Demersal fish assemblages from the bathyal grounds of the Ionian Sea (middle‐eastern Mediterranean)

Abstract

Data collected during four trawl surveys conducted in the Ionian Sea were used to describe the structure and spatial distribution of the demersal assemblages (fishes, crustaceans and cephalopods) on the bathyal grounds. Samples were taken from depths of 200 to 700 m during spring and autumn of 1994 and 1995. Classification and ordination of the demersal communities were conducted with cluster and correspondence analyses, respectively.

Speciesasswere associated with depth. Two faunal assemblages were identified in the uppermost (about 200–400 m) and in the deepest (about 400–700 m) investigated bottoms. The former was characterized by greater abundance and biomass of mostly hake, blue whiting, rose shrimp and Norway lobster. The latter was represented by deep‐water sharks, macrourids and deep‐water decapod crustaceans. On the upper slope, two main geographic areas (one north of the Taranto valley the other south) were distinguished in the correspondence analysis.

Key words:

• Fish assemblages
• Cluster analysis
• Correspondence analysis
• Ionian Sea