Crab Trap Cleanup

Back in 2009, scientists and students from Stockton University in New Jersey set out by boat for the Mullica River. They were searching for shipwrecks at the bottom of the river, which flows into New Jersey’s Great Bay.

To scan the riverbed, the team used an instrument called sonar. Sonar sends out vibrations and measures how long they take to bounce off surfaces. The measurements let the team see the shape of nearby objects and their distance away.

Suddenly, a light flashed on the sonar screen. It wasn’t a ship—it was a collection of metal traps. People who fish for crabs, called crabbers, lay these along the seafloor. The traps catch crabs that the crabbers sell for people to eat. But sometimes, the traps don’t make it back to the surface.

Scientists and students set out by boat back in 2009. They were headed for the Mullica River. The group was from Stockton University in New Jersey. They were searching for shipwrecks on the bottom of the river. It flows into New Jersey’s Great Bay.

The team scanned the riverbed. They used a device called sonar. Sonar sends out sound waves that bounce off surfaces. The sonar measures how long it takes the sound waves to return. That lets the team see the shape and location of objects.

Suddenly, a light flashed on the sonar screen. It wasn’t a ship. It was a bunch of metal traps. People called crabbers fish for crabs. They lay traps along the seafloor to catch the animals. Crabbers sell the crabs for people to eat. But sometimes the traps don’t make it back to the surface.

These lost traps—along with nets and ropes—are examples of “ghost gear.” The lost fishing devices litter oceans worldwide, harming animals and damaging boats. “Anywhere fishing is going on, there is gear that can go missing,” says Mark Sullivan, a marine scientist at Stockton. 

Since that first discovery in 2009, the Stockton group has made it their mission to clean up the seafloor off New Jersey’s coast. In other areas, organizations are training people to remove lost gear. These efforts could help banish many of these “ghosts” from the oceans. 

These lost traps, plus nets and ropes, litter oceans all over the world. They’re known as “ghost gear.” This lost fishing gear can harm animals. It can also damage boats. “Anywhere fishing is going on, there is gear that can go missing,” says Mark Sullivan. He’s a marine scientist at Stockton.  

Now the Stockton group has a mission. They want to clean up lost traps from the seafloor off New Jersey’s coast. Groups are training people to do the same in other areas. That could help remove many of these “ghosts” from the oceans.  

After the Stockton scientists found the traps in the Mullica River in 2009, they wanted to know the scale of the ghost gear problem in the estuary. That’s the area where a river’s fresh water mixes with salt water from the sea. In 2011, they counted 2,218 traps in the 18-square-kilometer (7-square-mile) area!

In 2013, with funding from the National Oceanic and Atmospheric Administration, scientists set out to remove the traps. They made maps of the seafloor with sonar scans and gave them to five local crabbers. The crabbers used the maps to find ghost traps, then snagged each trap with a metal chain.

From 2013 to 2017, the team was able to remove 80 percent of the 2,218 traps. Scientists let crabbers keep the traps that were in good shape and recycled the rest. Traps were not the only objects they found! “We also pulled up chairs, a half of a motorcycle, and an 800-lb tree stump,” says Warren Unkert. 

First, the Stockton scientists wanted to know the size of the ghost gear problem. They studied the Mullica River and nearby estuary. That’s where a river’s fresh water mixes with the sea’s salt water. The estuary covers an 18-square-kilometer (7-square-mile) area.

The scientists counted 2,218 traps there in 2011! The scientists got funding in 2013. It came from the National Oceanic and Atmospheric Administration. They got to work removing traps. They made sonar scans of the seafloor. They then made maps. They gave the maps to five local crabbers. The crabbers used them to find ghost traps. Then they snagged each trap with a metal chain.

The team removed 80 percent of the traps over four years. The crabbers kept traps that were in good shape. They recycled the rest. And traps weren’t the only objects they found. “We also pulled up chairs, a half of a motorcycle, and an 800-pound tree stump,” says Warren Unkert.

Organizations in other areas are cleaning up ghost gear too. In Florida, Ocean Aid 360 hosts a series of events called The Ghost Trap Rodeo, where people compete to recover traps. The group GhostNets Australia has trained and paid Australian locals to clear nets and turn them into artwork.

In the New Jersey estuary, the goal is to keep traps from piling up in the estuary again. The Stockton team now helps other groups run cleanups along New Jersey’s coast. They lend crabbers low-cost sonar to find their own missing traps.

Last year, the Unkerts found most of their lost traps. They’re glad to be helping keep the water safer for people and wildlife. “We’re doing this to benefit the whole community,” says Karen Unkert.

Groups in other areas are cleaning up ghost gear too. Ocean Aid 360 is in Florida. It hosts a series of events called the Ghost Trap Rodeo. People compete to find traps. The group GhostNets is in Australia. It trains and pays locals to clear nets and turn them into artwork.

The goal in the New Jersey estuary is to keep traps from piling up again. The Stockton team now helps other groups run cleanups along the coast. They lend crabbers low-cost sonar to find their own missing traps.

The Unkerts found most of their lost traps last year. They’re glad to be helping keep the water safer for people and wildlife. “We’re doing this to benefit the whole community,” says Karen Unkert.