Fisheries Resources in the Deep Waters of the Eastern Mediterranean (Greek Ionian Sea)

Abstract

The deep waters of the Greek seas are unexploited, since trawling is carried out mainly down to 400 m. In the present work, the fisheries resources of the deep waters (300900 m) of the Greek Ionian Sea were studied in spring, summer and autumn 2000 by means of experimental trawl surveys. The results showed that in the zone 300500 m, fish composed 7383% by number or 8992% by weight of the catch depending on the season, crustaceans 1625% by number or 6% by weight and cephalopods 12% by number or 35% by weight. In the zone 500700 m, crustaceans composed 2841% by numbers or 6780% by weight of the catch, whereas the proportion of cephalopods was less than 1% by number and about 1% by weight. In the deepest zone (700 900 m), the proportion of cephalopods remained negligible, whereas the proportion of fish increased and was about equal in numbers with that of crustaceans, whereas in weight it ranged from 81 to 86%. The CPUE of commercial fish was 2359 kg/hr in the first depth stratum, 725 kg/hr in the second one and 210 kg/hr in the third one, depending on the season. Concerning the commercial crustaceans, their CPUE was 36.5 kg/hr in the shallowest zone, 68.5 kg/hr in the middle one and 24 kg/hr in the deepest one. The commercial part of cephalopod catch ranged from 1 to 7 kg/hr in the zone 300-500 m, whereas deeper it was negligible. Commercial/total ratio by weight of the whole catch was highest in the 500700 m zone (0.600.78), whereas in the other zones it was generally lower than 0.50.