Mass-reared elkhorn corals are thriving on the reef
In August 2017, our field team in Curaçao successfully reared elkhorn coral larvae (Acropora palmata) in one of our first in situ larval rearing pools, designed by SECORE International with the help of Mark Schick and Keoki Burton (Shedd Aquarium). We stocked the pools with approximately 150,000 A. palmata embryos on the night of spawning, along with 500 pre-conditioned first generation SECORE tetrapods on which they could settle. Two weeks later, an average of 34 coral larvae had successfully settled on each tetrapod, resulting in the formation of approximately 17,000 new coral babies. Shortly afterwards these were outplanted on 10 different breakwalls along the leeward coast of Curaçao. (A breakwall is typically an in-water wall that runs along a coastline, designed to protect the shore from the impact of waves.)
Kelly Latijnhouwers (SECORE International) and Evan Culbertson (Virginia Aquarium) pouring fertilized embryos into the larval rearing pool on the night of August 17th 2017, corresponding to 10 days after the full moon. (Christian van Bijnen)
During April and May this year, SECORE’s Restoration Technician Kelly Latijnhouwers and Research Scientist Valerie Chamberland re-visited these breakwalls and found many thriving A. palmata recruits. About half of the retained tetrapods still harbor at least one healthy elkhorn coral, which have grown to sizes ranging from 5 to 10 centimeters in diameter. Some are starting to form their first branches. “It is rewarding to see that the outplants are doing so well. In another two years, the colonies will reach sexual maturity and be capable of spawning themselves,” says Restoration Technician Kelly Latijnhouwers.
Overall, these young elkhorn coral colonies are looking very healthy at all outplanting sites, which also include degraded reef locations. “This is the first proof of long-term success for our in situ rearing. Our teams and partners in Mexico, the Bahamas, and Curaçao are working in concert to keep improving the design of these ‘pools’, which allows the mass production of sexual coral settlers for large-scale reef restoration,” says Dr. Dirk Petersen, SECORE Founder and Executive Director.
1.7-year old Acropora palmata recruit on the breakwall in front of the Curaçao Sea Aquarium with the tetrapod barely visible underneath. The coral is now growing onto the natural substrate. (Kelly Latijnhouwers)
We could not have done this research and restoration work without the invaluable on-site support of CARMABI Marine Research Station and the Curaçao Sea Aquarium. Further sponsors and supporters of our reef restoration project in Curaçao are the California Academy of Sciences, the Columbus Zoo and Aquarium, Omaha’s Henry Doorly Zoo & Aquarium, the Nature Conservancy, the Clyde & Conny Woodburn Foundation, the Green Foundation, the Montei Foundation, TUI Cruises, the Penn State University, and the Virginia Aquarium and Marine Science Center Foundation. Thanks to all of them for their continuous support.
Acropora palmata recruit starting to develop a three-dimensional structure - an important step towards restoring structural complexity. The colony will soon start forming its first branches and will be capable of spawning, itself, in just 2 more years. (Kelly Latijnhouwers)
Text: Kelly Latjinhouwers