More than 700,000 coral larvae spawned this week — not in their native habitat of the ocean, but rather at the Florida Coral Rescue Center in Orlando, where researchers replicate that habitat with natural lighting conditions for coral breeding, based on the lunar cycle.
Generally, coral spawns occur about 9 to 10 days after a full moon, according to FCRC Supervisor Justin Zimmerman.
“It's really amazing to shut the lights off, turn all the flow off the aquariums, and watch these corals spawn within seconds of each other in the tanks,” Zimmerman said.
Coral reefs are one of the most biodiverse ecosystems on Earth. Zimmerman calls them the “rainforests of the sea.” They support about a quarter of all marine life, including many seafoods, and provide flood protection for coastal communities. And Florida’s 350-mile Coral Reef provides an estimated tourism value of more than $1 billion a year, according to the state’s environmental protection agency.
But coral reefs are in trouble, largely due to impacts from climate change.
Record-high ocean temperatures are driving the current global coral bleaching event, which has impacted 75% of coral reefs since January 1, 2023, according to the National Oceanic and Atmospheric Administration. Earlier this spring, the ocean got so hot that scientists reportedly hoped a few hurricanes might cool things off.
As the world's coral reefs dwindle, scientists are using different strategies to tackle the problem. Orlando's FCRC is a partnership between SeaWorld, Disney, the Fish & Wildlife Foundation of Florida and the Association of Zoos and Aquariums, all working together to restore some healthy coral to the sea.
It’s the kind of “Herculean task” that requires strong collaboration, said Disney Conservation Science Manager Andy Stamper.
“Believe it or not, corals are one of the most difficult animals to work with, from a husbandry and veterinary point of view,” Stamper said. “Trying to keep them alive and healthy takes a lot of resources: not only capital resources, but human resources and expertise.”
And caring for coral comes with another major challenge: scalability.
Bleaching makes coral more susceptible to deadly diseases like stony coral tissue loss (SCTLD), which in Florida has likely killed off millions of corals, according to the Florida Fish and Wildlife Conservation Commission.
“They're getting to the point right now where they're so few and far between, for a few species, there's a term called functionally extinct,” Zimmerman said. “Basically, they’re actually in the ocean still, but they’re not reproductive because their colonies are spaced out so far apart.”
That’s why the stakes are so high for coral restoration projects. And since coral species only spawn once a year – during specific, one-to-two month time frames — it’s extra important for researchers to get the timing right.
“We get one opportunity to collect the spawn from each coral,” Zimmerman said. “If we miss it, then basically we’ve wasted a year of waiting.”
Since the FCRC opened four years ago, researchers have seen spawning in 13 out of 18 total coral species, Zimmerman said. This week, three out of five coral species spawned; the other two will likely reproduce next month.
For corals, the warming oceans are “a one-two punch,” Stamper said. It’s not just about disease, but also ocean acidification, which happens when saltwater and carbon dioxide mix. As the ocean becomes more acidic, it weakens the corals’ skeletal structure.
That’s why restoring coral in itself is only the first step. The project’s “end game,” per Zimmerman, is to put as many corals back into the ocean as possible — but what if that new environment isn’t healthy for them?
“Not only do we have to figure out these technical hacks to try to get them to breed and get them back out in the wild, but we have to correct what's happening to them originally in the wild, and that has a lot to do with the carbon dioxide,” Stamper said.
Meanwhile, researchers are hoping to help the coral adapt to become more resilient to the impacts of warmer seas. The FCRC project focuses on sexually reproduced corals, Zimmerman said, which offer more genetic diversity than coral that is simply cloned, then replaced back into the ocean.
“It's one of the only chances I think there is of getting these corals that maybe are more tolerant to the ocean; more resilient to the pollution, the disease, the heating, back into the environment,” Zimmerman said.
The ongoing, global coral bleaching event is the fourth ever recorded by NOAA, and the worst one yet. But amid all the challenges, the FCRC team remains hopeful that ultimately, science will help some of the world’s coral reefs survive.
“If there’s any animal that can do it, corals can do it,” Stamper said.
Just like out in the wild, not all the coral larvae reproduced this week will ultimately survive. But this weekend, those that did will be moved to several different partner locations, where they’ll continue growing and, eventually, be planted out in the ocean.
“If people can work together, we can solve this,” Stamper said. “This is solvable. Just, people need to focus, and we do need to let science kind of lead the way.”
