Is there a distinct harbor porpoise subpopulation in the Marmara Sea?

Abstract

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.

Keywords:

• Management unit
• Mitochondrial DNA
• Phocoena phocoena
• Population genetics
• Turkish Straits System

Acknowledgments

We would like to thank Hakkı Bayar and the volunteers for field surveys; IU/TUDAV Cetacean Stranding Network for notifications; Evrim Kalkan for help with the labwork.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding information

This study was supported by a grant (No: 11Y00P2) from the Research Fund of Boğaziçi University in Istanbul to RB and partly by the EC Seventh Framework Program (FP7/2007–2013) under Grant Agreement No. 287844 for the project “Towards COast to COast NETworks of marine protected areas (from the shore to the high and deep sea), coupled with sea-based wind energy potential” (CoCoNET) Project.