See more of the story

MIAMI – Not long after the August full moon, Florida’s reefs are the scene of an annual show of sexual reproduction called the coral spawn, with coral colonies releasing masses of tiny white, pink and orange spheres into the ocean.

This year, for the first time, corals raised by scientists in a lab and transplanted to the natural reefs are primed to join the spawn — a promising milestone for efforts to restore the ravaged reef systems off South Florida.

“This is really amazing because we had no idea what to expect when we planted these corals five years ago,” said Hanna Koch, a coral reproduction scientist at Mote Marine Laboratory, which is using microfragmentation-fusion to raise the corals on land and plant them on local reefs.

That technique is helping slow-growing corals such as the mountainous star to grow as much as 50 times faster than normal, she said. This year, scientists say the threatened species have achieved maturity and are primed with egg-sperm spheres called gametes.

Scientists from Australia to the Keys are racing to restore reefs as more frequent climate change, bleaching events, increased coastal development, pollution and overfishing are killing corals at an alarming rate.

The discovery of gametes, or an organism’s reproductive cells, on mountainous star corals that were planted just five years ago means that the use of macro fragmentation and fusion can help replenish depleted reefs faster, Koch said.

With this technique, researchers break large brain corals into microfragments, producing clones that grow in the lab. After a few months, they are planted onto the reefs. After a few years they begin to join together.

“We can grow large boulder corals to be about the size of a dinner plate within two or three years,” said Erin Muller, science director of the Elizabeth Moore International Center for Coral Reef Research and Restoration at Mote. “We know that this method is going to work for coral restoration.”