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From the website Mother Nature Network:

Robots hunt starfish, lionfish to save coral reefs
Bryan Nelson
March 15, 2019, 11:19 a.m.

The robot apocalypse has arrived ... if you happen to be a crown-of thorns starfish or a lionfish.

Why target these poor, innocent starfish? Well, the truth is that they aren't so innocent. When crown-of-thorns starfish population densities are under control, these beautiful creatures play a balanced role in the ecosystem of the Great Barrier Reef. But when their population booms, they can quickly become a plague, consuming coral reefs — their favorite food — with a frenzied fervor.

Unfortunately, such population booms have been happening more and more frequently along the Great Barrier Reef over the last several decades. The problem has become so ubiquitous that scientists now believe that crown-of-thorns starfish are responsible for an estimated 40 percent of the Great Barrier Reef’s total decline in coral cover.

Queensland University of Technology researchers created a killer robot in 2016 with the singular purpose of seeking out and terminating crown-of-thorns starfish, reports Techie News.

The robot, called COTSbot (short for Crown-of-Thorns Starfish robot), is a Terminator-esque killing machine. It is designed to hunt down crown-of-thorns starfish and inject them with a lethal brew of bile salts. It is capable of diving for as long as eight hours in order to deliver its poisonous mixture to as many as 200 starfish. Equipped with stereoscopic cameras for depth perception, five thrusters for stability, GPS and pitch-and-roll sensors, as well as a unique pneumatic injection arm, it is an efficient executioner. The only thing missing is an audio track proclaiming "Hasta la vista, baby" each time it vanquishes a starfish.

A smaller and mightier robot

In 2018, the same team developed a smaller version of the COTSbot called the RangerBot. It is less expensive and more agile in the water. "RangerBot will be designed to stay underwater almost three times longer than a human diver, gather vastly more data, map expansive underwater areas at scales not previously possible, and operate in all conditions and all times of the day or night," the university said on its website.

Researchers hope that by releasing a fleet of COTSbots they might restore some balance to the fragile ecology of the Great Barrier Reef, which is already under threat from pollution, tourism, coastal development and global warming.

The bots are autonomous, meaning they are capable of acting independently. For this reason especially, researchers want to make sure they are intelligent enough to identify crown-of-thorns starfish accurately. The last thing the reef needs is a fleet of assassin machines indiscriminately killing the wrong starfish species or other creatures that are healthy contributors to the ecosystem.

The robots' advanced computer vision and learning algorithm allow it to learn to target crown-of-thorns starfish more accurately. If for any reason the system struggles to identify its target, it can also record images and send them to researchers for visual confirmation.

If they are successful, the hope is to use these robots in other reefs around the world.

"The systems software architecture has been developed with task expansion in mind," Matthew Dunbabin, a professor of electrical engineering and robotics at Queensland University of Technology, told the Daily Beast. "The system can be easily upgraded with new detection modules, similar to the way plugins in apps work, without the need to change hardware."

Hunting for lionfish

Another invasive species is the target for a different underwater robot.

The lionfish is a fast-growing voracious eater that reproduces year-round. It also has no known predators in the eastern Atlantic and Caribbean, so it threatens the health of coral reefs and other marine ecosystems.

The National Oceanic and Atmospheric Administration (NOAA) says lionfish "have become the poster child for invasive species issues in the western north Atlantic region."

A robot that is part tongs and part vacuum is the latest device built in attempts to curb the exploding population of lionfish in the Atlantic Ocean.

Colin Angle, inventor of the Roomba, has spent the past couple years fine-tuning his robot, The Guardian. He also established a nonprofit organization called Robots in Service of the Environment (RSE), to help save other marine life that are being decimated by the lionfish.

"Here, there is nothing stopping them," Adam Cantor, director of engineering for RSE told Environmental Monitor. "Local fish don’t see them as a threat and often swim close to them and are just readily gobbled up. No predator is willing to eat them, nothing is immune to their venom, and in the Atlantic, they are eating anything up to half their size."

The Guardian places "tongs" around the fish and shocks it with electricity. After the fish is stunned, it's sucked into a vacuum tube. The robot can hold several fish at a time and travel 200 to 500 feet below the water's surface. The organization is still conducting tests in the Bahamas and has not announced when the robot will be available for purchase.

Another method to capturing the elusive lionfish is the traditional fishing practice of spearing them. Students at Worcester Polytechnic Institute (WPI) in Massachusetts are developing autonomous robots designed to hunt for and harvest lionfish.

Although there are other robots that could be used to harvest lionfish, an operator must be connected to them by a tether, which could harm fragile reefs. The WPI robot would be untethered and would hunt for fish on its own, spearing lionfish and then sending them to the surface via a buoyant spear tip in order to be collected.

“The goal is to be able to toss the robot over the side of a boat and have it go down to the reef, plot out a course, and begin its search,” said Craig Putnam, senior instructor in computer science at WPI, in a statement. “It needs to set up a search pattern and fly along the reef, and not run into it, while looking for the lionfish. The idea is that the robots could be part of the environmental solution.”

Editor's note: This article has been updated since it was originally published in September 2015.