giving coral reefs a future

Project Coral started at the Horniman Museum and Gardens back in 2013 with the ambitious vision of curator Jamie Craggs “to better understand the drivers of coral reproduction and to develop protocols to facilitate predictable spawning events in captivity.” That is to purposefully induce coral spawning by simulating lunar and temperature cycles to mimic nature in an aquarium environment. “Broadcast corals spawn over just a few nights of the year and that presents considerable logistical challenges, particularly in closed aquarium systems”, explains Jamie. “The project is a journey of discovery and a great deal has been learned from both successes and failures which have shaped our collective knowledge. These have laid the foundations for this recent successful in-vitro fertilisation, opening up a whole new range of possibilities. We are excited about what the future holds!”

Nine coral colonies from two Acropora species (A. tenuis and A. millepora) released about 130,000 eggs during a spawning event last December:
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The purpose-built aquarium laboratories at the Horniman Museum and Gardens are microprocessor-controlled and offer the opportunity “to investigate the influences of the lunar cycle, diurnal changes, seasonal temperature changes, solar irradiation patterns and nutritional input on gamete (egg and sperm) production and release.” Fundamental for any scientific work on coral reproduction and early adaptation is to not let single corals spawn, but to simultaneously induce spawning in several specimens in order to enable cross-fertilization of corals and to follow the development of the resulting recruits.

Left) fresh egg-sperm bundles, center) the bundles break apart, separating sperm and eggs, and are ready to be fertilized. Right) the fertilized eggs start to grow and divide:
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“Small organization, big aims”, that is how Jamie described his ambitious project. Together with international partners, such as SECORE and S.E.A. Aquarium (Singapore), but with a small, nevertheless dedicated team at the museum, he achieved what many researchers have dreamed of.

And future plans are by no means smaller. We want “to use these protocols to further enhance our understanding of climate impact on coral reefs and to support reef restoration efforts to mitigate damage,” Jamie points out. We just started to learn about the impact of climate change on coral reef ecosystems and Jamie's work may play a great part to understand how coral will reproduce in the near future. The outcomes of such research may have profound implications for future coral restoration and coral conservation efforts. They will further help to use sexual reproduction as a tool for sustainable coral aquaculture.

Dirk Petersen (SECORE) adds: “The successful experiment at the Horniman Museum is a milestone and shows us again, once more, that public aquariums are important places for scientific research. With this knowledge and technology, a whole range of new research questions can now be addressed including the effects of climate change on coral reproduction.”

Top) growing coral colonies already visible with the naked eye, yet without their pigmented algae and bottom) after they gained their algal symbionts (pencil point for size comparison):

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all photos and video by Jamie Craggs, Horniman Museum and Gardens

by Carin Jantzen