We had just published a post on the plight of Australia’s Green Sea Turtles when this additional story from “down under” crossed our desk. The Great Barrier Reef has been plagued by the crown-of-thorns for decades. One of the world’s largest and most voracious starfish, it loves to chow down on hard corals.
The crown-of-thorns gets its biblical name from the venomous thorn-like spines covering its upper body that provides predator protection. This starfish can be found in warm waters throughout the Indo-Pacific region, but is perhaps most connected with Australia where it has inflicted considerable damage on the Great Barrier Reef. It has been estimated that an individual crown-of-thorns can consume up to 6 square metres (65 sq ft) of living coral per year. (photo – AIMS)
Of the many challenges facing the Great Barrier Reef including global warming, coral bleaching, ocean acidification and cyclones what can be done to curb the crown-of -thorns. The Australian Institute of Marine Science thinks they are on to something.
Update: Celebrating The Year of the Reef
During 2018 we are celebrating The International Year of The Reef. Over the next six months we will increase the frequency of our articles on the world’s coral reef ecosystems. We will include current news on the health of reefs and the worldwide efforts to maintain and restore them. In addition, we will republish a variety of our past, but still very pertinent and helpful articles on coral reefs. Our hope is that this effort will focus more attention on these very important issues.
Crown-of-Thorns on the Menu!
It is well understood that the Pacific Triton (Charonia tritonis) also known as the “giant triton” has a sweet tooth for the crown-of-thorns, seemingly unaffected by its sharp spines and toxic venom. But this natural predator is rare having been over harvested for its meat and shell to the point of being a threatened species.
The triton is now protected however, the it can only consume several starfish a week and with the crown-of-thorns numbering in the millions it seems like an overwhelming task for the rare triton.
However, researchers at AIMS believe they can use other triton traits to trick the crown-of-thorns, especially the smell of the triton. Whenever a starfish gets a whiff of triton they flee and although a fleeing starfish does not move very fast, it is agitated and that might be enough.
“The chemical cues from the triton snail are highly influential when it comes to COTS behavior,” explains Dr. Mike Hall of AIMS. “We only need to introduce water that a triton has been sitting in to disperse a group of the starfish – they don’t even need to see it.”
Using the same theory as a mosquito coil to repel pesky insects, maybe the chemicals that simulate the scent of a triton can be used to disrupt the starfish during spawning aggregations and limit fertilization. This could be a huge help because the crown-of -thorns are notoriously productive, one female can release around 150 million eggs in a single spawning.
Work at AIMS continues, on isolating the chemistry of triton scent as well as finding ways to increase triton reproduction. This research offers hope in combatting the decades old problem of the crown-of-thorns.
by Robert Frerck, Blue Ocean Network
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