Oceans heading for mass extinctions, experts warn

http://www.msnbc.msn.com/id/43479398/ns/world_news-world_environment/

updated 6/21/2011 12:15:31 PM ET

WASHINGTON — Mass extinctions of species in the world's oceans are inevitable if current trends of overfishing, habitat loss, global warming and pollution continue, a panel of renowned marine scientists warned Tuesday.

The combination of problems suggests there's a brewing worldwide die-off of species that would rival past mass extinctions, the 27 scientists said in a preliminary report presented to the United Nations.

Vanishing species — from sea turtles to coral — would upend the ocean's ecosystem. Fish are the main source of protein for a fifth of the world's population and the seas cycle oxygen and help absorb carbon dioxide, the main greenhouse gas from human activities.

"Things seem to be going wrong on several different levels," said Carl Lundin, director of global marine programs at the International Union for Conservation of Nature, which helped produce the report with the International Programme on the State of the Ocean.

Some of the changes affecting the world's seas — which have been warned about individually in the past — are happening faster than the worst case scenarios that were predicted just a few years ago, the report said.

"It was a more dire report than any of us thought because we look at our own little issues," Lundin said. "When you put them all together, it's a pretty bleak situation."

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The chief causes for extinctions at the moment are overfishing and habitat loss, but global warming is "increasingly adding to this," the report said.

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Lundin said that "some of these things are reversible if we change our behavior."
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Overfishing is the easiest for governments to address, the experts said.

"Unlike climate change, it can be directly, immediately and effectively tackled by policy change," said William Cheung of the University of East Anglia. "Overfishing is now estimated to account for over 60 percent of the known local and global extinction of marine fishes."

Among examples of overfishing are the Chinese bahaba. Its swim bladder is desired in Asia as a medicinal product, and the cost per kilo (2.2 pounds) has risen from a few dollars in the 1930s to $20,000-$70,000 today.

Listed as critically endangered, the bahaba is just one of more than 500 marine species threatened by overfishing, Cheung noted. "The only chance for many of these species to recover is to stop overfishing and protect them so that the populations can rebuild," he added.

"If action is not taken immediately, our generation will see many more species follow the footsteps of the Chinese bahaba," Cheung said.

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But he noted that in the United States "a strong set of management requirements backed by the force of law have resulted in an end to domestic overfishing."

"This is of course a very hopeful sign because the USA is such an important fishing nation," he added. "Is the record commensurate globally? No it is not, and thus I would certainly support" the panel's advice to reduce global fishing "to levels commensurate with long-term sustainability of fisheries and the marine environment."

The Associated Press and Reuters contributed to this report.

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