In 2008, Virginia began paying fishermen to pull ‘ghost traps’ from Chesapeake Bay; six years of cleanup helped unlock an estimated $21 million in extra crab catches

For many years the crab pots which had been abandoned were lying under the waters of the Chesapeake Bay and were still able to attract crabs even though the fishers who had owned them were long since disappeared. To someone who was only looking at the scene they might have appeared to be no more than forgotten rubbish.

What if the traps that had gone missing were simply being used to draw money out of the pockets of working watermen?

In 2008 Virginia started paying fishermen to retrieve the crab pots that had been lost in the Chesapeake Bay, and as a result there was a six-year campaign to clean things up which achieved more than simply getting the abandoned fishing gear out of the water. When the programme had come to an end in 2014, the researchers estimated that the removal of thousands of abandoned crab pots had resulted in an extra $21.3 million being added to the value of the blue crab harvest, as per Virginia Institute of Marine Science.


How could it be that removing old traps from the Bay would result in such a big economic return?The answer lies in what those abandoned pots continued to do long after they were lost.

For years, crabbers had been losing pots because of storms, boat propellers and other causes. Left behind, the gear could continue attracting and trapping crabs. Researchers at the Virginia Institute of Marine Science wanted to understand not only the environmental damage caused by this “ghost fishing,” but also what it meant for the people whose livelihoods depended on the blue crab fishery.

The results showed that removing the lost gear could have a striking effect on harvests.

What happened when the ghost pots were removed?

The removal program operated in lower Chesapeake Bay between 2008 and 2014. Rather than relying only on specialized cleanup crews, the effort employed commercial crabbers to locate and remove derelict crab pots during their winter closed-fishing seasons.

Over the six years, watermen removed 34,408 derelict crab pots.

“At the same time, harvests and gear efficiency were observed to increase dramatically,” says Kirk Havens, a professor at VIMS and co-author of the study.

The researchers estimated that the cleanup resulted in an additional 13,504 metric tons of crab harvest, worth $21.3 million. That represented a 27% increase over what they estimated would have been harvested if the derelict pots had remained in place.

The study’s lead author, Andrew Scheld, an assistant professor at VIMS, said the economic consequences of ghost fishing have rarely been quantified.

“it’s well known that derelict fishing gear can harm the environment and increase crab mortality, but the economic impacts of this ‘ghost fishing’ have rarely been quantified. Our study shows that VIMS’ collaborative efforts to remove ghost crab pots from the lower Bay led to an additional 13,504 metric tons in harvest valued at $21.3 million—a 27% increase above that which would have occurred had the pots stayed in place.”

Why did removing old traps matter?

The researchers attributed the increase in harvest partly to reduced competition from derelict pots. A lost pot does not necessarily become irrelevant simply because a fisherman can no longer retrieve it. According to Scheld, derelict gear can interfere with active fishing by attracting crabs or discouraging them from entering nearby working pots.

“Derelict gear can distract or deter a crab from an active pot nearby, lowering the catch of watermen and damaging the commercial fishery.”

Donna Bilkovic, another VIMS professor and study co-author, estimated that the cleanup helped crabbers harvest about 60 million additional crabs.

“We estimate that crabbers harvested about 60 million more crabs due to the ghost-pot removals,” says Bilkovic. “That’s one extra blue crab each time a pot is retrieved—crabs that would have otherwise been captured or attracted to the now absent derelict gear.”

That estimate helps explain why the economic effect was much larger than the simple value of the cleanup itself. Removing a single piece of lost gear could improve catches from active fishing operations nearby.

How did researchers calculate the economic benefit?

The scientists modeled blue crab harvests across 54 fishery-management areas in lower Chesapeake Bay. They compared expected harvests with the derelict pots removed against what would have happened if the gear had remained. The model combined information about crabbing effort from the Virginia Marine Resources Commission with stock-abundance data from the VIMS Winter Blue Crab Dredge Survey.

The researchers then converted the estimated harvest into monetary value using the average annual dock price for hard-shell crabs, expressed in 2014 dollars.

Their analysis showed that the cleanup program had a substantial return on investment. The six-year effort cost $4.2 million, while the additional blue crab revenue was estimated at $21.3 million.

“The benefits far outweighed the program’s total cost,” says Scheld.

The program itself was funded through disaster-relief money made available in 2008, after the U.S. Department of Commerce declared the Bay’s blue crab industry a “commercial fishery failure” following years of declining harvests.

The research, published in Scientific Reports, was supported by NOAA’s Marine Debris Program.

Could a smaller cleanup have produced a big return?

The researchers also examined whether the cleanup could become more efficient by concentrating efforts in areas where lost fishing gear was most likely to accumulate.

Their findings suggested that location mattered.

Removing only 10% of the pots taken out during the actual program, but focusing those removals on the 10 most heavily fished sites, was estimated to produce 8,144 metric tons of additional blue crab harvest.

That was about 60% of the benefit generated by the full removal program, according to Scheld.

The finding points to a practical challenge facing derelict fishing gear programs. Removal funds are limited, and fishing gear will continue to be lost. That makes it important to consider where cleanup work can produce the greatest effect.

Could removing ghost gear work beyond Chesapeake Bay?

The researchers extended their analysis beyond the Chesapeake Bay blue crab fishery to examine the potential economic effect of removing derelict pots and lobster traps from major crustacean fisheries around the world.

Their analysis estimated that removing just 10% of derelict pots and traps could increase landings by 293,929 metric tons, with an estimated annual value of $831 million.

The researchers also pointed to other forms of lost fishing equipment, including trammel-nets, gillnets, long-lines and bottom-trawling gear.



Havens noted that such gear can continue attracting target and non-target fish in marine environments, much as ghost pots attract crabs. Scheld said removing those types of gear could therefore generate economic benefits similar to those observed in the Chesapeake Bay blue crab fishery.

The researchers ultimately recommended combining cleanup with prevention.

Crab pots equipped with biodegradable escape mechanisms could help reduce the effects of gear that is lost, while concentrating removal efforts in areas with the greatest fishing pressure could make cleanup spending more effective.

“Ensuring both that crab pots have biodegradable escape mechanisms and that removal efforts target areas of highest fishing pressure are likely to yield benefits superior to any single strategy alone,” says Scheld.

The scientists also cautioned that the financial return from derelict gear removal will depend on the cost of carrying out the work, which can vary considerably between fisheries.

Still, the six-year Virginia program offered a clear economic finding within the Chesapeake Bay: removing abandoned fishing gear was not simply a cleanup expense. According to the study’s estimates, it helped put millions of dollars of additional crab harvest within reach of the watermen who depended on the fishery.

FAQs

1. How many ghost pots were removed?
   Watermen removed 34,408 derelict crab pots between 2008 and 2014.
2. How much extra crab revenue was estimated?
   Researchers estimated an additional $21.3 million in blue crab harvest value.