A rehabilitation program for coral reef species has proven to be successful for an ongoing project to combat a massive disease spreading throughout the Cayman’s pillar coral species, according to the Department of the Environment in the Cayman Islands. The rapidly spreading disease, called “white band disease”, was first noticed on a famous dive site called the Killer Pillars in February 2018. It has ravaged pillar coral throughout the Caribbean and destroyed almost 90 percent of the species along the Florida coast.
Scientists in the Cayman Islands removed diseased coral from the reef and selected healthy fragments to grow in a nursery. They later planted healthy coral back onto the reef, in hopes the fragments became resilient enough to resist the disease and build back the reef. Though the project is still an experiment, the results look promising thus far and can have wide implications on how other islands respond to this disease throughout the region.
Throughout the world, coral reefs are seriously vulnerable and rapidly dying. Reefs are thought to host the most biodiversity of any ecosystem in the world– even more than a rainforest. Despite their importance, reefs are critically vulnerable to small changes in the environment. Slight increases in ocean temperature cause widespread die-off throughout Caribbean and Pacific reefs. Additional threats include pollution, over fishing and run-off of nitrogen from farms that fertilize algae and causes it to smother reefs.
Abandoned fishing gear also wreaks havoc on reefs and creates an opportunity for disease. “Fishing line not only causes coral tissue injuries and skeleton damage, but also provides an additional surface for potential pathogens to colonize, increasing their capacity to infect wounds caused by entangled fishing line,” says Dr. Joleah Lamb from the Centre of Excellence for Coral Reef Studies at Australia’s Great Barrier Reef.
Coral reefs are home to nearly 25 percent of all marine species and sustain the fishing industry. They are paramount to Caribbean economies and are an important defense for small islands and coastal communities during hurricanes. Evidence shows their structures reduce damaging wave energy by nearly 97 percent. Also, reefs attract dive tourists and help build beaches by breaking down into sand. Experiments such as the one in the Cayman Islands are critically important for ensuring the reefs that do remain, are healthy and functioning.
How does the project in the Cayman Islands work?
Along with marine scientists from the U.K. and U.S., coral experts from the Department of the Environment removed diseased coral from the reef in order to stem the alarming spread of the disease. They then cut segments of healthy coral to regrow in nurseries.
Coral nurseries, a growing trend in coral restoration, are structures constructed in clean, sandy sections of the ocean floor. Scientists attach healthy coral fragments to the simple structures, often made out of PVC pipe, and monitor them as they grow in a safe environment. Once the corals are strong, healthy and considerably larger in size than the original fragments, the scientists plant them back onto the original reef or select new sites to start a reef.
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Impressively, 100 percent of the coral fragments in the Department of Environment’s nursery survived. Coral nurseries are a restoration technique popular throughout the Caribbean basin, including Bonaire, Curacao, Grenada, the Virgin Islands and many restoration and research laboratories in Florida.
After their successful growth in the nursery, 81 percent of the fragments re-planted were still alive after five months. This is a considerable success rate given the threats these corals face. However, 23 percent of the planted fragments also showed signs of the relentless “white band disease” (Acroporid white syndrome).
Researchers have not given up hope and recognize that if kept contained, disease can be a natural part of ecosystems. “We do know that diseases have their seasons, they come and go, they are vigorous for a while and then they die back, and at that point we have to see some kind of coral colony recovery,” Tim Austin, Deputy Director of the Department of Environment, told Cayman 27 News. “We are monitoring it and we are hoping to have a better handle on how this disease progresses.”
In addition to techniques such as reducing marine debris, pollution and establishing protected conservation zones around reefs, coral salvage projects are an important technique to ensure that Caribbean’s the remaining corals survive.
“If longer-term monitoring results prove equally successful, the salvage, relocation and restoration of actively diseased coral colonies could become an everyday tool in the restoration toolbox of coral reef managers,” the Department of Environment reported.
Via Yale 360
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