Distribution and abundance of Octopus vulgaris Cuvier, 1797 (Cephalopoda: Octopoda) in the Mediterranean Sea

Abstract

Information on distribution, abundance and size composition of the common octopus Octopus vulgaris was obtained from the MEDITS trawl surveys, carried out in a wide area of the Mediterranean basin from 1994 to 1999. The species showed a wide geographic distribution, since it was collected in all the major areas investigated, but differences were highlighted among the 40 geographic sectors sampled. O. vulgaris showed a narrow depth distribution, mostly restricted to within 100 m. Catches below 200 m were scarce and occasional at deeper sea bottoms. Further analysis between major areas in the depth strata 10-50 m and 50-100 m showed the Alborán Sea and Sardinian waters as the areas where the abundance of the species was the greatest. Size frequency distributions showed a wide size range, even if large individuals were represented in a very low proportion. The surveys highlighted the relevant presence of small individuals in almost all the analysed areas. Recruits with a modal length of 5-6 cm mantle length constituted the dominant mode in the histograms of a great extent of the Italian coasts and in Morocco and Corsica waters.