Phocoena phocoena Linnaeus, 1758

Phocoena phocoena relicta image

Synonyms: Phocoena relicta Abel, 1905; Phocoena phocoena relicta Abel, 1905

Common names: Engl: Harbour porpoise; Bulg: Mutkur, Morska svinya; Rom: Marsuin, Focena, Porc de mare; Russ: Morskaya svinya chernomorskaya, Azovka; Turk: Mutur; Ukr: Azovka, Pykhtun

Order: CETACEA

Family: PHOCOENIDAE

Taxonomic descriptions: It is a single representative of the genus and family in the Black Sea fauna. In Bulgaria, Georgia, Russian Federation and Ukraine the Black Sea harbour porpoise is known as a tight-area relic sub-species Ph. phocoena relicta. Nevertheless, to date there are no comparative genetic and/or morphometric data, which could be reliable criteria for this animal's recognition as a distinct sub-species. Most zoologists of the former USSR do not acknowledge the existence of the family Phocoenidae, and continue to list Ph. phocoena among Delphinidae. External distinctions: blunt, short-beaked head; slightly falcate, wide-based, short dorsal fin; small, spatulate, blunt teeth.

Phocoena phocoena relicta arealIUCN Status:
World level: DD
Black Sea Regional level: DD
Subregion level: EN in Ukraine and Romania, VU in Bulgaria

Distribution:

Habitats type, Critical habitats, Limiting factors: Coastal, relatively shallow waters along the perimeter of the Black Sea represent the typical circumlittoral zone of the harbour porpoise distribution. Animals do not avoid waters with low salinity and transparency; sometimes they can be observed in semifresh bays, lagoons, estuaries and even in big rivers (e.g., Danube and Don) far from the sea. Every spring significant numbers of porpoises move through the Kerch Strait to the Sea of Azov and return by the winter. The migrations through Bosphorus to the Sea of Marmora and back are very possible. Perhaps, both small seas should be recognised as the most important breeding, calving and feeding areas for the Black Sea population completely isolated from the nearest one in the North-East Atlantic. On the other hand, the Azov and Marmora Seas and their straits look like obvious critical habitats because of the heavy boat traffic, extensive fisheries and prominent water pollution there. Severe, but not so frequent, natural phenomena limiting the Black Sea population are as follows: (a) mass mortality due to lung worm infection (nematodes Halocercus taurica and H. ponticus); and (b) die-offs as a result of sudden ice formation in the Sea of Azov before animals have time to immigrate into the Black Sea.

Biology: It is a relatively short-lived marine mammal with the highest individual reproductivity in comparison with other Black Sea cetaceans. Both males and females attain sexual maturity probably at 3-4 years. Mating takes place in summer mainly, and fertilizing females become pregnant almost annually with a gestation period of 9-11 months and usually the birth of one calf per mother from May to early August. After lactation feeding (4-6 months) the youngs start their basic diet including small benthic (various goby species) and mass pelagic (anchovy, atherine) fishes inshore. The daily ration of an adult animal - 3-5 kg. The life span of Black Sea Ph. phocoena is not quite clear, perhaps it is similar to the life span of their relatives in the North Atlantic - about 7-8, maximum 15 years. Ph. phocoena is the smallest cetacean species in the Black Sea: its average body length - 1.3 to 1.5 m, maximum - 1.8 m; average weight - approximately 30 kg. The females are slightly larger than males.

Population trends: The population was strongly affected in 1930s-early 1980s by mass commercial killing. Subsequent estimates of Black Sea Ph. phocoena abundance made by Soviet and Turkish scientists (1967-1989) were defined by IWC Scientific Committee as unreliable because of unperfect methodology used for observations and extrapolations. So, at present both the animal numbers and population trends are absolutely unknown. According to recent sightings off the Bulgarian, Georgian, Romanian, and Ukrainian (Crimea) coasts, single animals and their small groups (2-10 individuals) are quite common, but herds of dozens or hudreds porpoises are rare.

Threats: Incidental killing in fishing gear, predominantly in bottom-set gill nets for turbot, dog-fish and sturgeon; technical intrusion in the sea (growth of marine traffic, gas and oil output, military manoeuvres, etc.) as a cause of disturbance, traumatism and die-offs (e.g., the mass mortality as a result of the gas-platform explosion in the Azov Sea in 1982); illegal hunting; probably, water pollution and a decline of food resources.

