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Robots to the Rescue!

Machines may be the answer to stopping a lionfish invasion.

A quiet hunter glides through the water. It’s searching for a fish. It spots just what it’s looking for: a spiny, striped fish, called a lionfish. But the hunter isn’t an animal. It’s a robot—called the Guardian LF1—designed to catch lionfish.

These fish are naturally found in the Pacific and Indian oceans. However, in the 1980s, lionfish invaded the Atlantic Ocean and Caribbean Sea (see Lionfish Invaders map, below). The fish are an invasive species in these regions. They ended up in these areas because pet owners carelessly dumped unwanted lionfish into the ocean.

Over time, lionfish numbers grew. And that’s a problem. The fish might look beautiful, but scientists have found that they’re destructive to ocean life.

Fish Invader

The invading fish are now harming coral reefs in the Atlantic and Caribbean. Lionfish eat practically every smaller fish they come across, says John Rizzi of Robots in Service of the Environment (RSE). This organization created the Guardian LF1 to combat the lionfish invasion.

“Small fish keep coral healthy,” he says. “If you take away the fish, harmful algae that smaller fish eat grow on the coral and cause coral to die.” 

It’s difficult to reduce lionfish numbers for several reasons, explains Rizzi. The fish reproduce quickly, laying 50,000 eggs every three days. They also have venomous spines that keep predators from eating them. And lionfish live in deep waters, where human divers can’t go. That’s why engineers at RSE designed a robot able to travel to the deep sea to catch lionfish.

Lionfish Invaders

Lionfish were first spotted off the Florida coast in 1985. This map shows where they can be found in U.S. waters today.

Robot Fishing

Last April, the team tested a prototype robot in the Atlantic Ocean. To operate the Guardian, a person on a boat uses a handheld controller attached to the robot by a long cord. A camera on top of the robot allows the operator to search for lionfish on-screen, like playing a video game. Rear thrusters move the Guardian. Once it’s close to a lionfish, two probes at the front of the robot stun the fish with an electrical shock. A vacuum sucks the unconscious fish inside the robot’s hollow body. The Guardian brings its catch back to the surface for people to eat. “They taste delicious!” says Rizzi.

A stunned lionfish inside the Guardian robot

The team’s test was a success. Within only a few minutes of hunting, the robot caught its first lionfish.

Engineers at RSE are now designing a version that can hold more fish. And Rizzi says they plan to test the robots with commercial fishermen who might someday use the machines to catch lionfish to sell. He hopes the robots make lionfish a popular menu item at restaurants—and help to save Earth’s coral reefs.

Continue the Learning Journey
Be an Engineer!

Use these steps to design your very own robot. 

In the article you just read, a robot helps solve a problem. What problem would you want a robot to solve? Think about challenges in your daily life and design a robot to help you. Check out the slideshow “Be an Engineer!” for help with your design.

Eco Builder

Play a fun science game about ocean ecosystems and invasive species.

Play one round of the video game “Eco Builder.” How many days did you live? Keep playing to see how well you fight the lionfish invasion. Be sure to record how many days you live for each round! Convince a friend or family member to play the game and see how well they fight invasive lionfish.

The name lionfish combines two very different animals. What kind of fish could you create using two different animals? Make a detailed, colorful drawing of your creature. Be sure to give it a name and describe its unique traits and where it lives. Then share your creation with a friend or family member!

This article was written by Kathryn Free for Science Spin 3-6 magazine.

Image Credits: Courtesy of RST (Header); JIM MCMAHON/MAPMAN® (Sightings); KLETR/SHUTTERSTOCK.COM (Lionfish); COURTESY OF RSE (The Guardian)