Seasonal dynamics of occurrence and group size of three species of cetaceans (Delphinidae and Phocoenidae) on the southwestern coast of the Black Sea




Black Sea, common dolphin, bottlenose dolphin, harbour porpoise, seasonal dynamics, time series, group size


The spatial and temporal occurrence of cetaceans in the Black Sea and particularly along its southwestern coastline is poorly studied. Based on a total of 609 encounters, we present the analysis of monthly dynamics of (1) the numbers of cetacean sightings and (2) their group size for all three Black Sea cetacean species: the bottlenose dolphin (Tursiops truncatus), the short-beaked common dolphin (Delphinus delphis) and the harbour porpoise (Phocoena phocoena) over a continuous period of 29 months (January 2018 - May 2020) from two fixed coastal observation points near the city of Zonguldak, Turkey. Seasonal fluctuations were found in the occurrence of all three species, with peaks in April-May (spring). Similarly, the largest groups of P. phocoena and T. truncatus were recorded in the late spring and early summer period, while D. delphis had a peak in July (summer). In case of the harbour porpoise, we speculate that these variations can be explained by the annual migrations from the northwestern to southern waters of the Black Sea, while the seasonal dynamics of the two Delphinidae species might depend on fish prey availability. While our data were collected locally, the results provide better insight into the ecology of cetaceans within the entire Black Sea.


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Barker J., Berrow S. 2016. Temporal and spatial variation in group size of bottlenose dolphins (Tursiops truncatus) in the Shannon Estuary, Ireland. Biol. Environ. Proc. R. Ir. Acad. 116: 63-70.

Baş A.A., Öztürk B., Amaha Öztürk A. 2019. Encounter rate, residency pattern and site fidelity of bottlenose dolphins (Tursiops truncatus) within the Istanbul Strait, Turkey. J. Mar. Biol. Ass. U.K. 99: 1009-1016.

Birkun A.A. Jr. 2006. Cetaceans. In: Zaitsev Y.P., Aleksandrov B.G., et a (eds), The North-Western Part of the Black Sea: Biology and Ecology. Naukova Dumka, Kiev, Ukraine, pp. 314- 332. (In Russian).

Birkun A. Jr., Northridge S.P., Willsteed E.A., et al. 2014. Studies for Carrying Out the Common Fisheries Policy: Adverse Fisheries Impacts on Cetacean Populations in the Black Sea. Final report to the European Commission. Brussels, Belgium, 347 pp.

Bouveroux T.N., Caputo M., Froneman P.W., et al. 2018. Largest reported groups for the Indo-Pacific bottlenose dolphin (Tursiops aduncus) found in Algoa Bay, South Africa: Trends and potential drivers. Mar. Mamm. Sci. 34: 645-665.

Black Sea Commission (BSC). 2008. State of the Environment of the Black Sea (2001-2006/7). In: Oğuz T. (ed.), Publications of the Commission on the Protection of the Black Sea Against Pollution (BSC) 2008-3. Istambul, Turkey. 448 pp.

Çelikkale M.S., Karacam H., Düzgünes E., et al. 1989. Size and distribution of dolphin populations in the Black Sea. Turkish. J. Zool. 13: 189- 196.

Clarke R.H., Gales R., Schulz M. 2017. Land-based observations of cetaceans and a review of recent strandings at subantarctic Macquarie Island. Aust. Mammal. 39: 248-253.

Conover W.J., Iman R.L. 1981. Rank transformations as a bridge between parametric and non-parametric statistics. Am. Stat. 35: 124-129.

Dede A., Tonay A.M. 2010. Cetacean Sightings in the Western Black Sea in Autumn 2007. J. Environ. Prot. Ecol. 11: 1491-1494.

Dede A., Öztürk A.A., Akamatsu T., et al. 2014. Long-term passive acoustic monitoring revealed seasonal and diel patterns of cetacean presence in the Istanbul Strait. J. Mar. Biol. Ass. U.K. 94: 1195-1202.

Elliser C.R., MacIver K.H., Green M. 2017. Group characteristics, site fidelity, and photo-identification of harbor porpoises, Phocoena phocoena, in Burrows Pass, Fidalgo Island, Washington. Mar. Mamm. Sci. 34: 365-384.

Genov T., Centrih T., Kotnjek P., et al. 2019. Behavioural and temporal partitioning of dolphin social groups in the northern Adriatic Sea. Mar. Biol. 166: 11. PMid:30613111 PMCid:PMC6299055

Gibson Q.A., Mann J. 2008. The size, composition and function of wild bottlenose dolphin (Tursiops sp.) mother-calf groups in Shark Bay, Australia. Anim. Behav. 76: 389-405.

