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and ostracods (5.18 %). Copepod assemblage was represented by 110 specie, but it was
mainly constituted (76.73 %) by juveniles, belonging to the genera Temora, Oithona,
Clausocalanus, Calanus, Pleuromamma, Centropages, Acartia, Corycaeus, and
Ctenocalanus, and adult of the species Clausocalanus furcatus, Oithona atlantica,
Temora stylifera e Acartia negligens. Abundance patterns and species composition were
mainly affected by depth and offshore or inshore position of each station.

1. INTRODUCTION

The Mediterranean Sea is a marginal basin formed by two principal sub-basins
(the Western and the Eastern Mediterranean) that are connected by Sicily Channel. The
Egadi Archipelago which is constituted by the islands of Favignana, Levanzo and
Marettimo, is located offshore the westernmost Sicily coast in the southern part of
Tyrrhenian Sea, at the entrance of Sicily Channel. This area plays an important role in
hydrodynamic and biological exchanges between Western and Eastern Mediterranean
basins. The peculiar morphological, hydrological and hydrodynamic features of Sicily
Channel significantly influence distribution and composition of plankton and, in
particular, copepod communities. In the last decade, studies carried out in the Eastern
Mediterranean (Siokou-Frangou et al., 1997) compared meso-zooplankton (Mazzocchi
et al., 1997) and copepod community structures in the offshore waters of Sicily
Channel, to ones in the Ionian Sea, Cretan Passage, Rhode area and Levantine Sea.
Meso-zooplankton and copepod assemblages from the Egadi Islands are very poorly
known. A study was carried out in the area to identify a nursery area for the species
Thunnus thynnus in Egadi Island Archipelago (Carli et al., 1973). The surface
zooplankton was investigated in that survey by using a net with a 500 μm mesh size
which caused the lost of the smallest organisms.

The present study provides more detailed information about spatial distribution of
copepod species, their abundance and distribution in relation to physical chemical and
biological parameter in the hydrographical area of Egadi Islands, using, for the first time
in this area, electronic multiple net BIONESS which allows to simultaneously recording
abiotic and biotic parameters while zooplankton samples are being collected.

2. STUDY AREA

The Egadi Archipelago is constituted by Marettimo, Levanzo and Favignana
Islands. This area represents the shallowest part of a wide submarine canyon by which
Sicilian continental shelf is connected to the Tyrrhenian Sea abyssal plane (Colantoni et
al., 1993). The Sicilian continental shelf is very broad in front of Trapani coastlines and
is narrower between Levanzo and Marettimo. In the northern part of this sector,
continental slope abruptly reaches and exceeds 1000 m depth. In this area, surface
circulation is mainly characterized by the flow of Atlantic water from the Sardinia
Channel into the Tyrrhenian Sea (Astraldi et al., 1996) and the Levantine Intermediate
water, produced in the Eastern Mediterranean Sea and settled at a depth of 100-200 m,

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