(Tursiops truncatus ponticus)
Conservation status:
In Bulgaria: Red book – vulnerable VU [D1]; Biological diversity act – Appendix II and III. International: IUCN Red list – EN (endangered); Bern convention – Appendix II; CITES – Appendix II, Bonn convention – Appendices I and II; Habitats directive 92/43/EEC – Appendices II and IV.
The bottlenose dolphins in the Black Sea are recognized as separate subspecies that differs morphologically from the populations in Atlantic and the Pacific Ocean. The Black sea population is also differentiated genetically from the other populations of the bottlenose dolphin in the eastern and western Mediterranean Sea and the northeast Atlantic Ocean and this evidence confirms the nomination of the subspecies T. t. ponticus.
Distribution:
Practically, it is found in all the oceans and seas on the temperate and tropical latitudes. The Black Sea subspecies is found in the Black Sea, the Kerch strait and the south part of the Sea of Azov and probably (due to lack of genetic evidences) the Sea of Marmara with the Bosphorus and the Dardanelles. There is a series of observations of the bottlenose dolphin entering the big rivers – for example Danube, Dnieper.
The bottlenose dolphins are found in the entire shelf zone of the Black Sea as in some cases they are found far in the open sea. Usually, they gather in large groups during the autumn, winter and spring on comparatively small territory south of Crimea between Sarych cape and Kherson cape.
The migration routes need to be explored in more detail, particularly in the region of the Turkish straits, which serve as the only relation for genetic exchange between the Black Sea and the Mediterranean populations.
Population:
The total number of the population in the Black Sea is unknown. For a larger part of the 20thcentury the bottlenose dolphin is considered to be the lowest number species from the three Black Sea cetaceans.
The estimates of the population size based on line transect surveys in some parts of the Black Sea suggest that the present size of the population is at least several thousand individuals.
Biology and ecology:
The body is dark grey on top and white underneath. The rostrum (beak) is short, the lower jaw – protruding forward. The dorsal fin is big and triangular, arched backwards. The teeth are conic, much bigger than those of the common dolphin. Their number is significantly smaller: 36-52 on each jaw. The bottlenose dolphin is the biggest representative of the cetaceans in the Black Sea, reaching length of up to 3,3 m (usually 1,9-2,5 m) and weight of up to 300 kg. Lifespan is up to 25-30 years, but has comparatively low fertility. The females become sexually mature at the age of 5-6 years or even later and the males at the age of 8-12 years.
The breeding season is year-long as the most active periods are the spring and the early summer. The pregnancy lasts 12 months and most often gives birth to one infant. The period of birth is from 2-3 to 6 years. The lactation period is 4-18 months. These reproduction characteristics of the bottlenose dolphins seem to be the main natural factor limiting the increase of the population.
The bottlenose dolphins are mainly piscivorous in the Black Sea, feeding on benthic species as well as pelagic species with different sizes. 16 species of fishes in total are described as plunder on the Crimean and Caucasian shores: turbot (Psetta maxima maeotica), thornback ray (Raja clavata), whiting (Merlangius merlangus euxinus), golden grey mullet (Liza aurata), leaping mullet (Liza saliens), flathead grey mullet (Mugil cephalus), anchovy (Engraulis encrasicolus ponticus), red mullet (Mullus barbatus ponticus), bonito (Sarda sarda), black scorpion fish (Scorpaena porcus), corb (Umbrina cirrosa). Within the last years the introduced species far-east mullet (Mugil soiuy) is an important food resource in the Northern Black Sea in Crimean waters. The daily consumption is 6-32 kilos.
Threats:
After the total prohibition on commercial killing of cetaceans in the Black Sea from 1983, the main threat to the species caused by human activity is the bycatch (accidental entanglement in fishing nets) mainly caused by turbot fishery.
Conservation status:
In Bulgaria: Red book – vulnerable VU [D1]; Biological diversity act – Appendix II and III. International: IUCN Red list – EN (endangered); Bern convention – Appendix II; CITES – Appendix II, Bonn convention – Appendices I and II; Habitats directive 92/43/EEC – Appendices II and IV.
The bottlenose dolphins in the Black Sea are recognized as separate subspecies that differs morphologically from the populations in Atlantic and the Pacific Ocean. The Black sea population is also differentiated genetically from the other populations of the bottlenose dolphin in the eastern and western Mediterranean Sea and the northeast Atlantic Ocean and this evidence confirms the nomination of the subspecies T. t. ponticus.
Distribution:
Practically, it is found in all the oceans and seas on the temperate and tropical latitudes. The Black Sea subspecies is found in the Black Sea, the Kerch strait and the south part of the Sea of Azov and probably (due to lack of genetic evidences) the Sea of Marmara with the Bosphorus and the Dardanelles. There is a series of observations of the bottlenose dolphin entering the big rivers – for example Danube, Dnieper.
The bottlenose dolphins are found in the entire shelf zone of the Black Sea as in some cases they are found far in the open sea. Usually, they gather in large groups during the autumn, winter and spring on comparatively small territory south of Crimea between Sarych cape and Kherson cape.
The migration routes need to be explored in more detail, particularly in the region of the Turkish straits, which serve as the only relation for genetic exchange between the Black Sea and the Mediterranean populations.
Population:
The total number of the population in the Black Sea is unknown. For a larger part of the 20thcentury the bottlenose dolphin is considered to be the lowest number species from the three Black Sea cetaceans.
The estimates of the population size based on line transect surveys in some parts of the Black Sea suggest that the present size of the population is at least several thousand individuals.
Biology and ecology:
The body is dark grey on top and white underneath. The rostrum (beak) is short, the lower jaw – protruding forward. The dorsal fin is big and triangular, arched backwards. The teeth are conic, much bigger than those of the common dolphin. Their number is significantly smaller: 36-52 on each jaw. The bottlenose dolphin is the biggest representative of the cetaceans in the Black Sea, reaching length of up to 3,3 m (usually 1,9-2,5 m) and weight of up to 300 kg. Lifespan is up to 25-30 years, but has comparatively low fertility. The females become sexually mature at the age of 5-6 years or even later and the males at the age of 8-12 years.
The breeding season is year-long as the most active periods are the spring and the early summer. The pregnancy lasts 12 months and most often gives birth to one infant. The period of birth is from 2-3 to 6 years. The lactation period is 4-18 months. These reproduction characteristics of the bottlenose dolphins seem to be the main natural factor limiting the increase of the population.
The bottlenose dolphins are mainly piscivorous in the Black Sea, feeding on benthic species as well as pelagic species with different sizes. 16 species of fishes in total are described as plunder on the Crimean and Caucasian shores: turbot (Psetta maxima maeotica), thornback ray (Raja clavata), whiting (Merlangius merlangus euxinus), golden grey mullet (Liza aurata), leaping mullet (Liza saliens), flathead grey mullet (Mugil cephalus), anchovy (Engraulis encrasicolus ponticus), red mullet (Mullus barbatus ponticus), bonito (Sarda sarda), black scorpion fish (Scorpaena porcus), corb (Umbrina cirrosa). Within the last years the introduced species far-east mullet (Mugil soiuy) is an important food resource in the Northern Black Sea in Crimean waters. The daily consumption is 6-32 kilos.
Threats: