For coral conservation, underwater nurseries.

By Lindsay Fendt

A solitary block of pale-yellow branching corals rises from the white-sand ocean bottom just off the coast of Punta Cana, a tourism center at the easternmost tip of the Dominican Republic. Schools of small fish weave in and out of the crevices. They’re staking out a rare hiding spot—a critically endangered coral that has been painstakingly cultivated by the Puntacana Ecological Foundation, an environmental organization here.
This staghorn coral (Acropora cervicornis) the fish are swimming through is among a group of corals that in the last 30 years has seen drastic population declines in the reefs of the Dominican Republic and much of the Caribbean. But while their numbers remain alarmingly low in the wild, the corals thrive on the ropes and A-frame metal structures in manmade underwater coral gardens created by the foundation.

The gardens, once considered a last-ditch preservation effort, have proven to be an effective tool for repopulating the Dominican Republic coast’s shrinking reefs. Scientists, conservationists and even tourists are now teaming up to expand the project’s scope in hopes of saving these crucial marine habitats.

In the late 1970s and early 1980s, a never-before-seen coral disease swept across the entire Caribbean, turning once healthy corals into dead, white rocks. The disease affected acroporid corals, which are the primary reef builders in the region, making them crucial to the structural integrity of the reefs.

Biologists named the mysterious illness white band disease for the characteristic white strips of dead coral it left behind. Able to spread up to one centimeter per day, white band disease proliferated
quickly on its own, but the disease was elevated to a full-blown epidemic due to a massive die-off of Diadema sea-urchins. Without the urchins to graze on the reefs, an overabundance of seaweed built up
on the coral, trapping bacteria.

During this period, 95% of the region’s staghorn and elkhorn (Acropora palmata) corals died off and other species of acroporid corals were severely affected. In the decades since the outbreak, scientists
have been unable to pinpoint the source of either white band disease or the urchin deaths, though new studies indicate the former may have been spurred by improper sewage disposal. Despite conservation
efforts to cut down on coastal pollution in the Dominican Republic, the island’s reefs continue to face white band disease and other threats to their survival.

Notable among the other threats is coral bleaching, which can occur when an increase in water temperature causes coral to eject symbiotic algae that helps sustain it. Though the coral turns white, it
can still be alive; but it is at a heightened risk of dying.

Since the turn of the century, rising water temperatures have pushed the island’s reefs into three mass coral bleaching events. The most extreme of these events to hit the Caribbean, in 2005, bleached
68% of the Dominican Republic’s corals, killing 11%.

Overfishing also continues to take a severe toll on the local reefs. According to environmental groups, more than half of the average fishing catch is made up of parrotfish, which, like sea-urchins, graze on and clean coral reefs. The overfishing of crab, lobster and hogfish has also led to an overabundance of their coral-eating prey, which include fireworms, damselfish and coralliophila.

Overall, approximately 75% of the world’s coral reefs are considered threatened by climate change and human coastal activities. In the Dominican Republic these problems are especially severe due to the region’s vulnerability to extreme temperature change and the presence in the region of large coastal populations.

The degradation of the Dominican Republic’s reefs has alarmed business owners as well as environmentalists. According to government data, tourism in 2014 made up 16% of the country’s GDP, and one in six tourists list the beaches as their primary reason for choosing the Dominican Republic as a vacation spot. A 2010 study by the World Resources Institute estimated that the current rate of coral degradation in the country causes beach erosion that could lead to revenue losses of US$52 million to $100 million by 2020.

“Coral reefs produce a lot of the sand and they provide most of the shore protection, so when they disappear those services go away,” says Víctor Galván, ecological research coordinator for the Puntacana Ecological Foundation’s coral gardens. “People started to get worried and wanted to do something.”

Contacts
Victor Galvan - Coordinator Ecological Research                Mark Goldsmith
Puntacana Ecological Foundation                                             Dive instructor - Blue Vision Adventures
Punta Cana, Dominican Republic                                              Punta Cana, Dominican Republic
Tel: +(809) 959-9221                                                                  Tel: +(829) 764-1829
[email protected]                                                           [email protected]