As was reported in Scientific Reports, a new VIMS study focuses on a collaborative 6-year program to remove abandoned crab traps in the Chesapeake Bay, which showed that the effort generated more than USD 20 million in catch value for local fishermen. For Eastern Shore waterman, this may not be the be all to end all, but it does offer a way to supplement winter income, while relieving the bay of rogue pots.
The research, which was conducted by Professors Andrew Scheld, Donna Bilkovic and Kirk Havens, with support from NOAA’s Marine Debris Program, was funded through disaster-relief funds made available in 2008 after the US Department of Commerce declared the Bay’s blue crab industry a “commercial fishery failure” following several years of downward trending harvests.
The study modeled and compared crab harvests with and without the removal of derelict pots at several fishery-management areas in lower Chesapeake Bay. Calculated harvest numbers were then converted to monetary values “using the average annual dock price for hard-shell crabs in 2014 dollars”. Their harvest model used data on crabbing effort provided by the Virginia Marine Resources Commission, and stock abundance from the VIMS Winter Blue Crab Dredge Survey.
The removal of all this derelict gear, such as long-lines, gill and trammel nets, and trawling gear can also help other marine environments in other places; using the cleanup work in the Bay, this method provide economic benefits in elsewhere. The VIMS analysis showed that removing even just 10 percent of derelict pots and traps could “increase landings by 293,929 metric tons, at a value of $831 million annually”.
Andrew Scheld, an assistant professor at VIMS, says “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 percent increase above that which would have occurred had the pots stayed in place.”
“All told,” says fellow researcher Kirk Havens, “the crabbers removed 34,408 derelict crab pots during the program’s six-year run. At the same time, harvests and gear efficiency were observed to increase dramatically.” One of the reasons for the increased efficiency in crab harvests is that derelict gear can actually create a distraction from an active pot nearby.
“We estimate that crabbers harvested about 60 million more crabs due to the ghost-pot removalsThat’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,” Donna Bilkovic said.
Researchers also noted that removal efforts should focus on the most heavily fished sites, places where lost gear is most likely to accumulate.
“We found that removing only 10 percent of the pots taken during the actual program, if those efforts were focused on the 10 most-fished sites, would have increased blue crab harvests by 8,144 metric tons, or about 60 percent of the benefit we saw from the full removal program,” says Scheld.
The study also recommends a combination of preventative and mitigating measures should be part of a future road forward, “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.