An ecological study on the distribution of the fan shell Pinna nobilis Linnaeus, 1758 (Mollusca: Bivalvia) in the western Algerian coasts.

Based on the fact that the Mediterranean sea is an existing place to the bi-valves fan mussels of Pinna nobilis, the aim of this introductory study is to focus on understanding the nature of P.nobilis population density and its structure with an ongoing purpose to encourage future investigation of the subject matter to successfully uncover more ecological models; in order to reach the latter, a fieldwork took place from 2015 to 2018 in the Algerian west coasts on multiple sites with an end goal of better understanding the dynamics of the species, as well as assessing the effectiveness of protective measures of P.nobilis on the Algerian Western coastlines. The density, population structure and the growth of individuals noted on P.nobilis were examined through scuba diving along with multiple transects on the west coast of Algeria and measurements were executed on different spatial scales in populations occupying different sites; one of, is that of the protected naval area of "Habibas Island" in addition to other unprotected ones.. The results varied and they are as follows: the density of P. nobilis ranged from 0.28 in /m-2 on the transect to 0.08 in /m-2. The measured individuals were certainly a representative of their environment. The size of the P.nobilis did not prove itself to be prominent disturbance in the structure of the associated biota; the latter however showed that it was influenced by different areas. The outcomes of the study state that the recovery of the P. nobilis population on the west coast of Algeria was highlighted; stating the urgent need for setting security and protection of these species located on the Algerian West Coast