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"Talking Science" in August 2019 with the Coral Chronicles

Updated: Jul 31, 2019


As acroporid spawning season approaches in late August and early September, the CRF™ team is gearing up to make this another successful year for coral spawning. Corals have two main ways of reproducing: through fragmentation and through spawning. Once a year, shortly after the full moon, corals will release their gametes into the ocean, where they float to the surface and mix with other coral gametes to form coral larvae.

We are proud to say that our corals in our nurseries have been predictably spawning for the past couple of years! Spawning is extremely energetically costly, which means that our corals aren’t simply surviving, but are actually thriving. Having our corals spawn is a good indicator that our corals are growing successfully and staying healthy.

In the past, we used to prepare our boats and head out to the nursery in the middle of the night for up to a week collecting coral gametes. This year, however, to save resources and increase efficiency, we are collaborating with Keys Marine Lab (KML) to conduct our coral spawning on land.


Two to three days before the expected spawning week, we will be transferring 12 genotypes of staghorn and up to 6 genotypes of elkhorn to the land based tanks at KML. The corals will come from our brood stock corals, which means they have been growing for more than a year, completely untouched. These corals are much thicker and larger than the majority of our nursery corals, generally averaging around 50 cm in maximum diameter, making them more stable and mature for spawning.

With the assistance from the Florida Aquarium and Georgia Aquarium, we will take these corals in large coolers of water to the KML where they will acclimate in salt water tanks and be monitored for spawning. By conducting this process on land, it allows us to collect more gametes and avoid uncontrollable factors such as bad weather.


After spawning occurs, larvae will be transferred to the Center for Conservation at the Florida Aquarium (FLAQ) where the corals will be raised at their land-based facilities. Last year, FLAQ took coral gametes from our nursery and created new genotypes by breeding and crossing different corals together. They raised the coral larvae for the first eight months before returning them to the nursery. Since then, we have been raising them at Tavernier nursery where they have been growing and developing so quickly!


Collecting coral gametes is extremely important, especially in our current climate. Due to the abnormally far distances between coral colonies because of the degradation of the Florida Reef Tract over the past few decades, coral colonies can no longer meet gametes with neighboring colonies to make new genetic variations. This lack of genetic variation has caused coral reefs to lose genetic diversity. However, we hope that our spawning program will bring back more genetic diversity to ecosystem, creating a stronger and resilient reef.


This project would not be possible without our partners at Keys Marine Lab, University of South Florida/Florida Institute of Oceanography, Florida Aquarium, Georgia Aquarium, Nova Southeastern University, NOAA, SeaWorld, SEZARC, and the University of Florida. We thank you all for your participation and look forward to our continued collaboration!



Animals have three main methods of dealing with changing environments: migration, acclimation, or adaptation. As corals are sessile animals and can’t migrate easily, the best short-term option for corals to survive these changing waters is to acclimate. For a coral to acclimate they have to make individual changes physiologically or behaviorally in response to the changing environment. The more a coral’s exterior can change and adapt to its environment, the more likely the coral can survive future stressors.

CRF™ has been collaborating with Matz Indergard, a graduate student in Mathew Gilg’s Lab at the University of North Florida, to look at the phenotypic plasticity of some of our corals. Phenotypic plasticity is the ability of one genotype to produce more than one phenotype when exposed to different environments. As surface temperatures are expected to increase 1-4°C over the next 100 years (Hoegh-Guldberg et al. 2007, IPCC 2014), Matz is looking to answer the question: does prior heat stress increase the viability of outplanted coral at different depths in a restoration setting?

Matz is looking at what happens when corals are exposed to a short period of heat stress before being outplanted onto the reef. He is testing whether corals that have been exposed to the heat stress will be better equipped to deal with rising sea temperatures and not bleach as easily.

From his prior research, he found that in a lab setting, staghorn coral fragments treated with the heat stress survived longer than untreated individuals and the amount of plasticity differed by genotype. However, these results were not replicated in the field with the coral outplants. Matz is now checking if he is seeing similar results with other species of corals.

Presently, Matz is working with two species of coral, elkhorn coral (Acropora palmata) and mountainous star coral (Orbicella faveolata). He has outplanted these corals at three different reef sites in Key Largo; Carysfort Reef, North Dry Rocks, and Grecian Rocks. Matz has been monitoring the growth and survival of these corals for a little over a year and will continue to monitor them through the end of 2019.

Some key takeaways from his ongoing research include: coral is plastic in thermal tolerance, plasticity varies according to genotype, and shallower depth has a significant positive effect on transplant viability.

Matz’s research is extremely important in the light of our ever warming oceans as we look towards all of our options in the field for coral restoration. He was also our last speaker at our monthly Sips & Science event! If you're interested in learning more about his research, check out his presentation here!


"Talking Science" Editorial Intern

Originally from Santa Fe, New Mexico, Raquel fell in love with the ocean at a young age and decided to move to Florida to pursue her dreams of saving it. Raquel graduated in May 2018 from Stetson University in DeLand, Florida with a BS in Aquatic and Marine Biology. Raquel has been working with CRF since May 2018 and has worked as a general intern, the Dive Program Intern, and now as the Volunteer Program Intern. Raquel is excited to be a part of the CRF team and looks forward to learning more about coral restoration and living life here in paradise.

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