Characterisation of genetic structure of Dicentrarchus labrax larvae in two nurseries of the Gulf of Lions (NW Mediterranean)

¹ Université Montpellier II, Institut des Sciences de l'Evolution de Montpellier, Biologie intégrative, UMR CNRS 5554, place E. Bataillon, cc63, 34095 Montpellier Cedex 5, France
² École Pratique des Hautes Études, Station Méditerranéenne de l'Environnement Littoral, quai de la Daurade, 34200 Sète, France
³ Hellenic Centre for Marine Research, Institute of Marine Biology and Genetics, PO Box 2214, Gournes Pediados, 71500 Heraklion, Crete, Greece

Corresponding author: bruno.guinand@univ-montp2.fr

Received: 19 October 2007
Accepted: 1 February 2008

Abstract

Despite extensive knowledge of the genetic structure of sea bass (Dicentrarchus labrax) populations, no studies have investigated genetic structure within early life stages, or compared such structure between such stages and (sub)adults. Using nine newly developed microsatellite loci, we investigated patterns of genetic variation and relatedness among juveniles that settled in two NW Mediterranean nursery grounds in close geographical proximity. There was no evidence for differentiation among samples at settlement (θ = -0.0010), and no significant genetic relatedness. Nevertheless, significant departures from Hardy-Weinberg equilibrium were detected in each sample, which could not be attributed exclusively to the presence of null alleles and to Wahlund effect. These results are compared with and discussed in relation to the genetic structure of adults described in the same area 10 years ago.