Volume 44 - Issue 2 - 185 - 192

Dolphins Inhabiting in Black Sea and Effects of Fisheries

Karadeniz’de Yaşayan Yunus Türleri ve Balıkçılığa Etkileri

Dolphins are the most important members of the marine mammals which undergo a decrease in population for many reasons such as overfishing, habitat degradation, maritime / traffic and pollution. Biodiversity in the Black Sea is low mostly due to the geographical isolation and low salinity, high hypoxic amount and anoxic bottom waters of 100-250 m depth as well. Therefore, only the three dolphin species; the harbour porpoise (Phocoena phocoena), common dolphin (Delphinus delphis) and bottlenose dolphin (Tursiops truncatus) live in the Black Sea region. This study is about harbor porpoise, short-beaked dolphin and bottlenose dolphin living in the Black Sea . The results of the scientific researches and publications focusing on these species are scanned and gathered together. The biological characteristics, ecological requirements and habitats of these species are reviewed, effect on both ecosystem and fisheries are evaluated. Many species of the marine mam- mals are negatively effected by anthropogenic factors and as a result given in the Red List” by the the World Conservation Union (IUCN) where; Delphinus delphis is stated as least compromised (LC), he Mediterranean sub-population is stated as endangered (EN), Phocoena phocoena is stated as least compromised (LC), Tursiops truncatus is stated as least compromised (LC) and Mediterranean subpopulation of Tursiops truncatus is stated as sensitive (VU). Unintentional catch of dolphins, mostly resulting in death or killing of these species, by turbot nets having 280-360 mm mesh size is one of the leading anthropogenic factors. Besides, dolphins’ stealing fish particularly from the bottom gillnets with 32-44 mm mesh size and destroying these nets have a negative impact on fishing. In many parts of the world, many studies were perfomed to prevent unintentional catch (bycatch) of the dolphins and to keep away the dolphins from the nets in order to prevent fish stealing (depredation) and damaging of the nets. Studies have also been carried on focusing on the unintentional catch (bycatch) of dolphins in the Black Sea region, however researches particularly on acoustic dolphin repellents are very limited. 

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