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Disentangling the impact of Late Quaternary climate change from human activities can have crucial implications on the conservation of endangered species. We investigated the population genetics and demography of the Mediterranean monk seal (Monachus monachus), one of the world's most endangered marine mammals, through an unprecedented dataset encompassing historical (extinct) and extant populations from the eastern North Atlantic to the entire Mediterranean Basin. We show that Cabo Blanco (Western Sahara/Mauritania), Madeira, Western Mediterranean (historical range) and Eastern Mediterranean regions segregate into four populations. This structure is probably the consequence of recent drift, combined with long-term isolation by distance (R2 = 0.7), resulting from prevailing short-distance (less than 500 km) and infrequent long-distance dispersal (less than 1500 km). All populations (Madeira especially), show high levels of inbreeding and low levels of genetic diversity, seemingly declining since historical time, but surprisingly not being impacted by the 1997 massive die-off in Cabo Blanco. Approximate Bayesian Computation analyses support scenarios combining local extinctions and a major effective population size decline in all populations during Antiquity. Our results suggest that the early densification of human populations around the Mediterranean Basin coupled with the development of seafaring techniques were the main drivers of the decline of Mediterranean monk seals. [ABSTRACT FROM AUTHOR]

The recent invasion of the lionfish Pterois miles to the Mediterranean draws major concerns to the fate of the indigenous ecosystem, based on previous knowledge of the species' detrimental capabilities as an introduced species in the Western Atlantic Ocean. In order to determine invasive patterns in the Eastern Mediterranean, we compared the genetic divergence of two mtDNA markers, the COI and D-loop, between and within the introduced Levantine and native range Red Sea populations of the lionfish. COI region presented a remarkably shallow genealogy, and both genes have failed to show a definite geographic population structure, with non-significant AMOVA and low pairwise FST values. A shared haplotype across all localities in the D-loop provided probable confirmation for the Red Sea origin of the invasive population, and a number of introduced haplotypes indicated that the Mediterranean populations are a product of multiple invasion events. Finally, we observed large haplotype diversity in the Red Sea samples that were absent from the introduced localities, implying a possible future enforcement to the invasive genetic pool in the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

Genetic population structure of geographically isolated endangered Black Sea harbor porpoise (Phocoena phocoena relicta) is little known in Turkish waters, especially in the Turkish Straits System (TSS- Marmara Sea, Bosphorus and Dardanelles), which connects the Black Sea and the Aegean Sea. Mitochondrial DNA sequences of 70 new individuals sampled in the Turkish Black Sea, TSS and Aegean Sea, revealed five new haplotypes from the Black Sea. The findings support the idea that harbor porpoises from the Black Sea dispersed into the Aegean through the TSS. Considering signatures of population expansion, all subpopulations showed a signature of population expansion. The network data and the Фst calculations indicated that the Marmara Sea subpopulation was significantly differentiated from all of the other subpopulations, and supports the notion of its isolated. The finding of a potential management unit (MU) within an already heavily impacted subpopulation as a whole suggests that the individuals of P. p. relicta inhabiting the Marmara Sea require a very rigorous conservation strategy to ensure the survival of this subpopulation, represented by its unique haplotype. [ABSTRACT FROM AUTHOR]