Raised-Footrope Gill-Net Modification Significantly Reduces Subadult Atlantic Sturgeon Bycatch

Abstract

Bycatch is a major problem in most commercial fisheries around the world and is among the greatest challenges for fisheries managers tasked with conserving, protecting, and sustaining marine resources. Bycatch of protected species is particularly problematic because even small levels of bycatch mortality can hinder conservation efforts. The federally protected Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus is one such example. Unknown numbers of Atlantic Sturgeon are caught as bycatch in commercial gill-net fisheries along the U.S. Atlantic coast, with discard mortality rates as high as 51%. The Striped Bass Morone saxatilis sink gill-net fishery in the James River, a tributary to Chesapeake Bay, is the only inshore fishery in Virginia with mesh sizes (13.3–20.3-cm stretched mesh) that are large enough to have high levels of Atlantic Sturgeon bycatch. This study was conducted during the spring fishery and examined a modified gill-net design that incorporated a raised footrope at the bottom of the net, creating an approximately 1-m space between the benthos and the net. The modified net was fished alongside conventional commercial gear to evaluate catch rates of Striped Bass and Atlantic Sturgeon in each gear. Our findings showed that the experimental net significantly reduced bycatch of Atlantic Sturgeon (64.3%) and significantly increased the landings of Striped Bass (45.6%). This gear should be considered as a management option for the spring Striped Bass fishery in Virginia and any fishery in which subadult Atlantic Sturgeon are the primary bycatch. Additional research on seasonal orientation of Atlantic Sturgeon in the water column is needed before adopting the raised-footrope design in the presence of adults on spawning runs.