Significant Coral Bleaching Recorded in 2011

Florida reefs experience worst bleaching since detailed studies began six years ago.

ALTAMONTE SPRINGS, FL | December 09, 2011

The summer of 2011 saw almost the entire Florida Reef Tract, from the Lower Keys to Martin County, suffer coral bleaching, the most extensive coral bleaching event since detailed monitoring began in 2005. The results were tabulated by The Nature Conservancy from monitoring done between August 8 and October 14 through the Florida Reef Resilience Program (FRRP).

“I don’t think it’s a coincidence that coral bleaching was so prevalent given that to date 2011 is tied for the tenth hottest year on record. This is troubling because this is a La Nina year and these are supposed to be cooler than normal here in South Florida,” said Chris Bergh, director of coastal and marine resilience for The Nature Conservancy’s Florida Chapter.

The FRRP is a collaborative effort among managers, scientists, conservation organizations and reef users to develop resilience-based management strategies for coping with climate change and other stresses on Florida’s coral reefs. With projected increases in coral bleaching due to climate change, the FRRP Disturbance Response Monitoring (DRM) was created to check the condition of shallow coral reefs from the Florida Keys to Martin County during the annual period of peak heat stress.

Corals often respond to stress by expelling the colorful algae that live within their otherwise clear tissues. This phenomenon is called "coral bleaching" because it reveals the stark white coral skeleton. Surveying reefs that experience coral bleaching can provide clues to a given coral species' or a given reef area's resilience by determining which corals and reefs resist bleaching and which "bleach" but then recover rather than perish. Weakened reefs are susceptible to disease; dead reefs mean less habitat for fish, spiny lobster and other marine life. Bleaching is a major contributor to the decline of reefs worldwide.

This year, 13 survey teams from federal, state and local government agencies, universities and non-governmental organizations cooperated to survey 234 sites within a nine-week period. The sites were spread across 23 reef zones in seven subregions of the south Florida Reef Tract.

Bleaching and paling of 21 percent to 50 percent of coral colonies was found in the Lower, Middle and Upper Keys and in the Broward, Biscayne and Martin subregions. Bleaching and paling of zero to 20 percent of coral colonies occurred at inshore sections of the Middle and Upper Keys and in the Broward, Biscayne and Palm Beach subregions.

For more information about the Florida Reef Resilience Program and its Disturbance Response Monitoring effort see the website For more information about the 2011 Disturbance Response Monitoring results contact The Nature Conservancy Florida Keys office at (305) 745-8402 or email James Byrne, marine science program manager, at

office at (305) 745-8402 or email James Byrne, marine science program manager, at

The Nature Conservancy is a leading conservation organization working around the world to protect ecologically important lands and waters for nature and people. The Conservancy and its more than 1 million members have protected nearly 120 million acres worldwide. Visit The Nature Conservancy on the Web at

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