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318 C. Brugnano et al. / Journal of Marine Systems 81 (2010) 312–322

Fig. 7. Hierarchical clustering on copepod species abundances: species assemblages.

Table 2 the lowest diversity. In fact, the horizontal copepod distribution
Mean abundances (ind. m− 3) of the most abundant species in coastal, neritic and pattern shows an abundance decreasing trend, and no relevant
changes in the copepod species composition across coastal, neritic and
pelagic stations (0–40 m layer). pelagic surface waters, even though, coastal area is characterized by
the occurrence of A. clausi, present in all the three above-said
Main copepod species Stations Neritic Coastal environments but with scarce abundances, and A. adriatica and
I. clavipes restricted only to coastal system in front of Sicily. In early
Acartia adriatica Pelagic 0.00 2.04 autumn, within this area the dominant coastal C. furcatus and
Acartia clausi 0.02 3.59 T. stylifera and the pelagic surface species A. negligens and O. plumifera,
Acartia copepodites 0.00 3.65 16.10 representing the surface assemblage in all the study area, play the
Acartia danae 0.68 0.02 0.00 most important role in contributing to similarity among samples.
Acartia negligens 3.85 2.92 7.49 Temperature and salinity ranges in surface layer allow these
Calanus copepodites 0.03 5.37 3.10 eurybiotic species to spread overall coastal, neritic and pelagic surface
Calocalanus copepodites 4.67 1.77 2.10 waters. These same or congener species constitute most of the
Calocalanus pavo 4.42 1.21 1.77 zooplankton assemblage in many temperate marine environments
Candacidae copepodites 1.75 0.68 1.92 (Raymont, 1983).
Centropages copepodites 1.36 1.41 5.91
Centropages typicus 1.50 1.09 4.24 According to Scotto di Carlo et al. (1985), there is a substantial
Centropages violaceus 2.79 0.33 0.24 continuity between coastal copepod and surface open water commu-
Clausocalanus arcuicornis 0.38 1.13 0.28 nity. This copepod community structure is characterized by species
Clausocalanus copepodites 0.39 15.47 22.28 with wide horizontal distribution that in correspondence to their
Clausocalanus furcatus 0.25 8.50 14.23 seasonal abundance peaks, from coastal spread over pelagic surface
Clausocalanus jobei 9.57 0.65 2.22 waters. In the same way, epipelagic species were found abundant in
Copilia copepodites 7.57 0.12 0.68 late summer–autumn, in coastal waters of the Mediterranean Sea,
Corycaeus brehmi 0.45 0.04 0.11 submitted to the influence of the open sea waters (Siokou-Frangou et
Corycaeus clausi 0.17 0.55 0.00 al., 1995). Dominant coastal copepod species were recorded for
Corycaeus copepodites 0.07 3.51 3.09 pelagic surface waters in many areas of the Mediterranean Sea (Vives
Corycaeus giesbrechti 0.17 1.19 2.01 et al., 1975; Pasteur et al., 1976; Scotto di Carlo et al., 1984; Siokou-
Corycaeus latus 3.31 1.31 1.11 Frangou et al., 1997).
Corycaeus typicus 0.72 0.61 0.67
Isias clavipes 1.28 0.00 1.13 The spatial and temporal distribution patterns of the main
Isias copepodites 0.78 0.00 6.34 copepod species in the Mediterranean have shown no substantial
Nannocalanus minor 0.00 2.73 1.71 differences, in early autumn. The key species found in coastal, neritic
Neocalanus gracilis 0.00 0.24 0.02 and epipelagic waters were C. furcatus, T. stylifera, and O. plumifera
Oithona plumifera 1.30 2.87 9.74
Oithona copepodites 0.12 13.86 54.44
Oithona atlantica 6.51 1.07 0.41
Temora copepodites 16.17 31.94 87.92
Temora stylifera 1.09 3.90 6.73
14.50
2.70