Wednesday, November 26, 2003

Nature fish farming news focus (by Kendall Powell):
Global aquaculture is on the rise, growing more than 5% per year over the past decade. That might sound like good news for the world's food supply, but there's a hidden cost behind some of the farmed fish on supermarket shelves. Many, including the popular salmon, trout and cod, are fed on wild fish. Lots of wild fish. Today, about 11 million tonnes of fish � 12% of the total haul from seas and rivers � are caught each year just to feed farmed fish. It takes 2 to 5 kg of wild fish just to produce 1 kg of a farmed fish such as salmon.

This will soon pose a huge problem. Farmed fish are fed on a diet that leans heavily on fish oil and fishmeal � a protein-rich powder of ground-up, cheap fish such as sardines, anchovies and eels � as a source of vital proteins and nutrients. A simple calculation shows that the current haul of fish oil and fishmeal will soon be outstripped by the needs of global aquaculture. If the number of fish farmed continues to grow at its current rate, and if the supply of oil and meal stays the same � as it has for the past decade � then demand will outstrip supply of oil by 2010 (ref. 4). If those projections are extended, fishmeal looks set to face the same problem by 2050.

Over the past few decades, researchers have begun to think that one way to make aquaculture more sustainable is to change the diets of some of our farmed fish � to turn carnivores into vegetarians. It's a solution that carries its own challenges, but in the face of declining wild stocks and a booming aquaculture industry, many fish farmers and conservationists agree that if we are to continue farming carnivorous fish, this is the way to go.

[paragraphs out of order]


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