The crown-of-thorns starfish (Ancanthaster planci) is wreaking havoc on Australia’s Great Barrier Reef.
According to research by the Australian Institute of Marine Science, coral cover on surveyed reefs has declined by 50 percent in the past 30 years, and crown-of-thorns starfish were responsible for nearly half of the destruction.
As the Great Barrier Reef Marine Park Authority explains, crown-of-thorns can actually play a beneficial role in healthy reefs. They feed on the fastest growing corals, allowing slower growing coral to form colonies, which helps increase diversity.
But major outbreaks of the starfish have gotten worse in recent years, according to University of Queensland researchers.
Previous attempts to contain the pests, including a robot that lethally injects the starfish and sending divers to capture them by hand, are not effective enough to keep up with the fast-growing populations.
Now, husband-and-wife researchers Bernard and Sandie Degnan, of the University of Queensland, say they can use the “powers of attraction” to combat the reef’s enemy.
The Degnan’s and fellow University of Queensland researchers collaborated with colleagues at the Australian Institute of Marine Science, Okinawa Institute of Science and Technology and University of the Sunshine Coast.
They sequenced genomes of the starfish from Australia and Japan and were able to decode its pheromones, which the starfish uses to communicate and attract mates.
When pheromones are released, large groups of crown-of-thorns gather to spawn. Females can produce up to 120 million offspring in just one spawning season. The starfish typically spawn between October and February, and are native to coral reefs in the Indo-Pacific region.
The researchers believe they can use this discovery to exploit and capture the pests in larger numbers than current methods.
“Now we’ve found the genes the starfish use to communicate, we can begin fabricating environmentally safe baits that trick them into gathering in one place, making it easier to remove reproductively-primed animals,” said Bernard Degnan.
The starfish are so destructive because they eat hard coral – they type of coral responsible for building and growing reefs. This makes reefs even more vulnerable to storms and bleaching.
“What I like most is that we’re finding a solution to a problem, not merely documenting it,” said Degnan.
The researchers said this technique could be applied to other invasive marine pests throughout the world. Results of the study were published in Nature.
In addition to crown-of-thorns, the top two main causes of decline in the Great Barrier Reef are storms and coral bleaching.
Aerial footage released by James Cook University this week confirmed severe coral bleaching in the Great Barrier Reef for the second consecutive year. According to the JCU researchers, two-thirds of the reef—900 miles—have been impacted by these back-to-back bleaching events.