- WASHINGTON (Reuters) - Salmon and shrimp farming does not protect the world's
lessening fish supply, as once thought, but actually reduces it because
of feeding requirements and environmental damage, researchers said Thursday.
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- Scientists had thought fish farming,
or aquaculture, could provide a valuable resource management tool and a
steady food supply. But a new report indicates the booming shrimp and salmon
industries actually damage the delicate balance of the seas.
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- "(The report) challenges the very
common assumption that fish farming produces more fish for the world to
eat," said Rebecca Goldburg, a biologist for the Environmental Defense
Fund who worked on a special report published in the journal Science.
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- She and a team of international researchers,
including experts in aquaculture, ecology, and resource economics and policy,
said the rapid growth of shrimp and salmon farming endangered the environment.
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- "The increasingly large scale of
these industries, combined with other human activities, now places substantial
demands on ocean ecosystems, which in turn result in the demise of fisheries
and biological diversity," they wrote.
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- They said global aquaculture production
more than doubled in weight and value between 1986 and 1996 to account
for more than one-quarter of all fish consumed by humans.
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- But farmed shrimp and salmon are fed
other fish in the form of fish meal and fish oil. And it is an inefficient
process.
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- For instance, said Jane Lubchenco, a
marine ecologist at Oregon State University who worked on the study, it
takes 3 pounds of wild-caught fish to produce enough protein for 1 pound
of salmon.
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- Million of tons of fish are already caught
on the open seas to supply the fish farms, and these numbers will only
increase, the experts say.
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- "So it's a losing proposition if
what you are trying to do is decrease the pressure on wild-caught fish,"
Lubchenco said.
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- The discharge of waste and pesticides
from farm ponds into the open ocean is another problem, because it depletes
natural fisheries by destroying nursery areas supporting wild fish and
other marine species, Lubchenco said.
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- Shrimp and salmon are farmed in coastal
areas where building ponds can damage the natural environment. Shrimp farms
are often built in fragile mangrove forests -- a practice that, combined
with coastal development, has already caused 50 percent of mangrove habitat
to disappear, Lubchenco said.
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- Mangrove forests are important sources
of the tiny particles of plant material that form the base of the food
chain. "What you are doing is depleting the ocean of natural food
for other fishes, sea birds and marine mammals," she said.
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- And, she said, much of the world's shrimp
production comes from Latin American and Asian countries that do not all
strictly regulate the industry.
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- The researchers pointed out that some
types of fish farming were sustainable and could offer viable alternatives
to wild-caught fish and act as a valuable food source.
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- "Good" farms produce carp,
oysters and mussels, they said.
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- But there is a pressing need to consider
the serious problems created in the growing $8 billion shrimp and salmon
industries, the experts said.
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- "We are not damning all aquaculture,"
Lubchenco said. "Some types of fish farming will be an essential component
of food for the future. We are saying these two are growing explosively,
and these are ones where we need lots of improvements."
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- By Michael Kahn, Reuters News Service
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