Vampire of the Deep

Eleven-year-old Beatrice Mertz held a slimy, slithering creature in her hand. It was as long as her forearm, and it had a round mouth lined with more than 100 razor-sharp teeth. It looked like an eel or a snake. But it was actually a fish—and it was her job to kill it.

With one quick motion, Beatrice cut the creature’s head off with a sharp knife. She breathed a sigh of relief.

The year was 1941. Beatrice had been working summers on her mom’s fishing boat on Lake Huron in Michigan. It is one of the largest lakes in the world and one of the five Great Lakes between Canada and the United States. Beatrice’s job was to get rid of the sea lampreys, a species of fish not naturally found in the Great Lakes. Like a vampire in a horror film, lampreys attach themselves to other fish, drill a hole into their flesh, and suck their blood. The creatures were killing the fish Beatrice’s mom was trying to catch.

“When a fish came into the boat and there was a lamprey on it, my mom would always say, ‘Beatsie, you take care of that lamprey!’ ” Beatrice remembers. “She would never allow a live lamprey to go back into the water.”

At the time, sea lampreys were spreading across all of the Great Lakes. Soon, these monstrous creatures would have a devastating impact on the environment.

Could anything be done to stop them?

Eleven-year-old Beatrice Mertz held a wet, wiggling creature in her hand. It stretched from her fingers to her elbow. It had a round mouth with more than 100 super-sharp teeth. It looked like a snake. But it was really a fish. And it was her job to kill it.

Quickly, Beatrice cut the creature’s head off with a sharp knife. What a relief, she thought.

The year was 1941. Beatrice had been working summers on her mom’s fishing boat. They fished on Lake Huron in the state of Michigan. Lake Huron is one of the largest lakes in the world. It’s one of the five Great Lakes between Canada and the United States.

Beatrice’s job was to get rid of the sea lampreys. That’s a species of fish not naturally found in the Great Lakes. Like a vampire in a horror film, lampreys attach themselves to other fish. They drill a hole into the fish’s flesh. They suck their blood. The creatures were killing the fish Beatrice’s mom was trying to catch.

At the time, sea lampreys were spreading across all of the Great Lakes. Soon, these awful creatures would have a terrible effect on nature.

Could anything stop them?

Sea lampreys are naturally found along the Atlantic Ocean’s coast. But the Great Lakes are far from the ocean.

So how did the sea lampreys get there? Scientists blame humans. That’s often the case with invasive species. These are plants or animals that are brought to a new place. Then they damage the species already living there. Many invasive species were brought to the U.S. as pets. Others arrived by mistake, hiding inside soil or boats.

Many scientists think that sea lampreys invaded the Great Lakes through the Erie Canal. This human-made waterway was built between 1817 and 1825. It allowed boats to sail from New York all the way to the Great Lakes—in just 10 days. Before that, the trip would take weeks!

Suddenly, people and goods could move quickly and cheaply between the East Coast and the Midwest. Towns thrived along the canal. The new waterway opened the door to business. But it also opened the door to sea lampreys. The fish traveled from the ocean into Lake Ontario.

The Great Lakes are all connected like a giant river. The water from one lake flows into the other. From Lake Ontario, sea lampreys spread into Lake Erie. Then they swam into Lake Huron and Lake Michigan. Finally, they reached Lake Superior.

In the Great Lakes, sea lampreys started an ecological disaster. The fish have adapted over millions of years to be skilled bloodsucking machines. The lamprey’s mouth is like a toothy suction cup. It grips the skin of its victim and doesn’t let go. Its tongue is like a sharp beak that cuts through fish skin. Lampreys even force special substances into their victims’ bodies to keep their blood flowing.

In the ocean, sea lampreys aren’t a problem. They attack large fish that can survive the blood sucking. And predators like swordfish keep their numbers down. But in the Great Lakes, the lampreys have no natural predators. The fish are smaller than those in the ocean. A lamprey attack often means death.

The number of sea lampreys in the Great Lakes rose quickly. They decimated fish like lake trout and lake whitefish. People who fished for a living, like Beatrice’s mom, were the first to notice. More and more fish caught in nets had lampreys on them. Or they had bloody wounds—the sign of a lamprey attack.

