Abundance and distribution of the deep-sea blue and red Aristeus antennatus larvae in the North-western Mediterranean

Abstract

The deep-sea blue and red shrimp Aristeus antennatus (Risso, 1816) is one of the most valuable fishing resources in the Northwestern Mediterranean, currently under a local co-management plan in the port of Palamós (Spain). Gathering information about its larval distribution is a key step for the progress of its fishing stock assessment and the establishment of well-dimensioned management measures. We here present the spatial distribution of A. antennatus larvae at the peak of the species´ spawning period (July-August) along the Spanish Mediterranean coast. Zooplankton sampling was carried out in surface waters (0.5 to 1 m depth) in the summer 2016 with a 1 m-mouth neustonic sledge (mesh size: 300 µm) over bottoms of 82 to 1840 m. Samples were rinsed in distilled water, preserved in 96% ethanol and sorted in the laboratory under a stereomicroscope. Identification of the larvae was done according to the available descriptions. Over 1000 A. antennatus larvae of all known stages were found in our samples, the first protozoea representing almost 90% of the total. Results show aggregations of larvae in the Ibiza Channel and in the northern submarine canyons, concurrent with hydrographic conditions. No larvae were found below the Ibiza Channel. These data will be useful to assess the species´ larval dispersal and validate a biohydrodynamic model of the study area