Cytochrome c oxidase subunit I variability in Ruditapes decussatus (Veneridae) from the western Mediterranean

D Sanna,T Lai,P Cossu,F Scarpa,G L Dedola,B Cristo,P Francalacci,M Curini-Galletti,L Mura,N Fois,F Maltagliati,M Casu

doi:10.1080/24750263.2017.1395914

Abstract

Ruditapes decussatus (Linnaeus, 1758) (Veneridae) is an Atlanto-Mediterranean bivalve whose populations have experienced reductions and, in some instances, hybridisation with allochthonous R. philippinarum. Acquisition of additional genetic knowledge concerning the present R. decussatus populations is essential to address adequate conservation plans for this species. For this purpose, we analysed a portion of the mtDNA cytochrome c oxidase subunit I (COI) region in populations from the western Mediterranean, where this species represents a harvested fishery resource. Our analyses revealed an overall lack of genetic structure within the western Mediterranean area, and the occurrence of mtDNA substructuring between the Aegean and Marmara seas and the remaining populations from the whole Mediterranean basin and the South European Atlantic coast. The results obtained for populations from Sardinia, where extensive restocking programmes have not been reported and where R. philippinarum is rare and localised, suggest that intensive harvesting and potential dispersal alone may have been able to shape the genetic variation identified in the local R. decussatus populations.

Highlights

The grooved carpet shell, Ruditapes decussatus (Linnaeus, 1758) (Veneridae), is a bivalve mollusc that inhabits muddy-sandy sediments along the Mediterranean and Eastern Atlantic shallow coastal areas (Fischer-Piette & Métivier 1971)
We investigated the level of mtDNA genetic variability in R. decussatus populations from undersampled regions of the western Mediterranean, where the species is an important marine fishery resource
Emre Keskin, all Turkish sequences used in this study were from Marmara Sea (MAR)

Summary

Introduction

The grooved carpet shell, Ruditapes decussatus (Linnaeus, 1758) (Veneridae), is a bivalve mollusc that inhabits muddy-sandy sediments along the Mediterranean and Eastern Atlantic shallow coastal areas (Fischer-Piette & Métivier 1971) This species is gonochoric with external fertilisation and planktotrophic larval stages. The high commercial demand for R. decussatus led to intensive exploitation in several areas and, as a consequence, natural R. decussatus populations have declined in many European and Mediterranean sites (http:// www.fao.org/fishery/culturedspecies/Ruditapes_ decussatus/en). This species is further threatened by the introduction of the Manila clam (Ruditapes philippinarum), native to the West Pacific coasts, into Europe in the early 1970s (see Breber 2002, and references therein). Competition between the two species led to dramatic reductions in R. decussatus populations in many geographic areas (see e.g. Pranovi et al 2006; Juanes et al 2012; Bidegain & Juanes 2013), and, in some instances, hybridisation was observed between the two species (Hurtado et al 2011; Habtemariam et al 2015)

Methods

Results

Conclusion