P.S.Z.N.: Marine Ecology, zyxwvutsr 19 (4): 293-309 (1998) zyxwv 0 1998 Blackwell Wissenschafts-Verlag, Berlin ISSN zyxwvutsrq 01 73-9565 Accepted: July 27, 1998 A Baseline Study on Benthic Species Distribution in Two Neighbouring Gulfs, With and Without Access to Bottom Trawling NOMIKI SIMBOURA”* ARGYRO ZENETOS’, MARIA-ANTONIETTA SOCRATES PAPASPYROU’ PANCUCCI-PAPADOPOULOU’, MARIA THESSALOU-LEGAKI’ zyx & ’ National Centre for Marine Research, Aghios Kosmas, 16604 Hellinikon, Greece. 2Zoological Laboratory, University of Athens, Panepistimiopolis, I5784 Athens, Greece. With 6 figures and 3 tables Key words: Benthic fauna, Aegean Sea, communities, baseline study, trawling. Abstract. An extensive survey of the benthic fauna was carried out at two neighbouring regions of the Aegean Sea, one normally trawled and the other closed to trawlers. Benthic samples were collected from seven areas located away from land-based sources. The faunistic analysis showed that species diversity and abundance was higher in the trawled area compared with the untrawled area, a fact which was attributed to the difference in sediment characteristics between the two areas. A degree of disturbance detected in the trawled area was evidenced by an increase in the number of polychaetes at the expense of other benthic groups and an abundance of some opportunistic species. This could possibly be related to trawling activities. as no other causes of disturbance were found in either area. Problem In the framework of the research project ‘Trawling Impact on Benthic Ecosystems’ financed by the European Commission, two neighbouring areas of South Evvoikos Gulf were chosen for an experimental trawling and environmental assessment study. The areas were chosen as most appropriate for this kind of study because they offer the advantage of comparing a sufficiently extensive undisturbed fishing area, neighbouring a normally trawled one. Evvoikos Gulf holds an important position in the Aegean Sea due to its special hydrographic conditions. Its southern part is divided into two main regions: the innermost part, South Evvoikos proper, is an elongated area which communicates with the North Evvoikos Gulf by the Euripus Channel and presents sedi- mentological properties of semi-enclosed areas. The southern part, called Petalioi * Author to whom correspondence should be addressed; e-mail: msim@lerato.fl.ncmr.gr U. S. Copyright Clearance Center Code Statement: 01 73-9565/98/1904-0293$14.00/0