“My mom just kind of accepted it,” Beatrice says. But fishing was at the heart of the Great Lakes business and way of life. Without fish, thousands of people would lose their jobs. They wouldn’t have money to put food on the table.

Something needed to be done—fast.

Scientists quickly got to work. They tried shocking the bloodsucking fish with electricity. They tried trapping them in nets. They even tried cooking them! Unfortunately, the lampreys’ looks and smell turned diners off.

Meanwhile, scientists started testing poisons that could kill baby lampreys—without hurting other fish. As babies, lampreys live in rivers. Scientists hoped that the poison would kill baby lampreys before they swam from the rivers to the lakes.

Finally in 1956, after years of experiments, they identified a promising substance. The next year, they carefully put it in a creek in Michigan. The creek had been infested with lampreys. Within minutes, thousands of the creatures floated to the surface—dead.

It seemed like a solution had been found at last.

Today, more than 4,000 invasive species live in the U.S. Sea lampreys are one of the few that scientists have been able to keep under control. The bloodsucking fish still swim in the Great Lakes. But their numbers are down 90 percent. (Don’t worry, they don’t attack humans!)

Scientists keep treating about 200 rivers a year to get rid of baby sea lampreys. They’re also testing new ways to control the fish. One involves using a special smell to draw sea lampreys into traps.

This work has saved fishing in the Great Lakes. Today, this business brings in $7 billion a year. It gives work to 75,000 people. “Without sea lamprey control, the Great Lakes fishery wouldn’t exist as we know it,” says a worker at the U.S. Fish and Wildlife Service.

What about Beatrice, who’s 92 and has lived her whole life on the shores of Lake Huron? She’s grateful that her beloved Great Lakes were saved from the sea lamprey invasion. But most of all, she’s glad her days of beheading sea lampreys are over.

“Today, I wouldn’t touch one!” she says with a laugh.

In the 1890s, seeds of a plant called spotted knapweed were accidentally brought to the U.S. The weed has since spread across Montana and other states, where it takes over land that animals graze on. Experts use chemicals, mowers, and knapweed-eating bugs to get rid of it.

In the 1890s, seeds of a plant called spotted knapweed were accidentally brought to the U.S. The weed has since spread across Montana and other states. It takes over land where animals eat grass. Experts use chemicals, mowers, and knapweed-eating bugs to get rid of it.

The Asian citrus psyllid [SIH-lid] was first brought to the U.S. in the 1990s. It’s now found in several states. The insect spreads a disease that damages citrus trees and their fruits. In California, scientists have controlled the bug by closing off infested areas.

These weasel-like animals were brought to Hawaii in 1883 in the hope that they’d eat another invasive species—rats. The mongooses began devouring local birds instead. Traps and poison are used to control the animals.

These weasel-like animals were brought to Hawaii in 1883. People hoped that they’d eat another invasive species—rats. The mongooses began gobbling up local birds instead. Traps and poison are used to control the animals.

European settlers first brought pigs to America in the 1500s. The pigs have since run wild, particularly in Texas. They eat crops, kill farm animals, and spread diseases. Scientists are trying to reduce their numbers by trapping and hunting them.

European settlers first brought pigs to America in the 1500s. The pigs have since run wild, especially in Texas. They eat crops. They kill farm animals. They spread diseases. Scientists are trying to bring down their numbers by trapping and hunting them.

Burmese pythons were first brought to the U.S. as pets in the 1990s. Now, they’re gobbling up animals in Florida’s wetlands. Scientists are working to catch as many of the snakes as possible.

In the 1970s, the Asian carp was brought to the U.S. to eat pesky water plants. The carp are now starving out local fish in the Mississippi River. Scientists are using barriers to keep them from spreading.

In the 1970s, Asian carp were brought to the U.S. to eat pesky water plants. The carp are now starving out local fish in the Mississippi River. Scientists are using barriers to block them from spreading.

In 1890, European starlings were released in New York City on purpose. Today, 200 million of the birds destroy crops, threaten other birds, and pose a danger to airplanes across the U.S. Scientists have tried to control starlings in many ways, including with poison and fireworks.

In 1890, European starlings were let loose in New York City on purpose. Today, there are 200 million of these birds. They destroy crops. They threaten other birds. They pose a danger to airplanes. Scientists have tried using poison and fireworks to control the starlings.