Spatial genetic structure in the saddled sea bream (Oblada melanura [Linnaeus, 1758]) suggests multi-scaled patterns of connectivity between protected and unprotected areas in the Western Mediterranean Sea

Abstract

Spatial genetic structure in the saddled sea bream (Oblada melanura [Linnaeus, 1758] a b s t r a c tMarine protected areas (MPAs) and networks of MPAs are advocated worldwide for the achievement of marine conservation objectives. Although the knowledge about population connectivity is considered fundamental for the optimal design of MPAs and networks, the amount of information available for the Mediterranean Sea is currently scarce. We investigated the genetic structure of the saddled sea bream (Oblada melanura) and the level of genetic connectivity between protected and unprotected locations, using a set of 11 microsatellite loci. Spatial patterns of population differentiation were assessed locally (50-100 km) and regionally (500-1000 km), considering three MPAs of the Western Mediterranean Sea. All values of genetic differentiation between locations (Fst and Jost's D) were non-significant after Bonferroni correction, indicating that, at a relatively small spatial scale, protected locations were in general well connected with non-protected ones. On the other hand, at the regional scale, discriminant analysis of principal components revealed the presence of a subtle pattern of genetic heterogeneity that reflects the geography and the main oceanographic features (currents and barriers) of the study area. This genetic pattern could be a consequence of different processes acting at different spatial and temporal scales among which the presence of admixed populations, large population sizes and species dispersal capacity, could play a major role. These outcomes can have important implications for the conservation biology and fishery management of the saddled sea bream and provide useful information for genetic population studies of other coastal fishes in the Western Mediterranean Sea.

Population genetic structure of the European lobster ( Homarus gammarus ) in the Irish Sea and implications for the effectiveness of the first British marine protected area

“…Samples collected outside of the Lundy NTZ reported similar levels of genetic diversity to the Lundy NTZ sample, which is also compatible with a lack of isolation for the Lundy NTZ. Calò et al (2016) reported similar levels of genetic diversity for protected and unprotected areas in the saddled sea bream (Oblada melanura). This pattern differs from the study including two MPAs in the western Mediterranean by Pérez-Ruzafa et al (2006) that reported higher values of total and standardised allelic richness in protected populations of Diplodus sargus than in unprotected ones.…”

Juvenile fish assemblages in temperate rocky reefs are shaped by the presence of macro-algae canopy and its three-dimensional structure

“…In the case of marine fishes, previous studies have highlighted the importance of these various spatial scales. In the Mediterranean, some studies highlighted the importance of the dispersal capacities of fishes at the egg, larval, juvenile and recruit stages 5 – 7 . Regarding habitat characteristics, complex habitats formed by macrophytes have been proved to host more abundant and/or more diversified communities compared to simpler habitats 8 .…”

Genetic variation in Irish Sea brown crab (Cancer pagurusL.): implications for local and regional management

“…Calo et al . (2016) also reported similar levels of genetic diversity for protected and unprotected areas in the saddled sea bream ( Oblada melanura ). While we do not have samples from before the commencement of commercial harvesting or during the initial stages of exploitation when loss of diversity may be most pronounced (Ryman et al ., 1995) and thus cannot rule out the possibility that some genetic variation has been lost due to fishing, the results indicate that high levels of genetic variation are maintained within the species which is fundamental for maintaining sustainable yields and adaptability of populations (Kenchington et al ., 2003).…”