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Economies of scale: marine reserves could reverse declines in fish stocks, researchers say. Credit: AP

Protected 'marine reserves' off the coasts of the United States received unequivocal support this week in a statement issued by 160 prominent marine scientists. The group declared that there is now evidence that these reserves are effective as conservation tools.

The statement was crafted by the National Center for Ecological Analysis and Synthesis at the University of California at Santa Barbara, and was released at the annual meeting of the American Association for the Advancement of Science in San Francisco. It was issued in response to indications that the US government is preparing to stall plans to establish a network of the reserves.

“The message is clear,” says Jane Lubchenco, a marine biologist at Oregon State University and one of the statement's signatories. “Marine reserves work, they work quickly, and they are a powerful and underutilized tool. Existing scientific information justifies immediate application of networks of marine reserves as a central management tool,” she says.

In May of last year, former president Bill Clinton issued an executive order requiring a study of marine protected areas, where some activities are prohibited. The executive order also called for the planning of a network of such areas, probably including a small area of 'marine reserves', where no resource removal of any kind is permitted.

But in January, James Hansen (Republican, Utah), the new chairman of the powerful resources committee in the House of Representatives, sent a letter to the incoming administration of President George W. Bush. In it, he urged Bush to slow down any movement towards a network of marine protected areas, due to what he termed insufficient knowledge on their effectiveness.

Lubchenco says that, although a few years ago this was the case, the present state of knowledge makes it clear that the marine reserves would work.

The latest statement was released in conjunction with the results from several marine reserve studies to be published in a forthcoming issue of Ecological Applications. One, led by Robert Warner of the University of California at Santa Barbara, examined data on 81 marine reserves around the world and found almost universal and dramatic increases in population densities, organism size and species diversity within the reserves.

Roger Griffis, policy adviser for the National Oceanic and Atmospheric Administration, says that fishermen are still concerned that reserves will harm their business. But he notes that reserves may actually prevent further declines in catches.

Griffis adds that the decline of marine resources has reached a critical point and that, although study of reserves should continue, the recent studies amply show their effectiveness. “We do know enough to be acting,” he says.