Increased farming of large predators, such as salmon and tuna, has led to overfishing of prey fish, including anchovies and herring, which are commonly used as fishmeal. It generally takes at least three kilograms of feed to produce one kilogram of salmon. The shrinking of the numbers of prey species threatens the entire food chain, putting further stress on large predator stocks. "Even as we depend more on farmed fish, a growing scarcity of fish-feed may jeopardize future expansion of the industry," said Brian Halweil, Worldwatch senior researcher and co-project director of the Institute's Nourishing the Planet project, a two-year evaluation of agricultural innovations.
This could also negatively affect the economies of developing countries, home to the nearly 60 percent of the world's fishers that are classified as small-scale commercial or subsistence fishers. In Africa, an estimated 100 million people depend on fish from inland sources, such as lakes and rivers, for income as well as protein and much-needed micronutrients like vitamin A, calcium, iron, and zinc. But coastal fisheries across West Africa have declined by up to 50 percent in the last 30 years due to significant pressure from large industrial fleets.
Fisheries also provide important ecosystem services, such as storing and recycling nutrients and absorbing pollutants. "Fish farmers and the food industry will need to make ecological restoration as much a goal as meeting the growing demand for seafood," said Danielle Nierenberg, Nourishing the Planet co-project director.
Negotiations are currently under way at the World Trade Organization to establish new rules on fisheries subsidies that would eliminate unfair and environmentally destructive policies while ensuring a level playing-field and abundant resources for all fishers. But top-down fisheries management has had limited success in the past. In contrast, fisheries co-managed by local authorities and fishers themselves have emerged as a promising solution to replenishing depleting fish stocks.
In 2007, a group of Gambian women oyster harvesters formed the TRY Women's Oyster Harvesting Association. They have collectively agreed to close one tributary in their oyster territories for an entire year and to shorten their harvest season by two months. These practices may seem difficult in the short run, but they pay off over time, securing incomes and nutrition in their communities.
