A SPATIAL-ANALYSIS OF THE COMMERCIAL FISHERIES CATCHES FROM THE GREEKAEGEAN SEA

In the present study, univariate (number of species, species diversity , eveness, richness) and multivariate analysis techniques (cluster ana lysis and multidimensional scaling) are used, together with dominance curves, to describe the major biogeographical features of the demersal and pelagic fisheries in ten Greek statistical fishing subareas of th e Aegean Sea for the years 1982-1987, inclusive. The results from the various statistical techniques applied were in close agreement and all suggested that the ten statistical fishing subareas could be generall y grouped into three main areas (northern, central and southern Aegean Sea) for the pelagic fishery and into two main areas (northern and so uthern Aegean Sea) for the demersal fishery, which differed considerab ly from each other in terms of species composition, species diversity and catch density (catch weight per unit area). In general, with respe ct to the pelagic fisheries, the catches from the northern, central an d southern Aegean area groupings are dominated, respectively, by ancho vy (Engraulis encrasicolus (L.), 48.2%), horse mackerels (Trachurus sp p., 23.2%) and bogue (Boops boops (L.), 40.6%). For the demersal fishe ries, the catches from the northern and southern Aegean area groupings are dominated by grey mullets (Mugilidae, 10.3%) and pickerel (Spicar a smaris (L.), 28.6%), respectively. The main factors which appear to be contributing to this geographical group differentiation are: (a) th e gradient in the relative eutrophy, river runoff, temperature and sal inity of the Aegean Sea waters along a NNW to SSE axis; and (b) the di fferences in extent of the continental shelf within these areas of the Aegean Sea. The managerial implications of the results of these spati al analyses are discussed and emphasis is given to the experimental es tablishment of marine harvest refugia which provide a refuge for fish populations in space, rather than the 'refuge in numbers' which has be en the basis of most traditional fisheries management measures so far applied in this area.