September 8th, 2012 by James Ayre
The coral reefs of the Caribbean have, to put it bluntly, completely collapsed. Overfishing and climate change are the primary causes according to a new report released by the International Union for Conservation of Nature (IUCN).
In the most comprehensive study yet of Caribbean coral reefs, scientists have discovered that the 50 to 60 percent coral cover present in the 1970s has plummeted to less than 10 percent.
“I’m sad to tell you it’s a dire picture,” Carl Gustaf Lundin, director of IUCN’s Global Marine and Polar Programme, said at a news briefing Friday at the World Conservation Congress in Jeju Island, South Korea.
One of the main forces that set this decline into motion was the massive die-off of sea urchins in the 1970s, which was possibly caused by human introduced disease. “Without these reef grazers—the ‘cows in the field’ that keep vegetation in check—the number of algae and grasses have skyrocketed, dominating reefs and pushing corals aside,” Lundin said.
“What’s more, overfishing of grazer species such as parrotfish or surgeonfish is allowing more algae to take over and outcompete the coral, said Ameer Abdulla, IUCN senior advisor on Marine Biodiversity and Conservation Science.”
“Coral reef communities are just like human communities—there are different roles that are fundamental to keeping the system going,” Abdulla said.
“For example, if all the engineers were taken out of a human society, that would affect how the society functions.”
“The scientists also said that warmer water—often caused by hurricanes blowing through—have harmed reefs. When the water gets too hot, algae that live inside coral, called zooxanthellae—abandon their hosts, causing the coral themselves to bleach and eventually die.”
“Though some reefs can bounce back from such periods of warmer water, notably in the Indian Ocean, we have heating happening with much higher frequency and for longer duration,” Lundin told National Geographic News.
“For instance, some 500-to-a-thousand-year-old corals in the Indian Ocean have died due to warmer water.”
“We know with some certainty we haven’t had this happen for a thousand years, that’s a clear indication that something’s afoot,” Lundin said.
“For those that are very skeptical of what’s happening with climate change, I would say reality is not in their favor.”
“Corals are vital for many reasons, from boosting tourism dollars to local communities and even buffeting islands themselves from powerful storm surges,” Lundin said.
“The good news is that there are ways to protect the remaining 10 percent of Caribbean corals.”
“The urgency of improving management is certainly there—our message is we need to encourage the people who are the custodians of the resources to take charge. We do know a lot about what one can do,” said Lundin.
“For instance, putting in place marine protected areas can reduce the pressure of overfishing. Governments can also work with local fishers to maintain their livelihoods, for instance by raising the value of individual fish so that the fishers catch fewer animals.”
The stark truth of it is that “the Caribbean system is (just) one of (the) first systems to experience collapse—it’s something that will happen across the globe if human use of coral reefs continues as it is.”
Image Credits: Baums lab/Penn State University
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