Scientists at Mote Marine Laboratory in Sarasota are celebrating a milestone. They bred smooth flower coral — one of the most difficult coral species to spawn in captivity.
Mote scientists rescued the species off the Florida reef two years ago and spawned them under controlled conditions.
Mote biologist Cody Englesma says this is a key way to insure smooth flower coral can survive in the wild.
“We're actually increasing the diversity of the corals that are going back to the reef. So the offspring are going to have traits that hopefully have a mix of their parents that are surviving in the wild,” he said. “So hopefully they're more temperature resilient. They've survived a few different diseases and storms. So hopefully their offspring should be a little bit more robust.”
He says they'll transplant the larvae back to the reef off South Florida once water temperatures cool down.
"For some reason, this species has just always been notoriously hard for other practitioners to keep in their aquariums," Englesma said. "And so not only having these corals spawn, but also rearing their recruits up into the stage that they would spawn as well is super awesome and kind of crazy."
He says they're increasing the diversity of the corals that are going back to the reef. So their offspring should hopefully be more resilient to heat and better able to survive in the wild.
"The reproduction isn't necessarily the hard part," he explained. "It's once they start reproducing, we get the coral larvae, which that's the free living stage of the coral. And so once that is released, that has to find a place to settle on the reef, which would then live there forever. And so getting that larvae to settle where we want and to survive long term is really difficult for some reason."
Englesma said 90% of the coral off of South Florida has been lost. They are particularly susceptible to stony coral tissue loss disease. Another problem, he said, is it's hard for them to reproduce because the survivors are so far apart.
"Because of the state of our reefs, our corals are so few and far between that sexual reproduction isn't successfully happening. There's too few corals," he said. "It's a big numbers game when spawning comes into play where they're just putting a bunch of gametes out there. Fish are eating those gametes. And so now we're talking about fewer corals. The corals are far apart. Fertilization isn't happening.
"So Mote goes in there, we collect these gametes, we do fertilization, we see better fertilization rates, we see better settlement and survival rates. So, instead of getting one in a million larvae, we're getting thousands upon thousands to survive until the size that we can plant them."
The work is being done at Mote’s International Coral Gene Bank, located at the Mote Aquaculture Research Park in eastern Sarasota County. Over the last two years, the Gene Bank has raised the coral and helped the spawning of a second generation.
Here's some information on the gene bank from Mote:
The Gene Bank acts as a sanctuary for corals from Florida’s Coral Reef and other Caribbean regions, with future plans for expansion into the Indo-Pacific. The Gene Bank houses thousands of coral genotypes (genetic varieties) of at least 26 species stored in triplicate, offering a safeguard against the loss of coral genetic diversity.
Smooth flower coral remains notoriously difficult to settle. To encourage settlement, conditioned plugs are used and coated with bacterial films and a specific type of algae called crustose coralline. The species’ highly selective nature and the specific conditions required for settlement result in particularly low success rates. This makes the Gene Bank’s recent feat all the more significant.
The achievement of settling second-generation smooth flower coral within managed care holds immense potential for advancing coral research and restoration efforts as it has demonstrated the ability to reach reproductive maturity at a significantly smaller size and much younger age compared to most other coral species commonly used for restoration.
While many boulder coral species found in Florida may require over ten years to grow large enough to spawn, smooth flower coral has shown the remarkable ability to spawn within just two years. This accelerated reproductive cycle is potentially crucial in the face of rapidly changing environmental conditions, such as rising ocean temperatures and increasing disease prevalence, as it may promote faster rates of adaptation through time. The ability to adapt to these changing conditions will be vital as coral reefs face ongoing degradation worldwide.
Additionally, by incorporating smooth flower coral into restoration programs, scientists can enhance the community diversity and resilience of reef ecosystems, thereby improving the long-term efficacy of reef recovery.
