Strong invasion of Mellah lagoon (South-Western Mediterranean) by the American blue crab Callinectes sapidus Rathbun, 1896.

Based on our discussions with fishermen and analysis of catches from professional fishing, this work confirms the presence of the American blue crab Callinectes sapidus in the southwest Mediterranean and highlights its invasion of Mellah lagoon in Algeria. The number and frequency of occurrence of this species in fishing gear (up to 10 individuals per fyke net), the presence of juveniles and ovigerous females as well as its presence in the local market, show that it is well established. The possible impact of C.

From depth to regional spatial genetic differentiation of Eunicella cavolini in the NW Mediterranean.

Connectivity studies in the marine realm are of great importance to understand the evolutionary potential of populations in a context of growing pressures on the marine environment. Here, we investigated the effect of the local, regional, and depth spatial scale on the population genetic structure of the yellow gorgonian Eunicella cavolini, one of the most common octocoral species of the Mediterranean hard-bottom communities. This species, along with other sessile metazoans typical of coralligenous ecosystems, plays an important role in supporting biodiversity, but is also impacted by direct and indirect consequences of human activities, such as physical destruction or mortality events due to thermal anomalies.

Contrasted levels of genetic diversity in a benthic Mediterranean octocoral: Consequences of different demographic histories?

Understanding the factors explaining the observed patterns of genetic diversity is an important question in evolutionary biology. We provide the first data on the genetic structure of a Mediterranean octocoral, the yellow gorgonian , along with insights into the demographic history of this species. We sampled populations in four areas of the Mediterranean Sea: continental France, Algeria, Turkey, and the Balearic and Corsica islands.

Microsatellite length variation in candidate genes correlates with habitat in the gilthead sea bream Sparus aurata.

The genetic basis and evolutionary implications of local adaptation in high gene flow marine organisms are still poorly understood. In several Mediterranean fish species, alternative migration patterns exist between individuals entering coastal lagoons that offer favourable conditions for growth and those staying in the sea where environmental conditions are less subject to rapid and stressful change. Whether these coexisting strategies are phenotypically plastic or include a role for local adaptation through differential survival needs to be determined.

[Strong genetic differentiation of the gilthead sea bream Sparus aurata (L., 1758) between the two western banks of the Mediterranean].

We characterised four samples of gilthead sea bream from the two western Mediterranean banks with three microsatellite loci and two RAPDs systems. Contrarily to what could be predicted for a highly mobile species with a planktonic larval dispersal phase, we observed a strong and significant genetic differentiation at all loci between the two banks (F(st)=0.069(***)), whereas two samples from the Gulf of Lions were almost identical (F(st)=0.