Lionfish-killing robot in development

A lionfish between two culling paddles during tests of a prototype of a robot designed to electrocute the invasive species.

John Rizzi’s company is building a prototype robot designed to electrocute lionfish – and then collect the corpses for consumption or research. Tests are scheduled to start next month.

Mr. Rizzi is executive director of RISE – Robots in Service of the Environment – which is taking a new approach to combatting exploding lionfish populations throughout the Atlantic and Caribbean seas. He hopes to have an initial test unit in the water by late November/early December, and to have an operational model by the following June.

“We’ll do two or three trips to Florida, while a lot of the [development] work will be done in the shop,” he said.

Essentially, the machine comprises a small underwater platform guided by two operators working from a boat. The platform, a remotely operated vehicle, features two metal plates or paddles, which function as electrodes. Raised and lowered by radio signals to the ROV, they descend on either side of the target fish.

The operators throw a switch, triggering a modest current between the two plates and electrocuting the animal. A second mechanism collects the corpse.

This rendering of the Harvester Prototype Lionfish Hunter by Robots in Service of the Environment, or RISE, shows how a robot arm with two metal electrodes on the end could electrocute invasive lionfish. The deceased fish would then be collected in a central chamber.
This rendering of the Harvester Prototype Lionfish Hunter by Robots in Service of the Environment, or RISE, shows how a robot arm with two metal electrodes on the end could electrocute invasive lionfish. The deceased fish would then be collected in a central chamber.

Lionfish have no known predators, so they are largely impervious to fear and remain still as the paddles appear on either side of them.

“We are building an ROV now for our own experience,” Mr. Rizzi said. “It’s almost like a video game.”

He acknowledges that lionfish populations have spiraled nearly out of control up and down the U.S. east coast and throughout the warm Caribbean waters.

Mr. Rizzi’s first experience with the invasive species was through Colin Angle, iRobot’s CEO and designer of RISE’s remotely operated vehicle and its capture mechanism, control and vision systems. Mr. Angle was on a dive trip to Bermuda when he met local conservationists who asked for help in controlling the lionfish population. The ROV was the result.

Mr. Rizzi acknowledges that electrocuting lionfish one at a time is unlikely to effect control of the population, but is reluctant to use the term “extermination.”

“It’s only people that struggle with lionfish in places that are infested who really understand what is happening. We have to take a softer line – and we have to be realistic,” he said. “They are never going to be exterminated. They breed too quickly.”

Peter Quilliam, director of operations at Little Cayman’s Central Caribbean Marine Institute, says lionfish spawn at a rate of 40,000 eggs every couple of days, more than 1 million per year.

“It’s only people that struggle with lionfish in places that are infested who really understand what is happening. We have to take a softer line – and we have to be realistic. They are never going to be exterminated.”

He and Mr. Rizzi agree that local culling programs and competitive “derbies” staged by local divers offer the best alternative for the moment.

“They all do great job,” Mr. Rizzi said. “The ROV, however, can go deeper and stay longer than a diver,” addressing at least some of the problems.

“We remain open to anything,” Mr. Quilliam said, “but it’s very tricky to get that job done, and unless you can do better than culling, that remains the tried and tested way.”

Rizzi’s ROV mechanism is unlikely to be a silver bullet.

“I applaud the efforts,” Mr. Quilliam said, “but as far as applications, well, the reef structure is different here than in, say, the Bahamas. We have a drop off, the Bahamas is mostly sand.

“Getting down to the depths could make a huge difference,” he said, but he worries that reef damage might drive off other marine life, leaving lionfish unobstructed, “and that will have a devastating effect.”

Divers trained to capture lionfish, he said, “work really well, and proves we can control them with culling.”

Bradley Johnson, research officer at the Department of the Environment, remains guarded but open-minded about the RISE platform.

“There have been quite a few different ideas as to how to combat and control lionfish,” he said, emphasizing that “at depth” is the critical battleground.

Divers are unable to descend much more than 130 feet, he said, pointing to significant lionfish populations as deep as 1,500 feet.

The ROV, in theory, could be a great thing, he said, but he worries about the practical applications.

“What are the costs?” he asked, citing concerns about efficiency, development, value for money and even safely operating an electrocution device in saltwater.

Mr. Rizzi was unable to pinpoint costs, saying only that he recognizes an ROV has to be commercially viable, encouraging a range of consumers, and has to be commercially priced.

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2 COMMENTS

  1. I think that Mr. Rizzi is marketing his loin fish robot business , but is not saying in his marketing strategy how devastating these robots would be to the underwater environment after he sells a 100 to people that don’t know and don’t care how they are operated around the coral where the fish / lionfish habitate , and can’t these robots be used to get other fish that are not invasive ?

    I think he should be told to take his sales pitch somewhere else .

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  2. This looks very clever but it appears to require lionfish to stay between the two plates long enough for the operator to throw the switch.
    It’s been my experience that they tend to be quite skittish.
    They do stay fairly still when you try to spearfish them. But they learn quickly and if you miss them the first time it’s hard to get close enough the next time.

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