A unique messaging system used by the crown-of-thorns starfish to 'talk' to each other could hold the key to saving the Great Barrier Reef from the marine predator's devastating attacks.
Australian and Japanese researchers uncovered the weakness after sequencing the starfish's genome as part of a project aimed at developing a bio-control for the coral killer.
The crown-of-thorns starfish (Acanthaster planci) is recognised as one of three major threats to the World Heritage-listed Great Barrier Reef, along with coral bleaching and damage through cyclones.
Lead researcher Professor Bernie Degnan, from the University of Queensland's School of Biological Sciences, said the crown-of-thorns could totally denude the reef of living coral during an outbreak.
"It depends on the density of the outbreak [but] under extreme cases you can have 150,000 animals in a square kilometre of the reef and some of these starfish get to half a metre in diameter," he said.
Professor Degnan said their research, published today in the journal Nature, was focused on using genomics and proteomics (the study of proteins) to find a potential solution to the crown-of-thorns problem.
As a starting point, Degnan and colleagues in Queensland and Okinawa, sequenced the genome of crown-of-thorns starfish from the Great Barrier Reef and Japan and the water-borne plumes released by the starfish during spawning season.
Professor Degnan said the crown-of-thorns starfish 'smelt' chemicals in the plume that they followed to the spawning site.
"These are the signals the other starfish recognise and migrate to," he said.
The researchers isolated the molecules in the seawater that were produced by the aggregating starfish and were able to then map these proteins back to the starfish genome.
"We can use those proteins to ... make baits or attractants that we can put in the field to attract crown-of-thorns and then harvest large numbers of animals on a big scale," Professor Degnan said.
Hopes for bio-control within five years
Professor Degnan said it was possible the team would have a bio-control ready within the next five years.
"It's not like curing cancer," he said. "It's a pretty straightforward thing ... we've demonstrated these plumes have some attractants now we have to test which of the factors are doing the job and how do we fabricate them into a bait that we can put in the ocean."
He said the control would be as "clean and green as you can imagine".
"So whatever we produce it won't be recognised by the rest of the animals in the ecosystem so it is completely environmentally benign."
Their research also showed the genome of the Japanese and Australian crown-of-thorns species were "remarkably similar".
This was important as it meant any bio-control developed either in Australia or Japan would be transferrable to both regions.
Professor Degnan said the same approach could also be used to control invasive starfish populations in Victoria and Tasmania, as well as other marine pests in freshwater and marine environments.
