Species distribution in the southern Aegean sea based on bottom-trawl surveys

Information on the distribution of the benthopelagic fauna of the southern Aegean sea was collected through two bottom-trawl surveys carried out at fixed sampling stations in the summers of 1996 and 1997. Discriminant analysis identified that the most important species in discriminating among station-groups in terms of numbers were: Pagellus erythrinus, Mullus barbatus, Mullus surmuletus, Diplodus annular-is, Spicara flexuosa, Sardina pilchardus and Parapenaeus longirostris. In terms of weight, the most important discriminating species were: Mullus barbatus, Pagellus erythrinus, Spicara maena, Scyliorhinus canicula, Loligo vulgaris and Parapenaeus longirostris. Supervised machine learning approaches and, in particular, the decision tree construction method were utilized in order to induce rules which determine the station-grouping. Several species, notably, Argentina sphyraena, Aristaeomorpha foliacea, Lepidorhombus bosci, Lepidotrigla cavillone, Mullus barbatus, Serranus cabrilla and Sepia officinalis appeared in most of the rules. (C) Ifremer/Cnrs/Inra/Ird/Cemagref/Elsevier, Paris.