Scientists Disagree on Lost Gear, Crab Data in Chesapeake Bay

May 29, 2018

A derelict crab pot washed up on one of Virginia's miles of shoreline on Chesapeake Bay. Many lost traps lie on the bottom of the bay and its tributaries, according to VIMS.
Credit Pamela D'Angelo

Last year, a scientific report put some astounding numbers to crab pots lost by watermen and the subsequent economic loss when they become death traps for crabs that wander in and can't escape.

Now, a committee of federal and state crab scientists say those numbers were overestimated.

Behind your pile of steaming Chesapeake Bay blue crabs are teams of scientists working hard to make sure there's enough out there to harvest. Back in 2016, a group of scientists from William & Mary's Virginia Institute of Marine Science said the Chesapeake Bay regional industry was losing millions of dollars worth of crabs to derelict crab pots, also called ghost pots.

Glenn Davis chairs the Chesapeake Bay Stock Assessment Committee, part of the Chesapeake Bay Program partnership, that includes federal and state agencies, local governments, non-profit organizations and academic institutions. He told a meeting of fisheries managers, last winter, those numbers are wrong.

"From the spatial model that was used, to the data inputs, to the assumptions that were made is that at every step of the way it created an overestimate in both the number of pots and the number of crabs that were caught within those pots," Davis admits.

Kirk Havens, Director of the Coastal Watersheds Program for VIMS, is one of the scientists who conducted the study and co-authored the derelict crab pot report.  "There has been some discussion amongst the managers on how big an impact the annual loss of 3 million crabs due to the derelict pots could have on the overall population of crabs in the bay," Havens said. “It's probably relatively small compared to the overall population of crabs which is in the hundreds of millions, but it is a known loss of market-sized crabs that can be managed."

But once the data is out, it's hard to take it back. In this case, the VIMS data has been used to market a solution to derelict crab pots-- biodegradable panels that would dissolve and leave an escape hole. Havens and his team are the inventors. A Richmond-based entrepreneur bought the license from William & Mary and began producing the panels, using the VIMS data to market them. State Senator Monty Mason sponsored a bill to mandate biodegradable panels earlier this year and also used the data to gain support.

Waterman Daniel Knott holds one of the crab pots he used in the testing of biodegradable panels that failed.
Credit Pamela D'Angelo

That caught the attention of Daniel Knott, the waterman we interviewed for our previous story who was trying out the panels.  "You can see how brittle they become," Knott said as he snapped pieces of the panel. "They all failed, failed at different levels and at a pretty good cost of time and energy to fix the pots once these panels started failing."

Cost was also a factor. These particular biodegrable panels cost upwards of $1.50 per pot compared to the ten cent plastic cull rings they were using. Mason's bill required two per pot. Knott wrote several senators with his concerns. The bill was defeated. But Senator Mason says he'll keep working on the problem, even if the VIMS data is off.  "When is the problem going to be significant enough for us to address it," Mason wondered? "It's still a problem. It's not as big as we thought, but over year, after year, after year it adds up, so we need to focus on addressing it and that will come. "It's just a matter of when.”

Earlier generations of biodegradable panels Knott said failed out on the water.
Credit Pamela D'Angelo

Havens said Knott was given older panels that proved to have a shorter shelf life. Wade Blackwood, the entrepreneur producing the panels has a fifth generation that he says lasts longer. He's already asking watermen to test them. "I know the data is under dispute but the data is pretty damning. Whether you lose one trap or 100 it's still a lost trap. It fishes for a certain period of time...whether it's a year or five years, it's still a problem," Blackewood said.

Senator Mason says a new bill won't mandate biodegradable panels. Instead, he'll look at incentives, such as bringing back a program that hired watermen to collect derelict pots during the off-season. And he'd consider including other types of less expensive biodegradable panels, like those used by other states such as Florida, where seven different kinds are allowed.

This report, provided by Virginia Public Radio, was made possible with support from the Virginia Education Association.