although strong winds may cause destratification during summer. Mean surface temperatures in the summer months are well above 208C, with maximum values above 268C in July and August, while minima in February–March are below 108C. The southeastern part of the Gulf shows variability in surface salinities ranging from slightly above 32 (in late spring and late autumn) to values close to 38 in winter and late summer. The Gulf is classified as a moderate eutrophic area (Flander-Putrle and Malej, 2003) with primary production ranging from 0.2 to 15.9 mmol C dm23 day21 (Malej et al., 1995; Cantoni et al., 2003) and mean mesozooplankton dry weight and ash-free biomass 18.5 and 13.6 mg m23, respectively (Benovic´et al., 1984; Fonda Umani et al., 1992).