New paper on cetaceans' summer abundance and distribution in Bulgarian Black Sea waters
Dear all, On behalf of me and my co-authors, I am happy to share our recently published new paper on cetaceans' summer abundance and distribution in Bulgarian Black Sea waters, available on the link: https://www.acta-zoologica-bulgarica.eu/2024/Suppl_20_21.pdf Abstract: /All three Black Sea cetacean species are nominated as endemic subspecies for the basin listed in the IUCN Red List of Endangered species: the Black Sea harbour porpoise (Phocoena phocoena relicta) and Black Sea bottlenose dolphin (Tursiops truncatus ponticus) as Endangered (EN), while the Black Sea common dolphin (Delphinus delphis ponticus) as Vulnerable (VU). In addition, all three species are protected at national and international levels. Effective conservation of protected and endangered species requires robust data on their distribution to delineate important habitats. We present data on the summer distribution of cetaceans in Bulgarian shelf waters, derived from a series of vessel line transect distance sampling surveys, conducted in the summer months during the period 2020-2023. Harbour porpoise density estimates ranged from 0.156 ind./sq. km (CV=43%) in territorial waters in 2020 to 2.83 ind./sq. km (CV=27%) in deeper waters in 2022. Bottlenose dolphin density estimates ranged from 0.226 ind./sq. km (CV=49%) in territorial waters in 2023 to 0.542 ind./sq. km (CV=35%) in 2020, also in territorial waters. Common dolphin density ranged from 0.032 ind./sq. km (CV=80%) in territorial waters in 2023 to 0.699 ind./sq. km (CV=41%) in deep shelf waters in 2022. The distribution of porpoises has shown a clear preference for deep waters (80-100 m), indicating a shift from the coastal waters that are their preferred habitat in the spring. The density of common dolphin has also shown a gradient towards deeper waters of the shelf, while bottlenose dolphins show a preference for coastal waters. Here, we propose updated threshold values of Descriptor 1's criteria 2 and 4 of the EU Marine Strategy Framework Directive and identify important habitats for harbour porpoises and bottlenose dolphins that remain outside of NATURA 2000's scope./ In case you have any queries, do not hesitate to contact me. Best regards, Dimitar -- __________________________________________________ *__________________________________________________ **Mr. Dimitar Popov**,**PhD **Project Coordinator GREEN BALKANS - Stara Zagora NGO* BSB00432 EOL 30, Boruygrad str. Stara Zagora 6000, Bulgaria Mobile +359 (0)885 108712 E-mail: _dpopov@greenbalkans.org_ http://www.greenbalkans.org __________________________________________________ -- Този имейл е проверен за вируси от антивирусния софтуер Avast. www.avast.com
Dear MARMAM community, We are pleased to share our recent open-access publication about the effectiveness of pingers in bycatch mitigation of the endangered Black Sea harbour porpoise. Popov D, Meshkova G, Dimitrov H, Panayotova M (2026) Can pingers mitigate the bycatch of the endangered Black Sea Harbour Porpoise? Nature Conservation 63: 1-15. https://doi.org/10.3897/natureconservation.63.183768 *Abstract* Incidental catch in fishing gear, mainly in bottom-set gillnets targeting turbot, is a major mortality factor for the Black Sea harbour porpoise (/Phocoena phocoena relicta/), an endangered endemic subspecies of cetacean. Acoustic deterrent devices or pingers are widely used to mitigate bycatch. Between 2019 and 2022, trials using three different pinger models (Future Oceans 10 kHz, Future Oceans 70 kHz, and PAL Wideband) were conducted in Bulgaria during standard turbot fishing operations. The study encompassed a total of 57 hauls. Data was collected by onboard observers (79% of all hauls) and through self-reporting by fishermen. In 61% of all hauls, bycatch was observed, accounting for 189 cetaceans: 182 harbour porpoises, 5 bottlenose dolphins, and 2 common dolphins. No significant difference in bycatch rates between active and control nets (one haul each per trial) was observed in trials involving Future Oceans 10 kHz (17 trials) and 70 kHz (6 trials) pingers (U test, p > 0.05). However, a significant reduction in cetaceans’ bycatch of 74% was recorded during the 6 trials conducted with PAL Wideband pingers (U test, p < 0.05). We therefore recommend PAL as a suitable bycatch mitigation device to Bulgarian authorities and the General Fisheries Commission of the Mediterranean. Best regards, Dimitar Popov -- __________________________________________________ *__________________________________________________ **Mr. Dimitar Popov**,**PhD **Project Coordinator GREEN BALKANS - Stara Zagora NGO* BSB00432 EOL 30, Boruygrad str. Stara Zagora 6000, Bulgaria Mobile +359 (0)885 108712 E-mail: _dpopov@greenbalkans.org_ http://www.greenbalkans.org __________________________________________________
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Dimitar Popov