Investigating the Genetic Structure of Three Small Cetacean Species; Tursiops truncatus (Montagu, 1821), Delphinus delphis (Linnaeus, 1758), Phocoena phocoena (Linnaeus, 1758) living in Turkish Waters

There are three most common dolphin and porpoise species, belonging to the order Cetacea, living in Turkish waters; the bottlenose dolphin (Tursiops truncatus), the common dolphin (Delphinus delphis) and the harbour porpoise (Phocoena phocoena). The bottlenose dolphin and common dolphin live in all Turkish waters, whereas the harbour porpoise lives mainly in the Black Sea and it is less common in the Turkish Straits System (TSS) and the Aegean Sea. All these species are threatened by many factors such as bycatch, overfishing, habitat loss, pollution and epidemics. To elaborate efficient conservation management, population structures of these species have been investigated by using genetic techniques worldwide. However, previous genetic studies about these species in Turkey are limited and not sufficient to allow us to understand the population dynamics of the species.

The purpose of the project is to isolate DNA from 253 skin tissues already sampled from the coasts of Turkey in the last 15 years, as well as new samples to be collected by periodic field studies and denunciations, and investigate the genetic structure of species by using mitochondrial DNA (mtDNA) and nuclear DNA (RAD Sequencing) markers. In this way, whether there is more than one population of these species that are genetically differentiated from each other will be investigated and Turkey’s populations will be compared with other populations in the world’s oceans. Besides, nuclear DNA analyses of the Marmara Sea harbour porpoise population, which was isolated from other populations by mtDNA analyses, will be carried out and mtDNA results will be supported by next generation sequencing (RAD-Sequencing) methods. RAD Sequencing has become one of the most commonly used genotyping methods in population genetics studies recently although it has not been used in Turkey to determine the genetic structure of a Cetacean species living in the Turkish Straits System (TSS) and the Aegean Sea until now.

Along with the genetic analyses, the number of samples will be increased through field work in the project area, and a long-term monitoring study on stranded Cetaceans in the western Black Sea will be continued on a monthly basis and a periodic monitoring study will be conducted in the southern coast of the Marmara Sea, and for the first time, in the North Aegean Sea (Saros Bay). It will also be possible to record other marine mammals apart from three targeted species in Saros Bay, an area of high biodiversity, thus a Specially Environmental Protection Area. Besides, the periodic field work in the above area, denunciations will be responded immediately and it is aimed that the sampling area will cover the entire coast of Turkey.

Since genetic studies on bottlenose dolphins have been very limited and there is no genetic study on common dolphins in Turkish waters, investigating the genetic structure of these species by using mtDNA markers as well as next generation RAD sequencing method on nuclear DNA of harbour porpoises with high number of samples, and monitoring stranded marine mammals in Saros Bay (Specially Protected Environment Area) are the original values of this project.

According to the project results, basic data for elaborating conservation strategies for these three Cetacean species, living in Turkish waters and protected by national and international agreements since 1983, will be collected and these data will be utilized for developing subsequent scientific researches. The study and the future molecular studies will contribute to the completion of genetic information on the population structures of Cetacean species living in Turkish waters.

CetaGen is supported by TUBİTAK (financial), İ.Ü. BAP (financial) and TUDAV (vehicle).