Deep-sea distribution, biological and ecological aspects of Aristeus antennatus (Risso, 1816) in the western and central Mediterranean Sea

The object of the DESEAS Project, funded by the EC, was to gather preliminary data on the abundance and maximum depth distribution of the rose shrimp Aristeus antennatus in the Mediterranean Sea. An exploratory survey was therefore designed with that goal in mind and conducted on the R/V García del Cid, sampling the maximum depths in three specific areas in the central and western Mediterranean, one off Ibiza (Balearic Islands), one off Calabria (western Ionian Sea), and one off the southern Peloponnesian Peninsula (Gulf of Kalamata, eastern Ionian Sea). The depths sampled ranged from 600 to 4000 m, with specimens of A. antennatus being collected down to 3300 m. There were three distinct boundaries marking the abundance of this species: < 1000 m, relatively high abundance (up to 1000 ind km-2); 1000-1500 m, relatively moderate abundance (up to 300 ind km-2); and > 1500 m, relatively low abundance (<100 ind km-2). The known population structure of this shrimp species, with increasing proportions of males and juveniles with depth, was also recorded in the deep-sea regions in other areas of the Mediterranean. No evidence of any differences in gonad development or in the presence of spermatophores carried by females was found in any of the three sampling areas. Lastly, a tendency for the relative proportion of juveniles to increase with depth was also observed