Captive coral can be bred on demand

Researchers from the Australian Institute of Marine Science (AIMS) have announced they have successfully bred the next generation of captive-raised corals in an experimental aquarium outside of their natural reproductive window, months before the annual spawning season which normally takes place on the Great Barrier Reef over a handful of nights in November or December.

Guided by environmental cues such as temperature, day length and moon phase, corals along the length of the Great Barrier Reef will release eggs and sperm into the water, to create new coral larvae. Researchers at AIMS’s National Sea Simulator (SeaSim) in Townsville have now replicated the same environmental conditions that prompt spawning on the Reef and applied them to captive corals from six species reared at the facility since 2014.

“These corals have never been exposed to natural environmental cues — they have been raised under artificial conditions all their lives,” said Lonidas Koukoumaftsis, a senior aquarist at SeaSim.

The research technicians induced 43 corals from the six species to spawn months before the normal spawning season, and four hours earlier in a typical spawning evening. The team’s success continued when the egg and sperm bundles fertilised and the larvae settled and grew to become young corals, closing the life cycle in captivity for four of the six coral species.

“By using the advanced capability of the SeaSim facility, we were able to manipulate the seasonal cues that corals use to spawn,” said senior technical officer Matthew Salmon. “It is incredible to be involved in this groundbreaking achievement.”

AIMS benthic and restoration ecologist Dr Carly Randall said the ability to control the timing of corals’ reproductive cycle was key to bypassing the bottleneck of seasonal larval supply, with implications for both coral aquaculture and research applications.

“The ability to obtain coral larvae multiple times a year allows scientists to undertake research that is critically needed to determine how best to help reefs recover from disturbances,” she said. Currently researchers have only one window of opportunity per year to capitalise on the spawning to research issues vital to the future of the Great Barrier Reef, so multiple spawning events would help fast-track knowledge development around coral biology.

“The ability to control the timing and frequency of spawning in the lab increases research opportunities to stay ahead of the curve and accelerate the development of feasible options to protect the Great Barrier Reef from some of the effects of climate change,” Randall said.

“If marine science and research can delay coral decline by 20 years, we have created a significant window of opportunity for climate adaptation measures to produce solutions and for global initiatives to curb emissions.”

Image ©Marie Roman/AIMS.

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