Assisted coral fertilization offers hope as Dominican reefs decline

In the Dominican Republic, scientists and conservationists are turning to assisted coral fertilization to counter a drastic decline in reefs caused by warming oceans. Fundemar, a marine conservation organization, operates a laboratory and nurseries where coral eggs and sperm are joined in a process akin to in vitro fertilization. The aim is to create genetically diverse corals that can be transplanted back to the reef, giving the ecosystem a chance to recover even as natural reproduction becomes increasingly unlikely.

Fundemar’s latest monitoring shows the scale of the challenge: about 70% of the Dominican Republic’s reefs have less than 5% coral coverage. On degraded reefs, coral spawning is less likely to produce viable offspring, and colonies are so dispersed that fertilization events in the wild are far less common than in healthier reefs. “We live on an island. We depend entirely on coral reefs, and seeing them all disappear is really depressing,” said Michael del Rosario, a conservationist who works with Fundemar. “But seeing our coral babies growing, alive, in the sea gives us hope, which is what we were losing.”

The program produces more than 2.5 million coral embryos each year in laboratory settings. Of those, roughly 1% are expected to survive once released into the ocean—a figure that, while daunting, is still an improvement over natural fertilization rates on damaged reefs today. Andreina Valdez, Fundemar’s operations manager, notes that the shift from traditional transplantation of coral fragments to sexual reproduction seeks to introduce genetic variety, reducing the risk that a disease could wipe out an entire population.

"We used to focus on asexual reproduction, cutting pieces from healthy corals and transplanting them. That can yield faster growth, but it clones the same genotype, leaving populations vulnerable to disease," Valdez said at the organization’s new marine research center. “Assisted reproduction creates genetically different individuals, increasing the odds that some will survive as the environment changes.”

Australia pioneered assisted coral fertilization, and the approach has gained momentum in the Caribbean, with active work noted at the National Autonomous University of Mexico and the Carmabi Foundation in Curaçao. Valdez said the technique is also being adopted in Puerto Rico, Cuba and Jamaica. “You can’t conserve something if you don’t have it. So these programs are helping to expand the population that’s out there,” added Mark Eakin, the International Coral Reef Society’s corresponding secretary and a former NOAA official. Still, he cautioned that climate change remains the dominant threat: without addressing greenhouse gas emissions, restoration work risks being undone.

Burning fossil fuels has driven ocean warming to levels unprecedented in recent history. UNESCO’s State of the Ocean Report notes that seas are warming at roughly twice the pace they did two decades ago. Elevated temperatures trigger coral bleaching, a stress response in which corals expel the symbiotic algae that give them their color and nourishment. Bleached corals may recover if conditions improve, but prolonged heat leaves them weak and susceptible to disease and death. Amid these dynamics, reefs in the Dominican Republic and across the Caribbean serve as natural barriers that dissipate wave energy, protecting coastlines and the tourism economy that depends on beaches and healthy reefs.

What’s happening in the Dominican Republic matters beyond the reef itself. Beaches, tourism infrastructure, and fisheries—already strained by overfishing and habitat loss—depend on reef health. Del Rosario recalls how reefs once sheltered coastal beaches and supported local livelihoods. “What do we sell in the Dominican Republic? Beaches,” he said. “If we don’t have corals, we lose coastal protection, we lose the sand on our beaches, and we lose tourism.” Corals are also home to more than a quarter of all marine life, underscoring their importance to millions who rely on the sea for food and income.

The human impact of reef decline is personal as well. Alido Luis Báez, a Bayahibe fisherman, recalls how much fishing has changed since his father’s era. They used to remain close to shore, but overfishing, habitat loss and climate stress now push them farther offshore—up to 50 miles in some cases—to catch tuna, dorado and marlin. “We didn’t have to go so far before,” Báez said. “But because of overfishing, habitat loss, and climate change, now you have to go a little further every day.” His comments underscore the urgency of reef restoration as a component of broader efforts to sustain coastal communities.

Del Rosario remains cautiously optimistic about the path forward. He argues that while there is no single solution to reef decline, the combination of reduced emissions, improved local stewardship, and active restoration can slow the loss and buy time for corals to recover. “More needs to be done, of course ... but we are investing a lot of effort and time to preserve what we love so much,” he said. “And we trust and believe that many people around the world are doing the same.”

The Dominican Republic’s reef work sits within a global climate and environmental context in which restoring biodiversity is increasingly viewed as essential, not optional. As scientists expand the use of assisted fertilization, they say the focus must be on reducing the climate stress that enables mass bleaching and mortality. The reef’s future depends on a combination of local action and national and international commitment to cut emissions, protect habitats, and support science-driven restoration efforts that embrace genetic diversity and resilience. The work in Bayahibe is one piece of a broader, evolving effort to safeguard the planet’s coral ecosystems for generations to come.