COTSBot



Anya Sikri



Can you imagine that starfish could be the reason that the Great Barrier Reef has lost most of its’ corals? Well, it’s true. The Crown of Thorns Starfish is responsible for ruining 40% of the Great Barrier Reef.


The starfish can grow up to 30 inches in diameter and they have 20 arms covered with long spines. Each of the spines are coated with a toxin that can be very painful if it comes into contact with human skin. The Crown of Thorns Starfish can produce up to 60 million eggs in a season, and a single starfish can eat 13 square meters of coral per year. That’s 780 million square meters of coral eaten by starfish per year!


The Crown-of-Thorns Starfish feeds on hard coral with skeletons called polyps. It spreads its’ stomach out through the mouth over living coral, releasing digestive juices, it kills the coral and after feeding on the starfish it moves on leaving a patch of white, the coral’s skeleton.


The only way to kill the COTS (Crown of Thorns Starfish) was to take it out of the water and inject it 20 times with Sodium Bisulfate, to kill it. Recently, researchers have found a way to kill it with a single shot without affecting the other animals in the area. However, it would still take a lot of time for divers to inject 60 million starfish. Then, Dunbabin and Feras Dayoub, from the Queensland University of Technology, invented a robot that can kill the COTS easier. They named it the COTSbot; it works 8 hours a day, and can kill up to 200 starfish in a single dive.


The robot has stereoscopic cameras to give it depth perception, five thrusters to maintain stability, GPS, pitch-and-roll sensors that measure altitude, and a unique injection arm to deliver the injection. The COTSbot becomes a real force multiplier for the process of killing the starfish. Imagine how much ground the programs could cover with 10-100 COTSbots.


Key to the underwater vehicle is its state-of-the-art computer vision and machine learning system. Roboticists have spent the last six months developing and training the robot to recognise COTS among coral, using thousands of images of the reef and videos taken by divers. Dr Feras Dayoub, who designed the COTS-detecting software, said:


"Its computer system is backed by computational power so the COTSbot can think for itself in the water. If the robot is unsure that something is actually a COTS, it takes a photo of the object to be later verified by a human, and that human feedback is incorporated into the robot's memory bank.”


The researchers have now trained the robot using thousands of images of the Crown of Thorns Starfish collected on the reef, and the robot is proving itself incredibly well at detecting the starfish. The COTSbot is the first self moving underwater vehicle to have an injection system.


Bibliography

http://www.popsci.com/robot-kills-starfish-released-on-australian-reefs http://oceanbites.org/lethal-injection-cots-ed/ https://www.divingcairns.com.au/reef_crownofthorns http://www.eoearth.org/view/article/151544/ http://www.azula.com/crown-of-thorns-starfish-coral/

http://www.azula.com/crown-of-thorns-starfish-coral/ http://www.usnews.com/news/articles/2012/10/01/study-great-barrier-reef-has-lost-half-its-coral https://www.qut.edu.au/news/news?news-id=95438