Researchers Use AUVs to Control Crown-of-Thorns Population in the Great Barrier Reef

The Great Barrier Reef is the world's most extensive coral reef ecosystem located on Australia's north-east coast. According to UNESCO, the Great Barrier Reef housed over 400 types of coral, 1,500 species of fish, and 4,000 types of mollusk.

With its great treasures, it is disappointing that it is slowly declining over the past decades due to various reasons, like climate change and the predatory starfish known as crown-of-thorns (COTS).

These COTS has wreaked havoc on 50% of the Great Barrier Reef in the past years by eating coral polyps that reside inside the coral reefs and effectively destroying them. But environmentalists have found a way to control them by using automated underwater vehicles (AUVs) called the COTSbot that injects lethal bile dose to the COTS.

COTS Eating Their Way Through The Great Barrier Reef

In 2018, ABC News reported that thousands of crown-of-thorns are eating their way throughout the Great Barrier Reef in what is considered to be a major outbreak in its southern part.

According to the Great Barrier Reef Marine Park Authority (GBRMPA), authorities have been monitoring and working out ways to deal with the outbreak, such as preemptive culling of some corals.

Environmentalists have been tackling the problem of COTS in the Great Barrier Reef for many years. But they are not always a problem.

In normal numbers on healthy coral reefs, COTS can be helpful as they tend to eat the faster-growing corals to give way for slower-growing corals to catch up and therefore enhance the coral diversity in the reefs, according to the Great Barrier Reef Foundation.

However, too much of them on the corals adversely impact the reefs. A 2017 study suggests that the presence of too many COTS in the reef is and tropical cyclones are the two leading causes of coral cover loss in the past 27 years.

But today, researchers are using automated underwater vehicles (AUVs) called the COTSbot to control the population of COTS and prevent further harming the Great Barrier Reef.

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COTSbot to the Rescue

Researchers at Deakin University and Murdoch University in Australia and the Azad University of Khoemeinishar in Iran have used AUVs to investigate the propagation of COTS and the possibility of managing them.

In a paper published on arXiv, the researchers presented the approach of using COTSbots to allow multiple AUVs to communicate with each other to cooperate in monitoring and controlling the COTS in the Great Barrier Reef to prevent further damage.

According to TechXplore, COTSbots are unique underwater robotic systems developed at Queensland University of Technology (QUT) that have cameras, a computer vision system, and a foldable robotic arm with a long needle at the end.

The robot uses its GPS and cameras to navigate through the Great Barrier Reef as it collects images that are analyzed by an AI trained to detect the presence of the thorny starfish. When it detects the COTS, it will then inject it with the lethal bile salt using the needle attached at the end of its robotic arm.

Furthermore, the researchers also designed a probabilistic map of the surroundings that the COTSbots would be operating in and developed the Heuristic Feel Cooperation (HFC) algorithm to allow the collaboration between the COTSbot in exterminating as many COTS as possible within a given time.

Ultimately, the researchers hope that they could use the framework they came up with to eradicate and monitor clusters of COTS that threatens the survival of the Great Barrier Reef.