Gladilina E.V. 2012. Observations of Cetaceans (Cetacea) in the waters of Karadag nature reserve and the adjacent waters. Scientific Notes TNU. Series "Biology, Chemistry" 25: 51-59. (In Russian).

Gladilina E.V., Gol'din P.E. 2014. New prey fishes in diet of Black Sea bottlenose dolphin (Mammalia, Cetacea). Vestn. Zool. 48: 83-92.

Gladilina E.V., Gol'din P.E. 2016. Abundance and Summer Distribution of a Local Stock of Black Sea Bottlenose dolphins, Tursiops truncatus (Cetacea, Delphinidae), in Coastal Waters near Sudak (Ukraina, Crimea). Vestn. Zool. 50: 49-56.

Gladilina E.V., Kukushkin O.V., Gol'din P.E. 2009. Current status of cetaceans in the waters of Karadag Natural Reserve. In: Gaevskaya A.V., Morozova A.L. (eds), Collection of scientific papers dedicated to the 95th anniversary of the Karadag scientific station and the 30th anniversary of Karadag Nature Reserve NAS Ukraine. ECOSY-Gidrofizika, Sevastopol, pp. 407-412.

Gladilina E.V., Lyashenko Y.N., Gol'din P.E. 2013. Winter distribution of cetaceans in the Black Sea and adjoining areas in 2012/2013. Scientific Notes TNU. Series "Biology, Chemistry" 26: 37-42.

Gol'din P., Gladilina E. 2015. Small dolphins in a small sea: age, growth and life-history aspects of the Black Sea common bottlenose dolphin Tursiops truncatus. Aquat. Biol. 23: 159-166.

Hammond P.S., Bearzi G., Bjørge A., et al. 2008. Delphinus delphis. In: IUCN 2020. IUCN Red List of Threatened Species. Version 2020.1. Downloaded on 23 May 2020.

Heithaus M.R., Dill L. 2009. Feeding strategies and tactics. In: Perrin W.F., Wursig B., et al. (eds), The encyclopedia of marine mammals, 2nd edition. Academic Press, San Diego, California, pp. 414-423.

Ivanov V.A., Belokopytov V.N. 2013. Oceanography of the Black Sea. National Academy of Science of Ukraine, Marine Hydrophysical Institute, Sevastopol, 210 pp.

Kerr K., Defran R., Campbell G. 2005. Bottlenose Dolphins (Tursiops truncatus) in the Drowned Cayes, Belize: Group Size, Site Fidelity and Abundance. Caribb. J. Sci. 41: 172-177.

Kleinenberg S.E. 1956. Mammals of the Black Sea and the Sea of Azov: an Experience of Biological and Fisheries Research. USSR Acad. Science Publ. House, Moscow, 290 pp. (In Russian).

Kopaliani N., Gurielidze Z., Devidze N., et al. 2015. Monitoring of Black Sea Cetacean in Georgian Waters. Accessed on 17 May 2020 at

Latif M.A., Özsoy E., Oğuz T., et al. 1991. Observations of the Mediterranean inflow into the Black Sea. Deep Sea Res. 38: 711-723.

Learmonth J.A., Murphy S., Luque P.L., et al. 2014. Life history of harbor porpoises (Phocoena phocoena) in Scottish (UK) waters. Mar. Mamm. Sci. 30: 1427-1455.

Marini C., Fossa F., Paoli C., et al. 2015. Predicting bottlenose dolphin distribution along Liguria coast (Northwestern Mediterranean Sea) through different modeling techniques and indirect predictors. J. Environ. Manage. 150: 9-20. PMid:25460419

Mikhalev Y.A. 2005a. The Peculiarities of the Distribution of Bottlenose Dolphin Tursiops truncatus (Cetacea) in the Black Sea. Vestn. Zool. 39: 29-42.

Mikhalev Y.A. 2005b. The Peculiarities of the Distribution of the Harbour Porpoise Phocoena phocoena relicta (Cetacea) in the Black Sea. Vestn. Zool. 39: 25-35.

Mikhalev Y.A. 2008. Results of observations on distribution of common dolphins in the Black Sea. In: Marine Mammals of the Holartic. Collection of Scientific Papers. Odessa, Ukraine, pp. 364-368.

Natoli A., Canadas A., Vaquero C., et al. 2008. Conservation genetics of the short-beaked common dolphin (Delphinus delphis) in the Mediterranean Sea and in the eastern North Atlantic Ocean. Conserv. Genet. 9: 1479-1487.

Oğuz T. 2005. Hydraulic adjustments of the Bosphorus Exchange flow. Geophys. Res. Lett. 32: L06604.

Paiu R.M., Olariu B., Paiu A.I., et al. 2019a. Cetaceans in the coastal waters of southern Romania: initial assessment of abundance, distribution, and seasonal trends. J. Black Sea/Medit. Environ. 25: 266-279.

