Morphometric Variation of Fishery Exploited Muricidae Hexaplex trunculus in the Mediterranean Sea and the Northeastern Atlantic Ocean: Implications for Stock Identification
Morphological studies of species with wide distribution range and high commercial value, such as the banded murex Hexaplex trunculus (Linnaeus, 1758) provide information on stock structure, which is the basis for understanding fish population dynamics and enable resource assessment for fisheries management. In the present study, we examined morphological variation among Atlantic and Mediterranean populations of H. trunculus using multivariate analysis. Our results supported the existence of four distinguishable stocks (Atlantic, Alboran, Western Mediterranean and Eastern Mediterranean) correctly classified 71.7% of specimens, and indicated significant degrees of variation in morphometric characteristics between regions. Examination of the contribution of each morphometric variable to the principal components and canonical functions indicated that differences among samples seemed to be associated with the shell and aperture length and width. Samples from the Atlantic Ocean and the Alboran Sea had the largest shell size and the greatest morphometric divergence. This strong morphometric differentiation appears to be associated with local environmental factors (exposure on the rocky shores, food availability and predation) and oceanographic current barriers.