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Healthy Coral Reefs Require Parrot Fish

By Don Rhodes

Green Parrot Fish
Green Parrot Fish

While drifting along on a shallow ledge on Conch Reef, I spot a group of colorful parrot fish chomping away at algae and other growth on the coral. A bit farther I see a massive plume of white debris blast from the tail end of a large parrot fish. “What goes in must come out,” I think.

Turns out parrot fish, while eating algae and seaweed, are doing their part to keep the reef healthy. Without them and other sea-dwelling plant eaters, algae and seaweed would overgrow the reefs, suppress coral growth and threaten the incredible array of life that depends on reefs for shelter and food. Healthy coral reefs are important for the Florida Keys. They provide shoreline protection and support our tourism, sport fishing and diving businesses.

A detailed report, Status and Trends of Caribbean Coral Reefs: 1970-2012 says that Caribbean corals have declined by more than 50 percent since the 1970s. A set of photographs in the report illustrates the decline of the Key’s reefs. In 1975 Carysfort Reef had a continuous cover of elkhorn coral. In contrast, a 2004 image shows a sparse elkhorn coral population surrounded by a ghostly whitish-gray rubble. The report, the result of a three-year Caribbean-wide study, was compiled by nearly 200 experts, drawing from more than 35,000 quantitative surveys at 90 reefs throughout the region including 21 reefs where monitoring data predated a critical massive 1983 bleaching event.

Elkhorn Coral

Many of us are aware of the effect climate change has on coral reef. But, according to the report, climate is only one of the culprits killing the coral reef. “While it is true that climate change poses an enormous risk for the future because of coral bleaching and more acid oceans, reefs protected from overfishing and excessive coastal development and pollution are more resilient to these stresses. Healthy reefs will bounce back faster after damaging extreme heating events and hurricanes,” according to coral reef ecologist Jeremy Jackson, Ph.D., lead author of the report. According to Jackson, reefs near islands with effective local protections and governance have double the amount of living coral compared with those that lack those protections. They also have more fish and clearer waters.

A main culprit in the decline of healthy coral is the loss of parrot fish and other grazers (such as long-spined Diadema sea urchins), which the report says has been a more significant factor than climate change in the destruction of Caribbean reefs. In 1990 Bermuda banned fish traps that were decimating the parrot fish population. “Today, Bermuda’s coral reefs are relatively healthy, a bright spot in the wider Caribbean,” Jackson said. It seems restoring parrot fish populations and improving other management strategies to curtail overfishing, invasive species and coastal pollution could help the reefs recover and make them more resilient to the effects of climate change. “We must immediately address the grazing problem for the reefs to stand any chance of surviving future climate shifts,” Jackson emphasized.

Parrot Fish

Without parrot fish 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, Ph.D., in a Sept.18, 2014 New York Times guest editorial. (See: has special challenges, according to Jackson and Johnson. “In Florida, banning fish traps — which should result in more parrot fish, less algae and more coral — has not stemmed coral decline,” they wrote. “That’s because of extreme local pressures from millions of residents and tourists and insufficient controls on development. “We need to move immediately beyond listings of species as threatened and research about climate change and take rigorous action against the local and global stresses killing corals.“

Monitoring and research are vitally important, but collecting information without strong corrective action is like a doctor analyzing a patient’s decline without doing everything possible to save her life. “To save coral reefs, we need to follow the lead of Barbuda and our other proactive neighbors. We need to stop all forms of overfishing, establish large and effectively enforced marine protected areas and impose strict regulations on coastal development and pollution while at the same time working to reduce fossil fuel emissions driving climate change. It’s not either/or. It’s all of the above,” concluded Jackson and Johnson in their guest editorial.

Jackson shared 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 its April 21 meeting in Key West. To see a recording of Jackson’s presentation go to: This is a 4.5 hour video but Dr. Jeremy Jackson’s presentation starts at the 26 minute mark and runs for about 2 hours.

So, the next parrot fish you see is more than just a pretty face. It is helping to protect our valuable coral reefs.

Source: Healthy coral reefs require protection for species such as parrot fish | Miami Herald Miami Herald

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