Paiu R.M., Mirea-Candea M., Belmont J., et al. 2019b. CeNoBS - a step closer in completing a generation dream: Basin-wide survey of cetaceans in ACCOBAMS area. In: World Marine Mammals conference. Book of Abstracts. International Barcelona Convention Center, Barcelona, Spain, pp. 611-612.

Panayotova M., Todorova V. 2015a. Distribution of three cetacean species along the Bulgarian Black Sea coast in 2006-2013. J. Black Sea/Medit. Environ. 21: 45-53.

Panayotova M.D., Todorova V.R. 2015b. Using Opportunistic Sightings to Assess the Distribution of Small Cetaceans in Bulgarian Waters of the Black Sea in 2012. Acta Zool. Bulg. 67: 421-427.

Panayotova M., Marinova V., Slavova K., et al. 2017. Studying of the distribution and abundance of marine mammals in the Bulgarian Black Sea area by combination of visual and acoustic observations. Proc. Inst. Fish. Resour. 28: 34-40.

R Core Team. 2020. R: A language and environment for statistical computing. R Foundation for Statistical Computing. Vienna, Austria.

Reeves R., Notarbartolo di Sciara G. 2006. The status and distribution of cetaceans in the Black Sea and Mediterranean Sea. IUCN Centre for Mediterranean Cooperation, Malaga, Spain, 137 pp.

Rogan E., Ingram S., Holmes B., et al. 2000. A survey of bottlenose dolphins (Tursiops truncatus) in the Shannon estuary. Mar. Resour. Ser. 9: 1-46.

Ryakov V., Panayotova M. 2012. Cetacean sightings of the Bulgarian Black Sea coast over the period 2006-2010. J. Environ. Prot. Ecol. 13: 1824-1835.

Sanchez-Cabanes A., Nimak-Wood M., Harris N., et al. 2017. Habitat preferences about three top predators inhabiting a degraded ecosystem, the Black Sea. Sci. Mar. 81: 217-227.

Tenan S., Hernández N., Fearnbach H., et al. 2020. Impact of maritime traffic and whale-watching on apparent survival of bottlenose dolphins in the Strait of Gibraltar. Aquat. Conserv. 30: 949-958.

Tezcan D., Yücel M., Çiftçi G. 2017. Geology and geophysics of the southern shelf of the Black Sea. In: Sezgin M., Bat L., et al. (eds), Sea Marine Environment: The Turkish Shelf. Turkish Marine Research Foundation, İstambul, Turkey, pp. 32-51.

Tonay A., Öztürk A.A. 2012. Historical records of cetacean fishery in the Turkish seas. J. Black Sea/Medit. Environ. 18: 388-399.

Tonay A.M., Uzun B., Dede A., et al. 2020. Population genetic structure of the short-beaked common dolphin from the Black Sea and the Turkish Straits System. Mitochondrial DNA Part A 31: 257-264. PMid:32654598

Viaud-Martinez K.A., Milmer M.V., Gol'din P.E., et al. 2007. Morphological and genetic differentiation of the Black Sea harbour porpoise Phocoena phocoena. Mar. Ecol. Prog. Ser. 338: 281-294.

Viaud-Martinez K.A., Brownell R.L. Jr., Komnenouc A., et al. 2008. Genetic isolation and morphological divergence of Black Sea bottlenose dolphins. Biol. Conserv. 141: 1600-1611.

Vishnyakova K., Gol'din P. 2015. Seasonality of strandings and bycatch of harbour porpoises in the Sea of Azov: the effects of fisheries, weather conditions, and life history. ICES J. Mar. Sci. 72: 981-991.

Uluduz N., Gladilina E., Yanchukov A., et al. 2019. Primary abundance estimation of the Black Sea cetaceans in the adjacent waters of Zonguldak, Turkey. In: EEBST 2019. Ecology and Evolutionary Biology Symposium. Abstract Book. Ankara, Turkey, pp. 44.

Wittkowski K.M., Song T. 2012. MuStat: Prentice Rank Sum Test and McNemar Test. R package version 1.7.0. Downloaded on 15 May 2020.

Würsig B. 1978. Occurrence and group organization of Atlantic bottlenose porpoises (Tursiops truncatus) in an Argentine bay. Biol. Bull. 154: 348-359.

Zaitsev Y. 2008. An Introduction to the Black Sea Ecology. Smil Ed. Publ. Agency Ltd., Odessa, 228 pp.



How to Cite

Uluduz N, Yanchukov A, Sözen M. Seasonal dynamics of occurrence and group size of three species of cetaceans (Delphinidae and Phocoenidae) on the southwestern coast of the Black Sea. Sci. mar. [Internet]. 2020Dec.11 [cited 2024Mar.1];84(4):431-9. Available from: