Morphological and genetic characterization of the sharpsnout seabream populations (Diplodus puntazzo, Sparidae) along a boundary area between the two Mediterranean basins

ABSTRACT

In order to test the potential ecological role of the Siculo-Tunisian Strait as a geographic barrier, the morphological and genetic variation of eight Tunisian samples of the sharpsnout seabream, Diplodus puntazzo, were studied, based on 23 truss network elements and 13 polymorphic allozyme loci. Significant morphological differences were observed between studied samples, especially between lagoon ones. Although genetic data did not support the detected morphometric variation, F-statistics indices (F_IS and F_ST) revealed a significant departure from panmixia with heterozygote deficiencies and slight genetic differentiation between samples. Genetic results suggested the existence of moderate and local genetic heterogeneity that can be explained by the chaotic genetic patchiness hypothesis. Morphological and genetic results showed that the Siculo-Tunisian Strait does not seem to act as a barrier limiting the connectivity between the natural populations of D. puntazzo, at least at the scale of the Tunisian coast. Thus, the phenotypic variation identified in this study appears to be environmentally induced through the exploitation of different ecological niches and hydrodynamic constraints.

RESPONSIBLE EDITOR:

• Gavin Gouws

KEYWORDS:

• Allozyme
• Diplodus puntazzo
• Siculo-Tunisian Strait
• Sparidae
• truss network
• Tunisian coast

Acknowledgements

The authors are grateful to two anonymous reviewers and the Editorial Office who provided valuable suggestions and comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by a grant from the Tunisian Ministry of Higher Education, Scientific Research and Technology.