bank, saw aquaculture (raising fish in ponds or open net pens in bays) as the best way to relieve pressure on depleted wild populations while meeting consumer demand. Aquaculture now accounts for over 30% of the world's fish market and about half of store-bought salmon.