Michael Casey, Business Week 17 Feb 10;
Marine parks that limit fishing and other human activity can help shrinking coral reefs halt their decline over several years and even start growing again, a study released Wednesday found.
Earlier studies have found that fish populations increase in response to no-fishing zones. But the study in the peer-reviewed science journal PLoS ONE is the first to show that reefs also may gain from such protection.
The study by University of North Carolina marine scientists Elizabeth Selig and John Bruno analyzed a global database of 8,534 live coral cover surveys between 1969 and 2006. They found that corals located in marine reserves halt their declines and, in some cases, increase their cover.
"We found that on average, coral cover in protected areas remains constant, but declined on unprotected reefs," Selig, the study's lead author, said in a statement.
Bruno said the reefs do not respond initially to the increased protection, but over several years they show signs of recovering. For example, in the Caribbean, he said the surveys found that coverage declined for about 14 years before steadying and then increasing.
In the Indo-Pacific, cover kept declining for the first five years after protections were established and then improved, reaching growth rates of 2 percent yearly after two decades.
"Given the time it takes to maximize these benefits, it makes sense to establish more marine protected areas," Bruno said in a statement. "Authorities also need to strengthen efforts to enforce the rules in existing areas."
Corals serve as breeding grounds and habitat for many of the world's marine species and act as indicators of overall ocean health. They are under threat from pollution and overfishing and increasingly from global warming.
A 2007 study published in the journal Science warned that if carbon dioxide emissions continue at today's rate, all corals could be extinct within 100 years.
Gregor Hodgson, executive director of the California-based conservation group Reef Check Foundation and who was not involved in the study, said a survey of this size in PLoS ONE was "very important" because it allows researchers to see emerging patterns with reefs.
"It also shows some management was better than none," Hodgson said.
The study also appears to challenge an earlier one that found that marine parks offered little protection to reefs.
