Seasonal Trends in Groundfish Discards on Georges Bank: Implications for Adaptive Quota Management

Abstract

AbstractFor fisheries to be sustainable, management should account for all major sources of fishing mortality. On the Canadian side of Georges Bank, landings and discards of transboundary stocks of Atlantic Cod Gadus morhua, Haddock Melanogrammus aeglefinus, and Yellowtail Flounder Limanda ferruginea are monitored against quotas that are shared by the Canadian groundfish and scallop (sea scallop Placopecten magellanicus) fisheries to limit fishing mortality. The shared quota allocations are managed using an adaptive quota management system; quota can be redistributed between the fisheries during the season to maximize fishing opportunities, while still respecting the overall catch limits. However, the redistribution relies on estimates of the total end‐of‐year discards of Atlantic Cod, Haddock, and Yellowtail Flounder from the scallop fishery. Here, we evaluated and compared two approaches for projecting end‐of‐year discards within season: an empirical method based on scallop fishery landings and a seasonal modeling approach. Seasonal trends in discards were identified, with discards of all three groundfish species highest in April or May. The seasonal models out‐performed the empirical landings‐based projection method, and our results demonstrate that accounting for seasonal patterns in discards better informs risk‐based fishery management decisions.