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Summer expedition to study dolphins and birds in the Black Sea

Team of observers
03.08.2021
In the period July 27 - August 1, the Green Balkans' summer expedition was held to study the populations of seabirds and cetaceans in the Bulgarian territorial waters of the Black Sea. It is part of the program of the organization for research and conservation of cetaceans in our sea, within which such expeditions are regularly carried out for the fifth consecutive year. The purpose of these studies is to fill the lack of data on these marine inhabitants to assess the status of their populations and the introduction of adequate and effective measures for their protection.

One of the most delicate moments in the planning of any expedition is the consideration of the meteorological situation and especially the wind, which, unlike on land, is rarely absent in the sea. This sometimes necessitates the interruption of navigation due to the deterioration of the sea state, which leads to the impossibility of making observations, or moving to another section of the coast with more suitable conditions. All this, coordinated every minute with the captain of the vessel and the crew, makes it possible to conduct the expedition as compactly as possible, in the shortest possible time. And this is one of the very important things for the subsequent analysis of the data.

During this expedition, the Green Balkans team on board a vessel, the yacht Kaliakria, sailed a total of 440 km of transects. 72 sightings of dolphins were recorded with a total of 211 individuals, of which 46 were harbour porpoises, 17 bottlenose dolphins, 8 common dolphins, and one unidentified species of dolphin. In general, the ratio between the three species is similar to that during spring expeditions. The uneven distribution of the species, the food migrations of porpoises along the southern coast, as well as the larger and more spectacular groups of bottlenose dolphins with about 20 individuals and the common dolphins with 13 individuals made an impression.

The results are lower for birds compared to previous expeditions. Most observations were recorded on the species of little gull (Larus minutus). And among the more interesting observations are those of feeding parasitic jaegers, whose behavior of chasing and stealing the prey of terns and gulls is quite spectacular, a group of yelkouan shearwaters (Puffinus yelkouan), which are less common in the Black Sea during the summer, and also the associated behavior of feeding gulls and dolphins.

Contacts:
Dimitar Popov - dpopov@greenbalkans.org