MOVING IN: Predatory lionfish from halfway around the world are taking over the Atlantic.

REINHARD DIRSCHERL/WATERFRAME RM/GETTY IMAGES

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NGSS: Core Idea: LS2.C

CCSS: Reading Informational Text: 2

TEKS: 7.10A, 8.11B, E.4F

Lionfish Invasion!

Engineers, divers, and chefs team up to protect coastal waters from a fearsome predator

ESSENTIAL QUESTION: What might happen if a plant or animal species is introduced into a region where it’s not naturally found?

COURTESY OF RSE

GOING DEEP: The Guardian robot can reach depths divers can’t.

Last May, Adam Cantor and a team of fellow engineers headed out in a boat to do some fishing near a coral reef off the coast of Palmetto, Florida. But the group didn’t have any of the usual fishing poles, tackle boxes, or nets on board. What they did have was a small, canister-shaped robot called the Guardian LF1. Cantor, who works with the nonprofit group Robots in Service of the Environment, helped design the bot with one purpose in mind: to catch lionfish.

Lionfish normally live in the South Pacific and Indian oceans. But they began appearing in Florida’s waters in the 1980s. How did the animals end up halfway around the world? Scientists believe they were imported to the U.S. as pets: Their stunning stripes and spines make them popular aquarium fish. Some owners likely dumped the animals into the Atlantic when they no longer wanted them. Those few rogue lionfish soon spawned a full-blown invasion.

Last May, Adam Cantor and a team of fellow engineers headed out in a boat. They planned to do some fishing near a coral reef off the coast of Palmetto, Florida. But they didn’t have the usual fishing poles, tackle boxes, or nets on board. Instead, they had a small, canister-shaped robot called the Guardian LF1. Cantor works with the nonprofit group Robots in Service of the Environment. He helped design the bot for one purpose: to catch lionfish.

Normally, lionfish live in the South Pacific and Indian oceans. But they showed up in Florida’s waters in the 1980s. How did the animals end up halfway around the world? Scientists believe they were brought to the U.S. as pets. Lionfish have stunning stripes and spines. That makes them popular aquarium fish. Some owners probably dumped the animals into the Atlantic, because they no longer wanted them. Those few stray lionfish soon grew to large numbers.

They may look beautiful, but lionfish are fearsome predators with huge appetites. When they move into an area, they can become an invasive species, wiping out native fish populations. That includes those important to fishers and to tourists who visit coral reefs. And Florida isn’t the only place under threat. Today, lionfish can be found from New England all the way to coastal South America, as well as in the Gulf of Mexico (see Lionfish Locations).

Researchers like Cantor are working to find inventive ways to combat the lionfish problem. And they’re not alone. Divers, fishers, and chefs are helping too. Together, they hope to prevent these fishy invaders from taking over.

Lionfish may look beautiful, but they’re fierce predators with huge appetites. When they move into an area, they can become an invasive species. They wipe out local fish populations. Some of those fish are important to fishers and to tourists who visit coral reefs. And Florida isn’t the only place at risk. Today, lionfish are found from New England all the way to South America’s coasts. They’re even in the Gulf of Mexico (see Lionfish Locations).

Cantor and other researchers are working on the lionfish problem. They’re finding new ways to fight back. And they’re not alone. Divers, fishers, and chefs are helping too. Together, they hope to stop these fishy invaders from taking over.

UNWELCOME PREDATORS

Lionfish have been able to gain so much ground in the Atlantic in so little time because they’re the perfect invasive species, says Michelle Johnston. She works at the Flower Garden Banks National Marine Sanctuary on the coast of Texas. Johnson is an ecologist, studying the interactions between living things and their environment.

Lionfish can live just about anywhere in the ocean, whether it’s a coral reef, a shipwreck, or a seabed. And they reproduce quickly. Females can lay more than 2 million eggs each year. Scientists believe just 10 to 40 females gave rise to the entire population of Atlantic lionfish, currently numbering in the millions. Researchers learned this by studying the animals’ DNA. These molecules carry hereditary information.

Lionfish were able to spread far in the Atlantic in a short time. That’s because they’re the perfect invasive species, says Michelle Johnston. She works at the Flower Garden Banks National Marine Sanctuary on the coast of Texas. Johnston is an ecologist. This type of scientist studies the way living things and their environment affect each other.

Lionfish can live almost anywhere in the ocean. They’re at home at a coral reef, shipwreck, or seabed. And they reproduce quickly. Females can lay more than 2 million eggs each year. Lionfish in the Atlantic now number in the millions. Scientists believe all of these fish came from just 10 to 40 females. Researchers learned this by studying the animals’ DNA. These molecules carry hereditary information.

© FABIEN MICHENET/BIOSPHOTO

BIG APPETITE: Lionfish are voracious predators.

In their native home, lionfish have their own predators that keep their numbers in check. But in the Atlantic, sharks, barracuda, groupers, and eels that could eat lionfish steer clear of them. They’re deterred by the animals’ venomous spines, which deliver a painful sting. That’s given lionfish free rein to take over local ocean ecosystems they’ve invaded. When it comes to lionfish versus native predators, says Johnston, there’s no competition. “It is like someone coming into your home and kicking you out and eating all your food.”

