Black scabbardfish (Aphanopus carbo) longline fishery off the Portuguese continental coast: Spatial information in support of deep-sea fisheries regulations

Abstract

The main objective of this study is to provide, for the first time, fisheries-dependent, spatially explicit information on the activity for the black scabbard fish (Aphanopus carbo) longline fleet operating off the Portuguese coast. Fisheries monitoring data were analysed, covering the period 2014–2016, aiming at identifying deep-sea fishing grounds, gaining a better understanding of the fleet spatial dynamics, quantifying fishing effort and providing information on the species distribution and abundance. E-logbooks were used to define general patterns of fishing activity, while the combined analysis of Vessel Monitoring System (VMS) and Automatic Identification System (AIS) data allowed to spatially identify fishing trips and define haul-back trajectories corresponding to fishing events. A total of 19 vessels were found to be involved in this fishery, mainly operating at depths from 1000 to 1500 m, landing the black scabbard fish in two main ports located in the centre and three secondary ports in the northern region. Fishing effort and catch per unit of effort (CPUE) were estimated and mapped for the period in study and the geographic extension of the fishery in the Portuguese continental slope was highlighted. Vessels keep their activity spatially restricted, in a clear strategy to avoid competition; their areas of activity are contiguous and generally related to the closest port. Some recommendations are drawn in support of a continuous monitoring programme for this fishery.