Spending hours a day diving around the coral reefs off St. Croix might sound like the stuff of a dream vacation, but for Annie Opel ’17, it was serious business.
Opel spent much of her Virgin Islands adventure on thesis research that shows that efforts to restore coral reefs have a positive impact on fish populations, both short- and long-term. The study was published in the December issue of Marine Biology with Opel as first author, a rare accomplishment for an undergraduate.
“Reefs are not only biologically important — more than 4,000 species of fish rely on these ecosystems — they’re also really important for humans,” Opel said. “We depend on them for commercial and recreational fisheries, they provide protection for coastal communities, and they bring in a great deal of money through tourism.
“But right now they’re threatened by a number of anthropogenic inputs, from pollution to the effects of climate change,” Opel said. “Coral reefs have experienced bleaching and mass mortality all over the world, causing ecosystem degradation that affects the marine life that rely on the reefs to survive.”
While there have been efforts to counter those threats by transplanting corals grown in underwater “nurseries” to damaged reefs, the impact of such projects on Caribbean reefs has been an open question, Opel said.
“In St. Croix, they’ve been restoring corals since 2009,” Opel said. “[But] no one is really looking at what’s happening after the fact … so no one knows if this is an efficient way to restore reef systems.”
What she found, Opel said, is that as little as a week after the introduction of experimental coral beds, significantly more fish and a greater diversity of species appeared. The research also showed that, over time, the fish community changed as additional species began visiting the sites.
“Overall, it’s a success story — we outplanted corals and there were more fish,” she said. “That’s really exciting and something people took for granted in these restoration projects, but no one had quantified it before. I think it’s going to be interesting for future studies to use this as a benchmark to know what’s going on after transplanting corals.”