Résumé:
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.
