Posidonia oceanica L. (Delile) Meadow from Messioua banc (Tunisia)

Abstract

In order to study the benthic ecology of the “Messioua banc” (30 NM east off Zarzis, Southern Tunisia), a traditional Tunisian sponge fishing ground, four marine campaigns were conducted with the R/V “Hannibal” from October 2000 to August 2001. The objectives of three of these campaigns were field validation, focusing on the sampling of the Posidonia oceanica meadow and of the sponge population. However the goal of the fourth one, with the use of a multi-beam sonar SEABAT 9001 (Reson Co.), was the mapping of bottom of the surveyed area and the scanning of the Posidonia meadow and its sponge population. The field work allowed the study of sixteen stations covered by a dense meadow extending from 21 to 33 m depth, which present the highest density of shots/m² and the biggest Leaf Area Index in the Mediterranean region.