Rare coral species bred and raised in lab

In a first, researchers have successfully bred and raised in the lab a rare and threatened Caribbean coral species.

The study, published in the open access journal BMC Ecology, could provide information to help bolster local coral reef conservation.

"Now that we've successfully reared juvenile Pillar Corals in the lab, not only can we study them in more detail to find out what factors could be threatening their survival in the wild, but it also means that we can try to out-plant a small number back to the reef," said lead author Kristen Marhaver from the CARMABI Foundation on the Caribbean island of Curacao.

The Caribbean Pillar Coral Dendrogyra cylindrus is rare and understudied, and small juveniles of this species have never been seen in over 30 years of surveys in the Caribbean.

"We do not know if this will work and it is certainly not a cure-all for the reef. But especially in such a rare coral species, a tiny boost of a few new individuals could make a big difference in their genetic diversity, allowing their populations to adapt and become more resilient to the changing environment in the oceans," Marhave said.

The species is one of very few corals in the Caribbean that forms large branches, which can provide shelter for important fish species and reduce the energy of storm surge as it approaches shore.

After studying sunset times and lunar cycles taken from other spawning observations, the research team timed their egg and sperm collection around the most likely annual spawning times - exactly three nights after the August full moon and around 100 minutes after sunset.

In the lab, the team carefully adjusted several factors related to fertilisation times and seawater type and nurtured the eggs to develop into larvae.

They managed to successfully grow the embryos to the swimming larvae stage - the first time this has ever been seen - and settled them onto ceramic tripods in water tanks. The settled juveniles then survived for over seven months.