Harpoon-throwing robot takes invasive lionfish from ocean to table

The lionfish is a beautiful but invasive species in the Gulf of Mexico, the eastern United States and Bermuda. Native to the South Pacific and Indian oceans, the species has found its way into the Gulf and Atlantic Ocean via tropical pet owners who dump the lionfish there. And because it has few known predators and hunts algae-eating fish that sustain coral reefs, the species poses a significant danger to the reefs’ survival.

The scale of the problem

Gavin Hunter, CEO of Atlantic Lionshare, recently told NPR that determining the scale of the lionfish problem is difficult. “Counting fish is an impossible task,” he said. “A single female lionfish lays up to 3 million eggs in a year; we’ve got no way of determining exactly how many reach maturity, so it’s a big guess,” although he estimated that the population is doubling every year.

“They are doing really well there at the expense of the native fish populations,” Casey Benkwitt, a marine biologist at Lancaster University, told Popular Science. The publication cited one report showing that a single lionfish can reduce the diversity of a coral reef community by 79%.

Because the species are deft at avoiding lures and nets, “You really have to just kill them,” Benkwitt told Popular Science.

New robot to the rescue

Because the species can live as deep as 1,000 feet, Bermuda-based Atlantic Lionshare has developed a robotic vehicle (a remotely operated vehicle or ROV) called the Reef Sweeper that’s designed to capture lionfish by spearing them.

“We operate it from our boats, and it actually spears the lionfish,” Hunter told NPR. “The lionfish have no sense of predators because they don’t have any natural predators.”

About the size of a refrigerator, the vehicle moves like a submarine, spearing the lionfish and capturing it in a holding cage until the Reef Sweeper is full and returns to the boat with its catch.

Popular Science reports that:

Right now Florida is testing one reef sweeper prototype with a kill capacity of 150 fish per trip. But Gavin Hunter of Atlantic Lionshare, which collaborated with the state to develop this technology, says that the company is working on rolling out a sleeker, more advanced prototype this summer. While the new model will only hold 70 to 100 carcasses, its spear can reload every 10 seconds, cutting down the time it takes to deploy the machine. Ultimately, Hunter says the goal is to have each ROV bag 1,000 lionfish a day.

Hunter told the publication that his company intends to deploy hundreds of Reef Sweepers at the cost of around $300,000 a pop.

Fortunately, lionfish are very tasty

“Nutritionally, they’re one of the best fish in the sea because they’re eating the juveniles of most of their prey,” and juvenile fish don’t contain as much of the toxic substances found in adult prey fish, Hunter told NPR. That means that the live lionfish captured are sushi-grade fish and can be sold as such, to consumers through Whole Foods Markets or directly to restaurants.

Hunter noted that there’s a healthy culinary demand for lionfish: “The value is in the nutrition” he told Popular Science. Once its spines are removed, the species serves as a flaky grouper-like fish and Hunter is selling them directly to restaurants and to Whole Foods Market for consumers. Hunter added that, at a current price of up to $6 a pound, there is an incentive for fishers to invest in a spear-throwing robot.

As he told Popular Science, “If you catch 100, it’s no good to anyone. If you catch 100,000, people are then able to put it on menus and into grocery stores.”

We are entering a new era of environmental innovation that is driving better alignment between technology and environmental goals — and results. #FourthWave

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The Fourth Wave

Environmental progress doesn't just happen. It's been propelled by successive waves of innovation, each unleashing powerful new tools: Land conservation. Force of Law. Power of Market-Based Solutions. Today we are seeing the emergence of a Fourth Wave of environmental innovation.

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