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Abstract

Hammamet Marina is the most important touristic port in the Gulf of Hammamet (Tunisia). The present work is a contribution to the knowledge of the functional diversity and structure of the malacofauna community in this area. Three different stations (A, B and C) within the port were sampled seasonally for a year (2005)(2006). The mollusc assemblage studied was represented by 14 species (in totally 2669 ind. were found). Among the four mollusc classes recorded, bivalves were the best represented (73.76% of the total number species), followed by gastropods (22.02%), cephalopods (2.42%) and polyplacophores (1.80%). Atlanto-Mediterranean (42.85%) and Endemic Mediterranean (39.28%) taxa prevailed in the community, followed by Indo-Pacific (7.14%) and cosmopolitan species (3.57%). A clear spatial zonation was distinguished. The station B hosted the highest abundance of gastropods (309±19.92 ind. m -2 ) and a species richness of 6±0.40. The station station A hosted the most equilibrated trophic structure, with a higher bivalve abundance (1378±99.23 ind. m -2) and a species richness of 6±0.1. Station C, located close to the mooring boats, presented the lowest abundance (230±17.47 individuals m -2 ) and the most affected assemblage. This station seemed to be affected by the higher anthropogenic pressure assessed compared to the other two stations, mainly oil pollution, due to the large quantities of hydrocarbon discharged from the boats.