Charting the Path to Caribbean Coral Reef Recovery

April 2015

Protecting parrotfish and strengthening coastal zone management may be the keys to increasing resilience of Caribbean coral reefs, according to coral reef ecologist Jeremy Jackson, PhD.

Later this month, Jackson will share his insights on the status of coral reefs in the region and the path to protecting them with the Florida Keys National Marine Sanctuary’s Advisory Council at their April 21 meeting in Key West.

Once nicknamed “Dr. Doom” for his dire descriptions of declines of Caribbean reefs, Jackson has shifted focus to explaining the findings of a major scientific report and promoting positive actions that can be taken to aid in their recovery.

Healthy elkhorn corals in 1975 image and sparse elkhorn corals in 2004 image. This set of images comparing 1975 conditions to 2004 conditions on Carysfort Reef appeared in Jackson's 2014 Caribbean-wide report. Credit: Phillip Dustan

“Most people under 50 haven’t seen a healthy coral reef,” said Jackson in a December 2014 talk he gave to NOAA’s National Marine Protected Area program. “We want to know when and why did the degradation occur, and what we might do to stop it and restore reefs to a more desirable level of ecosystem health…that was the whole purpose of the coral reef monitoring network study.”

An iconic set of photographs from Florida Keys National Marine Sanctuary’s own Carysfort Reef provides a visual of coral declines in the 2014 report that Jackson led: “Status and Trends of Caribbean Coral Reefs: 1970-2012.” A 1975 Carysfort image shows a continuous cover of elkhorn coral, branches emanating a deep orange glow at an upward-facing angle that adds to the effect that the color seems to glow from below like the last moments of a tropical sunset. In contrast, a 2004 photograph at the same site shows a sparse few elkhorn corals surrounded by a stark whitish-grey rubble.

Striking as the photographic contrast is, the report’s massive baseline of hard scientific data is even more impressive. The three-year, Caribbean-wide study released last year was compiled by nearly 200 experts, drawing from more than 35,000 quantitative surveys at 90 reefs throughout the region. This included 21 reefs where monitoring data predated a critical massive 1983 bleaching event.

Monitoring data suggests reefs throughout the region began to decline around the same time as the massive die-off of long-spined Diadema sea urchins, which also started in 1983. These important grazers once kept algae from growing over corals, before they were decimated by a disease that spread throughout the Caribbean basin. Ecologists call such species “ecosystem engineers” because their actions help shape the entire ecosystem. Today, Diadema sea urchin recovery has been slow and they remain at only a fraction of their original numbers.

Blue fish swimming. Parrotfish may be a key factor in protecting healthy coral reefs in the Caribbean, because their grazing suppresses algal growth on corals. Click for high resolution version.

The only silver lining? Another herbivore appears to keep algae in check on many of the region’s coral reefs: parrotfish.

“Without [parrotfish] and other herbivores, algae and seaweed would overgrow the reefs, suppress coral growth and threaten the incredible array of life that depends on these reefs for shelter and food,” wrote Jackson and co-author Ayana Johnson in a New York Times editorial last September.

He then urged the importance of looking for lessons from the monitoring data, likening coral reef research and monitoring without management actions to “a doctor analyzing a patient’s decline without doing everything possible to save her life.”

The public is invited to learn more the report’s findings and Jackson’s recommendations for supporting reef recovery at his talk, which starts at 10:35 a.m. on April 21, at The Westin Key West Resort and Marina, 245 Front Street, Key West, Fla., 33040.

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