In a ground-breaking study published in late September, scientists have mapped the reproductive strategies and life cycle of an endangered coral species, offering hope it can be saved from extinction.
Endemic to south-eastern Australia, the purple cauliflower soft coral Dendronephthya australis has experienced heavy losses over the past three years, having been decimated by shifts in sediment and La Niña flood events. It serves as vital habitat for other species, including the Endangered White’s seahorse and baby snapper.
Lead researcher, Southern Cross University PhD candidate Meryl Larkin employed a combination of methods to map the reproduction strategies and life cycle of the species, including histological analyses of fresh specimens, a 19-year collection of in situ images, as well as lab-based study in aquaria. She was conducting lab work at the Port Stephens Fisheries Institute when she observed, for the first time, eggs and sperm within coral fragments from different colonies, thus confirming the colonies as either male or female. Then, discovering the time at which female corals spawn, she devised IVF methods to produce larvae and, with some advice from coral biologists at the Australian Institute of Marine Science, managed to achieve larval settlement in the lab. Through this process, Ms Larkin became the first person to witness the single-polyp stage of baby corals for the species.
Coral babies produced in the lab were then successfully introduced back into the wild and have been growing well.
“This was a major step forward in the prospect of recovery by the species because, from just a few remaining colonies, we were able to produce hundreds of new individual corals,” Ms Larkin said. “Our discoveries open new doors for conservation strategies, including potential restoration efforts. It has given us real hope we can keep this coral off the extinction list.”
Read the paper at: https://link.springer.com/article/10.1007/s00227-023-04298-x
