Abundance and distribution of the deep-sea shrimp Aristeus antennatus larvae along the eastern Spanish Mediterranean coast (GSA 6)

The deep-sea blue and red shrimp Aristeus antennatus is a valuable fishing resource in the Northwestern Mediterranean Sea, currently under a local co-management plan in the port of Palam ' os (Spain). The management measures, although effective, might benefit other ports due to the dispersal patterns of the species pelagic larvae. Gathering information about A. antennatus larval distribution is a key step to describe these patterns, towards the establishment of well-dimensioned management measures. After a first detection of its larvae as the dominant species in the decapod community in Blanes submarine canyon, this broader approach tackles the entire management area along the Eastern Spanish Mediterranean coast (Geographic Subarea 6; GSA 6). Zooplankton sampling was carried out at 101 stations in surface waters (0.5-1 m) and in 8 stations in stratified vertical sampling (0-1200 m) during July-August 2016. Over 6500 A. antennatus larvae of all known stages were found, the first protozoea (PZ I) representing over 95% of the total. This is the first study taking into account the vertical migration of A. antennatus larvae, and we observed a broad distribution of PZ I throughout the water column. Plankton observations of the species larval distribution were supported by an Individual-Based Model suggesting aggregations in the northern submarine canyons, influenced by cold waters from the Northern Current and the geomorphology of the Ibiza Channel. The present study proposes a division of the GSA 6 in three zones to improve fishery management measures.