Conservation measures taken: The species has been included in the national Red Data Books of Bulgaria and Ukraine, and in the IUCN Red Data Book. It is protected by the Berne Convention (Appendix II), Bonn Convention (Appendix II), CITES (Appendix II), and ACCOBAMS. The state of Ph. phocoena populations is a topic for periodical review by IWC, ICES, and the Marine mammal working party of GEF/BSEP. The moratorium on Black Sea cetaceans fishing was declared in the ex-USSR countries, Bulgaria and Romania in 1966, and in Turkey in 1983.

Conservation measures proposed: Adoption of ACCOBAMS by all Black Sea countries; creation of a regional programme for marine mammal populations research and conservation including, in particular, investigations on Ph. phocoena abundance and the establishment of specially protected areas.

References:

  1. Tzalkin, V.I., 1940. Materialy k biologii morskoy svin'i (Phocaena phocaena relicta Abel) Azovskogo i Chernogo morey. (The data on biology of Azov and Black Sea harbour porpoise (Phocaena phocaena relicta Abel). Zoologichesky Zhurnal, Moscow, 19, N1, p. 160-171, (in Russian).
  2. Kleinenberg, S.E., 1956. Mlekopitayushchiye Chernogo i Azovskogo morey: opyt biologo-promyslovogo issledovaniya. (Mammals of the Black and Azov Seas: the research experience for biology and hunting). Moscow: USSR Acad. Science Publ. House, 288 pp., (in Russian).
  3. Tomilin, A.G., 1957. Zveri SSSR i prilezhashchikh stran. Tom IV. Kitoobraznyye. (Mammals of the USSR and Adjacent Countries. Vol. IV. Cetaceans). Moscow: USSR Acad. Science Publ. House, 717 pp., (in Russian).
  4. Geptner, V.G., Chapsky, K.K., Arsenyev, V.A., and Sokolov, V.E., 1976. Mlekopitayushchiye Sovetskogo Soyuza. Tom 2. Chast' 3. Lastonogiye i zubatye kity. (Mammals of the Soviet Union. Vol.2. Part 3. Pinnipeds and Toothed Whales). Moscow: Vysshaya Shkola, 718 pp., (in Russian).
  5. Arsenyev, V.A., 1980. Atlas morskikh mlekopitayushchikh SSSR. (Atlas of Marine Mammals of the USSR). Moscow: Pishchevaya Promyshlennost, 183 pp., (in Russian).
  6. Vasiliu, F., Dima, L., 1990. Some considerations regarding the presence and the mortality of the dolphins at the Black Sea Romanian littoral. In: Cercetari Marine (Marine Research), v.23. - Constantsa, p.171-176, (In French).
  7. Klinowska, M., 1991. Dolphins, Porpoises and Whales of the World. The IUCN Red Data Book. Gland and Cambridge: IUCN, viii + 429 pp., (in English).
  8. Birkun, Jr., A.A., Krivokhizhin, S.V., Shvatsky, A.B., et al., 1992. Present status and future of Black Sea dolphins. In: European research on cetaceans - 6 (Ed. by P.G.H. Evans): Proc. 6th Annual Conf. Europ. Cetacean Soc., San Remo, Italy, 20-22 February 1992. - Cambridge: ECS, p. 47-53, (in English).
  9. Birkun, Jr., A.A., and Krivokhizhin, S.V., 1996. Sovremennoye sostoyaniye i prichiny ugneteniya populyatziy chernomorskikh del'finov. Soobshcheniye 1 i 2. (Contemporary life conditions of Black Sea cetacean populations and the causes of their suppression. Parts 1 and 2). Vestnik Zoologii, Kiev, N3, p. 36-42, and N4-5, p. 53-59, (in Russian).
  10. ztrk, B., and ztrk, A.A., 1997. Preliminary study on dolphin occurrence in Turkish straits system. In: European research on cetaceans - 11 (Ed. by P.G.H. Evans): Proc. 11th Annual Conf. Europ. Cetacean Soc., Stralsund, Germany, 10-12 March 1997. - Kiel: ECS, p.79-82, (in English).
  11. Stanev, Ts.T., 1997. Distribution and number of dolphins in the Bulgarian sector of the Black Sea. In: Proc. of the Inst. Fish., v. 24. - Varna, (in Bulgarian) (In press).

Compiled by: A.Birkun, Jr., M.Moldoveanu, M.Stanciu, T.Stanev, B.ztrk