Spatial and temporal patterns of anadromous alosine bycatch in the US Atlantic herring fishery

River herring, which comprise two species of anadromous alosines (alewife, Alosa pseudoharengus, and blueback herring, Alosa aestivalis), are under consideration for listing under the US Endangered Species Act. River herring populations have not rebounded despite reductions in directed fishing on these species and improvements in their freshwater and estuarine habitats. We examined recent (2005–2009) spatial and temporal patterns of fishing effort in the US fishery for Atlantic herring, Clupea harengus, and river herring bycatch patterns in this fishery. During the year, Atlantic herring fishing activity shifts spatially and temporally from the Northern Mid-Atlantic Bight and Southern New England waters in January–February, to Southern New England waters in March–April, to the Gulf of Maine in May–June, expanding to the Gulf of Maine and Georges Bank in July–August and September–October, respectively, and then contracting to the Gulf of Maine and Southern New England waters in November–December. At-sea fisheries observer data indicate that river herring bycatches in the Atlantic herring fishery occur mostly during January–April and September–December, primarily in Southern New England and the Northern Mid-Atlantic Bight waters. We discuss possible management measure to reduce these bycatches. Similar size, shape, and schooling behaviors between river herring and other pelagic species—and the high volume nature of the Atlantic herring fishery—limit the potential efficacy of gear-based bycatch mitigation measures. Hence, approaches such as regulatory management measures (e.g., time–area closures and catch caps) and improved fleet communication strategies (e.g., “move-on” rules) may be more practical and effective in minimizing river herring bycatch in the Atlantic herring fishery.

► Explained increasing attention to reducing oceanic bycatch of anadromous species.
► Examined seasonal patterns of river herring bycatch in the Atlantic herring fishing.
► Compared bycatch patterns to seasonal Atlantic herring fishing effort.
► Discussed possible management measures to reduce river herring bycatch.