Reducing Bycatch Mortality in Crab Pots in Virgina
The College of William and Mary, Virginia Institute of Marine Science employed commercial fishermen to test biodegradable panels and will use color avoidance mechanisms to reduce bycatch mortality of both actively fished and derelict crab pots.
Project Dates: March 2014 - March 2015
What is the project?
The Virginia Institute of Marine Science (VIMS) investigated the use of biodegradable escape panels and visual deterrents as mechanisms to reduce bycatch mortality of both actively fished and derelict peeler crab pots in the Chesapeake Bay.
Who is involved?
As part of the National Fish and Wildlife Foundation’s Fishing for Energy program and with funding from the NOAA Marine Debris Program, VIMS employed commercial watermen to compare catch rates of peeler pots outfitted with biodegradable escape panels to those with standard panels.
What does it accomplish?
Actively fished and derelict crab pots capture and kill outside of their targeted species; VIMS’ crab pot modification research, testing, and design aims to implement an effective mechanism to render the pots ineffective at capturing by-catch (a fish or other marine species that is caught unintentionally while catching certain target species and target sizes of fish, crabs, etc.) species, as well as prevent the continued "ghost fishing" of derelict pots, ultimately reducing the threat of by-catch and target species mortality.
By modifying 30 peeler pots with biodegradable escape panels and testing those alongside 30 standard peeler pots in a line (i.e. 1 standard, 1 modified, 2 standard, 2 modified, etc.) researchers tested whether the biopanels affect catch rates. Participants recorded the pot catch for each pot every time it was retrieved. And, at the end of the season, participants removed the biopanels for comparison to the starting weight and for determination of biodegradation rate estimates. Preliminary results suggest no adverse effect of biodegradable panels on peeler pot crab catch.
Additionally, VIMS and the College of William & Mary analyzed terrapin avoidance of crab pots based on entrance funnel color. Terrapins are visual predators and blue crabs are likewise strongly visual, and this research can help determine whether the color of by-catch reduction devices (BRDs) and/or the crab pot funnels can be modified to deter entry by terrapins and encourage entry by crabs. Currently, the movement of terrapins and crabs into pots is thought to be controlled by the physical dimensions of the funnel and BRD, but BRD color may influence turtle (and crab) behavior. VIMS conducted a series of lab and field experiments to determine whether the color of BRDs and crab pot funnels influences behavior of terrapins and crabs. Preliminary results suggest that color may play a role in deterring terrapin by-catch while enhancing blue crab catch.
What is something unique about the project?
While removal operations are not directly part of this project, the Commonwealth of Virginia employed seven watermen during the winter, trained in the use of side-scan sonar and experienced in removal, to locate and remove lost and abandoned crab pots with a concentration on peeler pots. The watermen removed 1,261 pots, 10 percent of which were peeler pots. The recovered pots contained 1,134 animals including blue crabs, black seabass, Atlantic croaker, flounder, terrapins, and ducks.