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    Population genetic structure of the short-beaked common dolphin from the Black Sea and the Turkish Straits System
    (Taylor & Francis Ltd, 2020) Tonay, Arda M.; Uzun, Begum; Dede, Ayhan; Ozturk, Ayaka Amaha; Danyer, Erdem; Danyer, Isil Aytemiz; Bilgin, Sabri
    Our study aims to assess the population connectivity, evolutionary history, and conservation status of the short-beaked common dolphin in the Black Sea and Turkish Straits System (TSS). We also include DNA sequences from the Atlantic Ocean and the Mediterranean Sea to provide a regional perspective to our localized study. Analysis of 366 base pairs of mitochondrial DNA D-loop fragments from 37 samples collected from short-beaked common dolphins in the Black Sea, TSS, and Aegean Sea revealed 13 haplotypes, eight of which have not been previously reported. While analysis of samples archived on GenBank revealed 89 different haplotypes across the region. The haplotype network contains two main peripheral groups that include individuals from all locations. Haplotypes from the Atlantic Ocean are scattered across the network and no obvious population separation was detected. Some shared haplotypes potentially indicate multi-directional colonization events of the Mediterranean Sea from the eastern Atlantic Ocean. Moreover, some less widely distributed haplotypes suggest some level of more recent genetic connectivity through the Strait of Gibraltar and the TSS and point out the importance of these straits in the dispersal of short-beaked common dolphins. The haplotype and nucleotide diversity values were lower in the Black Sea, TSS, and western Mediterranean Sea when compared to the Atlantic Ocean, supporting the expansion of Atlantic populations into the Mediterranean and the Black Seas. Differentiation was observed between the Atlantic Ocean, and the Mediterranean Sea, TSS and the Black Sea based on CYRILLIC CAPITAL LETTER EFst but not between Mediterranean and the Black Seas. For common dolphins, which have high dispersal potential, the protection of open seas and narrow seaways to enhance connectivity may be crucial.
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    Seasonal and diel patterns in Black Sea harbour porpoise acoustic activity in 2020-2022
    (Wiley, 2024) Ivanchikova, Julia; Tregenza, Nick; Popov, Dimitar; Meshkova, Galina; Paiu, Romulus-Marian; Timofte, Costin; Ozturk, Ayaka Amaha
    The Black Sea is a semi-enclosed inland sea with an unevenly distributed extensive coastal shelf area and anoxic deep waters. It is inhabited by common and bottlenose dolphins, as well as harbour porpoises, all represented by local subspecies. Between September 2020 and October 2022, 19 F-PODs deployed by research teams from Bulgaria, Georgia, Romania, T & uuml;rkiye and Ukraine collected data on acoustic activity of Black Sea harbour porpoises. Strong seasonal and diel patterns were found, which varied in three regions. In the south-eastern part of the Black Sea, harbour porpoise acoustic activity was higher from January to May, with a peak in April. This pattern agrees with the seasonal anchovy migration from the winter spawning grounds in warmer waters in the south-eastern region to feeding grounds on the productive shallow north-west shelf. The diel pattern showed strong nocturnal acoustic activity, which is consistent with anchovy vertical migration. Porpoises on the western side of the Black Sea exhibited a bimodal seasonal pattern in acoustic activity, with a larger peak in April and a smaller one in October. Diel activity was primarily nocturnal. On the north-west shelf, harbour porpoise acoustic activity was mostly recorded during the warm period from April to October. The diel pattern showed activity mainly during daylight with two peaks: a smaller one approximately at dawn and a larger one at dusk. This pattern is similar to the vertical migrations of sprat. Overall, the results of the study were consistent with the prey being an important driver of seasonal and diel dynamics of harbour porpoise acoustic activity. Acoustic activity of harbour porpoises showed strong seasonal and diel patterns on the whole Black Sea basin scale. Patterns differ in different regions and show higher activity in the South and East during winter and higher activity in the Northwest during summer. These patterns could be driven by seasonal and vertical migrations of the main prey species, as well as other factors.image