We had an opportunity to attend a two-day Reef Renewal course at VIP Diving in Kralendijk, Bonaire. During this course, we learned, through hands-on lessons, how to grow coral. Our instructor, Sean Price, taught us how to clean, prune, and propagate staghorn corals. We had three dives focusing on cleaning the algae off the nurseries, dividing staghorn coral into fragments for propagation, and outplanting corals on the sanding flats of Sebastian reef. We completed three dives where we practiced these essential reef restoration techniques. Divers who complete this course can become registered volunteers with Reef Renewal Bonaire to support reef restoration and participate in future dives. 

Besides the fragment technique used to grow coral, we also learned about the RRFB program to sexually reproduce coral. The purpose of this technique is to harness natural processes to enhance the reef's genetic variability.  The method involves collecting sperm and eggs during nightly spawning events between July and October. Spawning is triggered by a combination of factors, including rising water temperature and the lunar cycle, and typically occurs a few nights after the full moon.  We had the pleasure of meeting the Reef Renewal Bonaire staff. Recently, RRFB partnered with SECORE International to improve coral larval propagation on Bonaire. SECORE, a nonprofit organization, specializes in assisted sexual reproduction to restore coral reefs. 

SECORE's sexual propagation process, also called "coral seeding," involves divers collecting sperm and eggs, known as spawn, from wild corals during natural spawning events. The gametes are fertilized in a lab to produce millions of genetically unique coral embryos. The developing coral larvae are raised in enclosures, sometimes on floating "coral cribs," until they're ready to settle. The larvae are settled onto specially designed substrates, known as "seeding units," which can be directly planted onto degraded reefs. These seeding units, capable of attaching themselves to the reef without extensive manual effort, are scattered across restoration sites. As they grow and mature, successful corals eventually become sexually mature and spawn again, aiding long-term reef recovery. 

This collaboration enables RRFB to collect coral eggs and sperm, fertilize them in a laboratory setting, rear the larvae, and then outplant them to the reef, thereby increasing the genetic diversity and resilience of the coral population. Everyone was excited about the successful spawning of brain coral gametes. We were fortunate to visit the Reef Renewal laboratory, where, with the help of ultraviolet light and yellow filters, we could see new coral polyps settling into the nooks and crannies of the ceramic star. These polyps fluoresced red and were about 1-2mm, or about 1/32 of an inch, in diameter; the doughnut shape was barely visible to the naked eye.  Jason Mirsopoulos, Coral Restoration Practitioner & Bioinformatics Specialist, explained that volunteers on the reef renewal team collected the gametes of a brain coral earlier in the month. They were not successful in the last two years. He believed that the corals may have been too stressed out to spawn due to the marine heatwave, which hit the reef later in the summer and fall of 2023 and persisted through 2024.