Demersal fish assemblage biodiversity as an index of fishery resources exploitation

Until 1996, scientific information about groundfish assemblages on southern Adriatic trawlable bottoms almost exclusively referred to the western side of the same basin (Italian waters). During 1996, for the first time, a sum mer trawl survey was carried out along the full South Adriatic area. A tota l of 93 demersal fish species was obtained and the 'species abundance (biom ass)/sampling stations' matrix was analysed by means of cluster analysis. T he analysis was useful to discriminate the shelf and slope assemblages on b oth sides of the South Adriatic and to compare biodiversity This was determ ined with univariate ecological indices (diversity, equitability) and graph ical methods (ordinary, cumulative, and partial dominance; abundance/biomas s comparison curves). Fish assemblage biodiversity was higher on shelf bott oms of the eastern Adriatic side (Albanian waters) than the western shore ( Italian waters). The highest catch yields, referring to the main "target" t rawl fishery species, were usually found along the Albanian shore.