State Diagnosis of Macrozoobenthic Biodiversity in the Intertidal Zone of the Sandy Coast of Taghazout (Southwestern of Morocco)

The present work is a part of the impact study of the tourist resort "Taghazout Bay" installation on the coast of Taghazout (North of the Agadir bay). The purpose of this study was to assess the initial state of the macrozoobenthic structure present in the intertidal sands at the three study stations over the 2016 and 2017 seasons. The biological approach was accompanied by the study of some physico-chemical parameters of the seawater (temperature, pH, salinity and dissolved oxygen) and the study of the sediment (grading structure, classification, and contents in organic matter). PCA analysis identified a perfect correlation between the physico-chemical parameters. The sediment contains three grading classes only (medium sand, fine sand, and very fine sand), very well classified with normal proportions of organic matter. The study of intertidal benthic macrofauna of the sandy substrate shows ten species and spatiotemporal variations with a clear dominance of the Donax trunculus bivalve species. The authors noticed -from the DIMO model -that the variation profile of the spring and summer (2016 and 2017) shows a community dynamics called "Diversity type". In winter and in autumn, they are known as the "Evenness type". The rank-frequency diagram explains that the benthic community of Taghazout sandy coast exists in the stage "Pioneer 1". The ascending hierarchical clustering gave three logical gatherings of seasons. The faunistic structure of this benthic community revealed the M>C>P shape. The authors also noticed that there is diversity in regimes in this ecosystem.