For marine meta-populations with source-sink dynamics knowledge about genetic connectivity is important to conserve biodiversity and design marine protected areas (MPAs).

This study evaluated genetic connectivity of a Mediterranean endangered species, Pinna nobilis. Using genetics, the authors evaluated phylogeographical patterns in the Western Mediterranean, and in the whole basin using overlapping sequences from the literature. Additionally, the study combined larval trajectories based on oceanographic currents and early life-history traits and 10 highly polymorphic microsatellite loci collected in the Western Mediterranean Sea.

The obtained results provide evidence for high diversity and low inter-population differentiation. Microsatellite genotypes showed increasing genetic differentiation with increased transport time.

Genetic differentiation was detected between Banyuls and Murcia and between Murcia and Mallorca. While no genetic break was detected between the Balearic populations and the mainland. The results show that the Ebro Delta is a larval source for the Balearic populations and that Alicante is a sink population, accumulating allelic diversity from nearby populations.

Alicante is one of the sites most affected by the P. nobilis mass mortality caused by an haplosporidium-like parasite that started in 2016. Therefore, this event supposed not only the loss of some of the densest P. nobilis populations but also some of the most diverse ones. However, the results obtained in the study show that there are other populations with high diversity values in the Tyrrhenian and Sardinian seas. The authors suggest that it would be worth to evaluate if the populations impacted from this mass mortality event are connected with these high diversity ones and could therefore naturally recover.

The authors conclude that the results of the study can be applied in the development of MPA networks in the Western Mediterranean.

Wesselmann et al. (2018) Genetic and oceanographic tools reveal high population connectivity and diversity in the endangered pen shell Pinna nobilis. Scientific Reports 8:4770