Seasonal and bathymetrical population displacements of the deep-sea red shrimp (Aristeus antennatus) in Blanes and Palamós submarine canyons (Northwestern Mediterranean) using Vessel Monitoring System and Geographic Information Systems

Abstract

The deep-sea red shrimp Aristeus antennatus is the target of the most important fisheries along the Spanish Mediterranean coast. In the north Catalan margin, submarine canyons are the main geomorphological feature where populations of deep-sea red shrimp present marked seasonal and bathymetric displacements related to its reproductive biology. We here present the changing dynamics of a fleet that follows the reproductive displacements of this species, analyzed by combining a two-year biological survey together with daily landings and georeferenced VMS (Vessel Monitoring System) data. The spatial and bathymetric displacements of the red shrimp fishery in two of the most relevant ports in the Northwestern Mediterranean, Blanes and Palamós (Catalonia, Spain), are shown in a series of maps covering the period from 2005 to present date. Survey data and daily landings per commercial size class of individuals, supplied by the fishermen’s associations of both ports, were merged with VMS data from the Spanish Ministry of Agriculture, Livestock and Fisheries to graphically represent the effort, landings per size class and CPUEs in different fishing grounds within the submarine canyons and adjacent open slope. By comparing the evolution of the CPUEs and daily landings associated to each of the locations, we were able to show the differences in the fishing effort held on each size class of the population, as well as the shrimp movements over time. The resulting series of maps shows that the most exploited area corresponds the fishing grounds located on the head of the two submarine canyons, where juveniles move between the months of January and February