DEEP-SEA DECAPOD FAUNA OF THE WESTERN MEDITERRANEAN - BATHYMETRIC DISTRIBUTION AND BIOGEOGRAPHIC ASPECTS

A total of 57 bottom trawl hauls, using an OTSB-14, were carried out at depths between 862 and 2265 m in the Catalan Sea in 1988 and 1989. 28 species were identified including 6 Dendrobranchiata, 1 Stenopodidean, 7 Caridea, 2 Thalassinidea, 2 Palinura, 3 Anomura, and 7 Brachyura. Munidopsis tridentata, Chaceon mediterraneus and a new species of Axiidae were the most important faunistic records in this survey. Changes in the decapod crustacean fauna in the Catalan Sea were reflected by an impoverishment of species with increasing depth. The most pronounced qualitative changes in the fauna were recorded between 1000 and 1200 m and at around 2000 m. The bathyal decapod fauna in the western Mediterranean is quite similar to that in the Atlantic. The most important families and genera common to both bathyal zones are the Crangonidae, Galatheidae and Geryonidae, and the genera Nematocarcinus and Stereomastis. In contrast, the tropical species Aristeus antennatus, Acanthephyra eximia, and Plesionika acanthonotus, that are of little importance in the North Atlantic, are widely distributed and frequent in the deep western Mediterranean.