The world is dependent on fish farms. In fact, one out of every four fish consumed worldwide has been raised on a farm. The irony is that fish farming, or aquaculture, while helping to feed a growing human population, often comes at a surprising cost to wild fish populations.
"A lot of countries could use more protein, and aquaculture is a good way to get there," indicates Rosamond Naylor, an economist at the Stanford (Calif.) Institute for International Studies. The problem, she points out, is that farmed salmon, shrimp, and other carnivorous species often take more out of the oceans than they keep in. That's because certain farmed fish are given processed feed made from wild catches of herring, mackerel, sardine, and other varieties. Naylor estimates that nearly two pounds of wild fish are required for every pound of farmed fish raised on processed meal.
While, on balance, aquaculture still adds to the world's supply of seafood, fish farming often influences wild populations--displacing natural breeding habitats, spreading disease, and polluting the oceans in many ways that haven't been measured.
Aquaculture needn't be so disruptive, she maintains. "There are now identifiable ways to improve shrimp aquaculture," such as reducing food input and developing closed-water systems that prevent waste and parasites from escaping. Farming more-vegetarian fish and shellfish--such as carp and mussels--is one way to produce needed fish protein for people without depleting ocean populations. Moreover, shellfish farming purifies the water by filtering out algae and waste.
Naylor believes that aquaculture, when done correctly, can provide more benefit than harm and that scientists and economists can offer critical improvements to a rapidly expanding industry. Commercial fish farms should take advantage of the new research on fish nutrition, she says. In the meantime, those at the fish market should watch what they eat. "People should be aware that they are not doing the environment a favor at all by eating farmed salmon."
COPYRIGHT 2001 Society for the Advancement of Education
COPYRIGHT 2001 Gale Group
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