- CAMBRIDGE, Mass. (AP) - Foreign marine life invading waters where they
are not normally found has escalated into a multibillion dollar nuisance
as fishermen continue to dump exotic species, bacteria and viruses from
their boats, biologists warned Tuesday.
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- The sea life is often found lurking in
cargo holds or in ballast water pumped in to stabilize ships during their
voyage and then pumped out when they reach their destination.
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- Once the invaders take hold, they can
devour native species, alter food chains and change whole ecosystems, biologists
say.
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- "There are a lot of global marine
hitchhikers and now is the time to take action," said Secretary of
the Interior Bruce Babbitt, who spoke Tuesday at the first international
Marine Bioinvasions Conference at the Massachusetts Institute of Technology.
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- Bioinvasion costs government and industry
$123 billion a year to control on land and at sea, according to a study
released at a meeting of the American Association for the Advancement of
Science, Babbitt said.
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- In the San Francisco Bay area - where
there are more than 250 known exotic invaders - one of the most voracious
predators has been the Asian clam introduced in the 1980s.
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- The mud-dwelling clams feed by filtering
out food particles in the water column.
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- "The clams have been filtering out
so much of the water that we haven't seen annual blooms of phytoplankton
since the 1980s," said Andy Cohen, a marine biologist for the San
Francisco Estuary Institute in Richmond, Calif.
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- That means animals who eat phytoplankton
have been stripped of an essential food source, he said.
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- In New England, a type of Japanese algae
is now aggressively taking root along the coast. Meanwhile, an organism
from New England - called a comb jelly - was exported to the Black Sea
and has decimated an economically important anchovy fishery.
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- One thing scientists did in the past
was introduce predator species to control invaders. But now, fearing new
species could further threaten ecosystems, scientists have been developing
methods that would stop the invaders before they make it to foreign waters.
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- Babbitt on Tuesday called for mandatory
ballast water exchange programs and urged Congress to work on bioinvasion
before it becomes a crisis.
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- Proposals include giving agencies the
muscle to enforce what could amount to international regulations, he said.
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- Ballast exchange programs would require
a ship coming from the Mediterranean, for example, to dump its ballast
water in the deep seas - at least 200 miles from shore and about 2,000
feet deep - then replace it with deep sea water.
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- The theory is that organisms found in
deep sea water have a harder time surviving in water closer to the coasts,
and vice versa.
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