DATA ON CETACEAN MORTALITY ALONG BULGARIAN BLACK SEA COAST DURING SPRING-AUTUMN 2016
VIOLETA EVTIMOVA1, KRASTIO DIMITROV2* , VENCESLAV DELOV1, YANA VELINA3,
STOYAN IORDANOV1
1 – Department of Zoology and anthropology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria
2 – Department of Ecology and EP, Faculty of Biology, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria
3 – Ministry of Environment and Water, Sofia, Bulgaria
* Corresponding author: krastiodimitrov@gmail.com
Keywords: Phocoena phocoena, Tursiops truncatus, Delphinus delphis, the Black Sea, Cetacean mortality
Abstract: The aim of the present study was to gather data on mortality of harbor porpoise (Phocoena phocoena), bottlenose dolphin (Tursiops truncatus), and common dolphin (Delphinus delphis), the three representatives of Order Cetacea in the Black Sea, using noninvasive approaches. 27 sample areas were monitored using transects 1 to 10 km long. Samplings have been done from March to October 2016. Transects were passed along two to seven times. 55 full or partial carcasses of the three Cetacean species were registered. 280 stranding cases were analyzed in total, 150 of which were identified simultaneously at species and relative age level. The prevailing species was Phocoena phocoena (49,3%). Tursiops truncatus was identified in 9,3% and Delphinus delphis – 6,1% of the cases, and 35,3% remained unidentified at species level. In general 37% of the registered corpses belong to the age class up to 1 year. This high proportion was shown to be due to the newborns of the harbor porpoise. The mortality among Ph. phocoena of age class up to 1 year was significantly higher than those of the age classes above 1 year. The most significant number of strandings was observed in July (123 cases).