Evaluation biométrique de la fausse patelle (Siphonaria pectinata )(Linnaeus,1758) issue de deux sites contrastés de la côte Mostaganémoise

Abstract

The study deals with a biometric analysis of the evolution of the shell as well as the total weight of a species bioindicator "Siphonaria pectinata", the main objective of this study is the evaluation of the resistance of the latter, resulting from contrasting sites of the western Algerian coastline precisely at the Mostaganémoise coast (Mostaganem harbor (PM) and, the site of Stidia (STD)), but also to decide on its profile because it remains until then little known because no study does not was dedicated. The work consists in a follow-up during 3 months of sampling of the biometric indices of 360 individuals of this Gastropod Mollusk namely: the height of the shell (H), the length (L) the width (La), previous vertex (Sa), posterior vertex (Sp) as well as the total weight (Pt) are performed for all populations of S.pectinata. The correlation of the different measures (length-height, length-width, lengthtotal weight, total height-weight, width-total weight, posterior vertex-vertex anterior) was treated and analyzed following the power curves of the form y = axb and following the test "t" STUDENT which testify on the whole of the sites but also months of work (February, March, and April) of a minor allometry on the combinations of the parameters carried out. the results reveal the development of its shell in height first and width second, followed by the length, the total weight parameter finally takes the last place by entering the longest growth speed compared to the three preceding parameters (L, La, H) and those for both study sites. The previous vertex grows more slowly than the posterior vertex. These results confirm that the growth of this mollusc varies and depends on several biotic and abiotic factors that also condition shell development and Siphonaria weight growth. This approach is a good means of environmental assessment that could be used in biomonitoring programs.