Our Efforts on Coral Reef Restoration in Puerto Rico

Updated: Apr 19


Young Diadema antillarum collected from the southern shelf edge in La Parguera, Puerto Rico

For the past couple of years, ISER has strived to protect and conserve the natural ecosystems of Puerto Rico and the greater Caribbean. Our projects have included the installation of green infrastructure, rain gardens and the coastal restoration by the planting of trees at Playa de Ponce, to protect marine habitats, like seagrasses, from beach erosion and land-based pollutants. We have dedicated a lot of our time in protecting the coral reef habitats. Coral reefs, both shallow and deep, provide many economic and biological services in Puerto Rico. Reefs are extremely important because they act as a natural barrier providing coastal protection, dissipating waves during storms and/or hurricanes as seen by the passing of Hurricane Irma and Maria, and provide livelihoods to fishers and an important food source. ISER is currently leading two important coral reef projects, sea urchin restoration and the microfragmentation and restoration of massive corals.



Diadema Restoration


The long-spined sea urchin, Diadema antillarum, is an important component for the health and resilience of Caribbean coral reefs. During the early ‘80s, there was a massive die-off of this sea urchin throughout the Caribbean. For the past couple of years, ISER has developed a novel approach in the restoration of this important sea urchin. The lead scientist, Stacey Williams, along with graduate students and scientists collect post-larval settlers of Diadema and bring them back to grow them in saltwater tanks at the Department of Marine Science at the UPRM. When collected, the settlers are very small, less than 1mm in size. It takes about one year for the urchins to grow the young adults (3-4 cm) in tanks. Once they are big enough, the Diadema are then transferred to different coral reefs around Puerto Rico. So far, we have restored over 2,000 sea urchins to reefs in Fajardo, Guayanilla, and La Parguera. ISER is guiding other scientists at the University of Virgin Islands, USVI and the Netherlands, Saba, and St. Eustatius to develop this same restoration technique in their perspective islands.


Diadema restoration is needed more than ever today. There is an aggressive encrusting alga called Ramicrusta that is spreading all over Puerto Rico. This alga is dangerous because it can overgrow and kill corals and other organisms. Parrotfish and surgeonfish, both herbivores, seem not to like eating this alga. However, Dr. Williams did a small lab experiment and brought back pieces of Ramicrusta to the wet lab, and sure enough, Diadema eats Ramicrusta! In 2018, Dr. Williams restored close to 500 Diadema to two reefs in Fajardo. Ramicrusta is the dominant substrate at these two reefs, with cover as high as 60%. In two months, Diadema decreased the cover of Ramicrusta by 63%. You can read the report below for more details.


This summer we are planning to restore between 400-600 Diadema to two reefs in Cabo Rojo.


Two of the indoor aquaria that hold the young and small Diadema antillarum before they are transferred to the outdoor aquaria that hold the adult Diadema that will be transferred to the coral reefs in southwest Puerto Rico.

Coral Restoration



Fragmented sections of coral that will be cultured and transplanted to coral reefs in southwestern Puerto Rico

To increase coral populations and combat reef degradation, scientists from all over the region have carried out restoration efforts. Benefits of coral restoration include the increase in coral cover, coral larval supply, and recruitment of fish and other benthic organisms, and structural complexity. So far all restoration efforts in the Caribbean have taken a monospecific approach, by mainly restocking scleractinian corals, specifically the staghorn coral, Acropora cervicornis.


ISER, along with Dr. Ernesto Weil, professor at the Department of Marine Science, UPRM and the NOAA Restoration Center has developed the first land-based coral nursery in Puerto Rico. At the land-based nursery, we are testing the novel approach of microfragmenting to restore slow-growing massive/encrusting corals. We are microfragmenting other ESA coral species such as the boulder star coral, Orbicella annularis complex, and the pillar coral, Dendrogyra cylindrus. We will produce a seed bank of these ESA colonies, along with a database of their habitat survivorship history and genome-wide genetic information. We expect to provide thousands of coral microfrags for restoration purposes.


Students, staff and faculty fragmenting coral sections for culturing.

The overall goal of this project is to advance natural recovery by re-establishing genetically connected populations with high genotypic diversity that promote successful sexual reproduction and natural recovery of the targeted foundational species. We want to provide an alternative and more effective restoration technique to increase the survivorships of outplanted corals. In addition, we will foster the education of students for master and doctorate degrees in science and restoration studies. The land-based nursery is located at the Marine Science Department (CIMA). CIMA is a leading research center in the Caribbean and hosts a number of local school groups for educational talks about marine ecosystems. We hope the restoration center can be used as an educational and research tool for students from elementary to graduate school.


Stay tuned for developments! Follow us on Twitter, Facebook, and Instagram @isercaribe.