How a PhD candidate uses IVF to grow Coral babies to help save endangered species on the Great Barrier Reef

Southern Cross uni researcher Meryl Larkin grows coral babies in an effort to save an endangered coral species that grows in the temperate waters of NSW.

One of Meryl Larkin’s Dendronephthya australis coral “babies” which has reached adult size at 18 months old. Photo: Meryl Larkin

New research at Southern Cross University has revealed the reproduction secrets of an endangered temperate water coral species, opening the way for new strategies to save it.

SCU PhD candidate Meryl Larkin is the first to document the reproduction of Dendronephthya australis, a threatened coral species found in the oceans of southeastern Australia, particularly around Port Stephens in NSW.

The pinkish purple coral, resembling a cauliflower, can grow up to metre tall and is found near the coast in areas of sandy seabed where there is high current flow.

Historically the coral – which shelters other species including the endangered White’s seahorse and baby snapper – has existed in colony clusters in Port Stephens, however many of these have been lost over the past three years.

Ms Larkin’s work led to a paper titled A glimmer of hope for an Endangered temperate soft coral: the first observations of reproductive strategies and early life cycle of Dendronephthya australis, of which she is lead author and which is published this month in the journal Marine Biology.

Working at the Port Stephens Fisheries Institute Ms Larkin observed, for the first time, observe eggs and sperm in the coral fragments of different colonies, which confirmed that colonies formed by the species are either male or female.

Meryl Larkin

The observation are important because corals have complex reproductive lives which vary across species and sometimes within the same species. Reproduction can be both sexual and asexual and parents can be male and female, or hermaphroditic.

She also used IVF methods to obtain larvae and achieve settlement in the lab – settlement being the stage at which coral adheres to the place in which it will grow.

The coral babies which produced in the lab were then reintroduced to the wild, where they have grown well, some reaching adult size.

“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.

She believes her work can help wild populations to stay thriving and to create new colonies in areas where they previously lived but have disappeared.

Dendronephthya australis is one of 100 species that are listed by the federal government’s threatened species strategy.

Ms Larkin’s PhD project is jointly funded and supervised by Southern Cross University and the NSW Department of Primary Industries. Support has also come from the NSW Environmental Trust.