Diversity and geographical distribution of soft-bottom macrobenthos in the bay of Bou Ismail (Algeria, Mediterranean Sea)

Abstract The macrobenthic fauna in the bay of Bou-Ismail (Mediterranean Sea, Algeria) was studied with the objective of establishing a reference state based on the probable diversity thirty years earlier at the end of the 1980s. A total of 98 points were sampled using a Smith Mac Intyre grab sampler (two replicates each of 0.1 m2 and using a 1 mm mesh sieve). A total of 17,120 individuals representing 840 taxa (including 723 species) were identified from the sampled material. Seven distinct benthic communities were identified as a function of the sediment characteristics. Four diversity indices (Taxonomic Richness, Shannon, Pielou and ES (50) ), and two benthic indices (AMBI and BO2A) were calculated for each of the seven benthic communities. Coastal Terrigenous Mud contains the poorest community while Muddy Detritic supports the richest variety. The Shannon index exceeds 6 at the sampling points with the greater diversity, where the number of individuals per 0.2 m2 reaches 664. Out of 50 organisms collected in a sample, the expected number of species was 35 (ES50). Moreover,