Green Balkans NGO efforts to monitor the dynamics and variation of cetaceans’ abundance and distribution in Bulgarian territorial waters continued with an autumn survey. It was carried out in the second part of October starting on 18 and after two temporary terminations due to bad weather conditions was completed on 31.
The standard technique of distance sampling along line transects was used once again. The survey used the same design as two previous ones undertaken in June 2017 and 2018 including 13 transects with total length of 458 km on effort ensuring coverage of 7% on study area. Main limiting factor for the successful execution of the survey was meteorological conditions at sea as for the visual observations were needed good conditions – low wind and waves. After the start of the survey and covering in 3 days 6 of planned transects, we had to interrupt due to bad weather conditions. We continued 5 days later when the sea calmed down and managed to complete 4 more transects in 2 days. Then we had to make one more pause of 3 days before finishing with last 3 transects on 31 October – The International Black Sea Action Day!
The survey team successfully covered 420.7 km on effort from the planned transects during favourable weather conditions within 6 days of effort. During the survey, the observers recorded 67 sightings in total with 203 individuals. Unlike previous surveys this time the most numerous were encounters of Black sea common dolphins (Delphinus delphis ponticus) – 29. Black sea bottlenose dolphins (Tursiops truncatus ponticus) were second with 19 sightings while Black sea harbor porpoises (Phocoena phocoena relicta) was observed on only 18 occasions. In 1 of the sightings species wasn’t identified.
The current survey is the third one organized by Green Balkans NGO deploying the same design in order to monitor trend in distribution, density and abundance of cetaceans in Bulgarian territorial waters. This time the effort was lowest – 420.7 km of line transects compared to 424 km last June and 441 km earlier this year. This year the number of sightings in autumn was higher – 67 compared to spring – 55. Largest encounter group was of Common dolphins numbering 35 ind.
Collection of information on distribution and abundance of cetaceans is important for conservation of these enigmatic species. Data from the survey will be analyzed so to get an estimation of abundance for different species in the relevant season.
We would like to thank volunteers Galina Meshkova, Polina Hristova, Teodora Ilieva and Antonia Miteva who have proven as experience observers once again and allowed continuity of the study. Special thanks to captain Georgiev with “Kaliakria” yacht for ensuring the optimal survey conditions on board.
The survey was made possible thanks to the generous funding provided by OceanCare (www.oceancare.org).
Contacts:
Dimitar Popov - Green Balkans NGO
mob. number: +359885108712, e-mail: dpopov@greenbalkans.org
The standard technique of distance sampling along line transects was used once again. The survey used the same design as two previous ones undertaken in June 2017 and 2018 including 13 transects with total length of 458 km on effort ensuring coverage of 7% on study area. Main limiting factor for the successful execution of the survey was meteorological conditions at sea as for the visual observations were needed good conditions – low wind and waves. After the start of the survey and covering in 3 days 6 of planned transects, we had to interrupt due to bad weather conditions. We continued 5 days later when the sea calmed down and managed to complete 4 more transects in 2 days. Then we had to make one more pause of 3 days before finishing with last 3 transects on 31 October – The International Black Sea Action Day!
The survey team successfully covered 420.7 km on effort from the planned transects during favourable weather conditions within 6 days of effort. During the survey, the observers recorded 67 sightings in total with 203 individuals. Unlike previous surveys this time the most numerous were encounters of Black sea common dolphins (Delphinus delphis ponticus) – 29. Black sea bottlenose dolphins (Tursiops truncatus ponticus) were second with 19 sightings while Black sea harbor porpoises (Phocoena phocoena relicta) was observed on only 18 occasions. In 1 of the sightings species wasn’t identified.
The current survey is the third one organized by Green Balkans NGO deploying the same design in order to monitor trend in distribution, density and abundance of cetaceans in Bulgarian territorial waters. This time the effort was lowest – 420.7 km of line transects compared to 424 km last June and 441 km earlier this year. This year the number of sightings in autumn was higher – 67 compared to spring – 55. Largest encounter group was of Common dolphins numbering 35 ind.
Collection of information on distribution and abundance of cetaceans is important for conservation of these enigmatic species. Data from the survey will be analyzed so to get an estimation of abundance for different species in the relevant season.
We would like to thank volunteers Galina Meshkova, Polina Hristova, Teodora Ilieva and Antonia Miteva who have proven as experience observers once again and allowed continuity of the study. Special thanks to captain Georgiev with “Kaliakria” yacht for ensuring the optimal survey conditions on board.
The survey was made possible thanks to the generous funding provided by OceanCare (www.oceancare.org).
Contacts:
Dimitar Popov - Green Balkans NGO
mob. number: +359885108712, e-mail: dpopov@greenbalkans.org