Lionfish will eat almost any smaller-sized fish they come across, spreading their fins wide to corner their prey and then swallowing it whole. And they keep hunting even when their stomachs are full. A single lionfish can reduce the number of fish living on a reef by 80 percent in just five weeks. Reefs depend on small fish because they graze on aquatic plant-like organisms called algae. Without the fish, algae overgrow on coral and cause it to die.

Lionfish have their own predators in their native home. That keeps their numbers down. In the Atlantic, sharks, barracuda, groupers, and eels could eat lionfish. But these predators stay away from them. That’s because lionfish have venomous spines, and their sting is painful. So lionfish invade local ocean ecosystems and are free to take over. Local predators can’t compete with lionfish, says Johnston. “It is like someone coming into your home and kicking you out and eating all your food.”

Lionfish will eat almost any smaller fish they find. They spread their fins wide to corner their prey. Then they swallow it whole. And they keep hunting even when their stomachs are full. A single lionfish can wipe out many fish on a reef. It can reduce their numbers by 80 percent in just five weeks. Reefs need small fish. That’s because the fish eat plant-like organisms called algae that live in water. Without the fish, algae spread over coral and cause it to die.

ALEX MUSTARD/NATUREPL

GOTCHA! A diver carries a speared lionfish in the Caribbean.

FIGHTING BACK

For years, divers armed with spears have worked to rid shallow waters along the coasts of unwanted lionfish. Each year, dozens of places, including Florida, hold tournaments where teams of divers compete to catch the most lionfish. These events are the first line of defense against the animals. They can remove thousands of the invaders from local waters in a short time.

Lionfish, though, can evade these efforts by hiding at depths beyond the reach of divers. That’s why Cantor’s organization created the Guardian robot: to nab lionfish in the deep sea (see Robo-Hunter). A person on a boat guides the robot through the water using a handheld controller. “People are surprised by how easy it is to drive,” says Cantor.

For years, divers have been fighting the problem. They use spears to get rid of lionfish in shallow waters along the coasts. Dozens of places, including Florida, hold lionfish contests each year. Teams of divers compete to catch the most lionfish. These events are the biggest defense against the animals. They can remove thousands of lionfish from local waters in a short time.

But lionfish can hide in places too deep for divers to reach. That’s why Cantor’s organization built the Guardian robot. It can catch lionfish in the deep sea (see Robo-Hunter). A person on a boat uses a handheld controller to steer the robot through the water. “People are surprised by how easy it is to drive,” says Cantor.

A camera on top of the robot provides the Guardian’s operator with an underwater view. Once a lionfish is in front of the robot, the operator presses a button. It sends an electric current from two stick-like probes at the front of the robot. The jolt stuns the fish. The press of another button triggers a vacuum that sucks the fish into the robot’s main chamber. The operator then steers the Guardian back to the surface with its catch.

The robot has a camera on top. This gives the Guardian’s driver an underwater view. When a lionfish is in front of the robot, the driver presses a button. Two stick-like probes are at the front of the robot. The button sends an electric current from the probes. The jolt stuns the fish. The driver presses another button, and a vacuum sucks the fish into the robot’s main chamber. Then the driver steers the Guardian back to the surface with its catch.

EATING THE ENEMY

During Cantor’s fishing expedition last year, his team was testing a prototype of the Guardian. The test model successfully snagged its first lionfish in open water. Since then, the group has continued to improve the robot to make it more effective and easier to use.

Cantor’s fishing trip last year had a goal. His team was testing a prototype of the Guardian. The test model caught its first lionfish in open water. Since then, the group has continued to improve the robot. They’re making it more effective and easier to use.

ALEX MUSTARD/NATUREPL

HEFTY HAUL: Divers caught these lionfish during a single day in the Cayman Islands.

The next phase of the project aims to enlist fishers to use Guardians to catch lionfish. They could then sell their haul to hundreds of restaurants that have added lionfish to the menu. Even though lionfish have venomous spines, their flesh isn’t dangerous to eat. “Lionfish are delicious,” says Johnston. “And they’re the most sustainable fish you can order on a menu.”

The group needs help from fishers for the next part of the project. Fishers could use Guardians to catch lionfish. Then they could sell their catch to restaurants. Hundreds of restaurants have added lionfish to the menu. Lionfish have venomous spines, but their flesh is safe to eat. “Lionfish are delicious,” says Johnston. “And they’re the most sustainable fish you can order on a menu.”

SUE DALY/NATUREPL

TASTY TREAT: Lionfish with butter and garlic at a restaurant on the Caribbean island of Bonaire

Cantor estimates that it would take about 1,000 Guardian robots to reduce the lionfish population enough to have a positive effect on a local ecosystem. Unfortunately, it’s unlikely this and other methods will completely eradicate lionfish from the Atlantic. “They’re so deep and so spread out,” says Johnston. However, she’s hopeful native predators will eventually acquire a taste for the fish, further reducing their numbers.

“We have to give it some time,” she says.

Many lionfish would have to be removed to have a positive effect on a local ecosystem. Cantor thinks that it would take about 1,000 Guardian robots to do this. But robots and other methods probably won’t remove all lionfish from the Atlantic. “They’re so deep and so spread out,” says Johnston. But she has another hope. Over time, local predators could start to eat lionfish. That would reduce lionfish numbers even more.

“We have to give it some time,” she says.

CORE QUESTION: Why are lionfish harmful to ecosystems in the Atlantic but not in the South Pacific and Indian oceans? Support your answer with evidence from the article.

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