The subspecies’ range includes the Black Sea proper, Azov Sea, Kerch Strait (e.g., Tzalkin 1938), Marmara Sea, Bosphorus Strait (Öztürk and Öztürk 1997), northern Aegean Sea (Frantzis et al. 2001) and also, very likely, the Dardanelles Straits (Harun Guclusoy 2006, pers. comm. to Frantzis) connecting the Marmara and northern Aegean Seas (see Figure 1 in attached PDF). The Black Sea population is completely isolated from the nearest P. phocoena population in the northeastern Atlantic by a wide range hiatus in the
The range of the Black Sea subspecies includes territorial waters and exclusive economic zones of Bulgaria, Georgia, Romania, Russia, Turkey and Ukraine in the Black Sea; internal waters of Ukraine in the Black Sea (including the Dnieper-and-Boug Liman and Karkinitsky Bay); internal waters of Russia and Ukraine in the Azov Sea and Kerch Strait; internal waters of Turkey (TSS, including the Bosphorus Strait, Marmara Sea and, possibly, the Dardanelles); Greek territorial waters in the northern Aegean Sea (Thracian Sea, Kavala Gulf, Strymonikos Gulf, Agiou Orous Gulf, and Thermaikos Gulf); and possibly Turkish territorial waters of the northeastern Aegean Sea, at the exit of the Dardanelles Straits. Occasionally, Harbour Porpoises have been sighted in the Danube, Dnieper, Don and Kuban rivers, their estuaries, deltas and tributaries (e.g., in the Danube in 1984-1989 and 2003 or in the Ingulets, a confluent of the Dnieper, in 1999), and coastal freshwater, brackish and saline lakes and lagoons including the Yalpug and Sivash lakes, Berezansky and Grigorievsky lagoons, Tendrovsky, Yagorlytsky and Jarylgachsky bays, and the Gulf of Taganrog (Tzalkin 1940a, Geptner et al. 1976, Birkun 2006). All of these sites are situated in
The population of P. p. relicta may consist of three or more subpopulations including those that spend much of the year in geographically and ecologically different areas, e.g. the
[Definition: Territorial waters of all six
Habitat and Ecology
Harbour Porpoises inhabit mainly shallow waters (0–200 m deep) over the continental shelf around the entire perimeter of the
Harbour Porpoises undertake annual migrations, leaving the Azov Sea (Tzalkin 1938) and northwestern
The mean group size varies from 1.4 to 7.7 in different areas (Birkun et al. 2002, 2003, 2004; Krivokhizhin et al. 2006) although during their seasonal migration, animals may remain for a few days at different sites (usually bays with abundant fish) forming dense aggregations of some hundreds of individuals, e.g. off the southern coast of Crimea in December-January 1994 (Laspi Bay), March 1995 (near Cape Meganom) and April 2005 (between Cape Aya and Cape Fiolent) (Birkun and Krivokhizhin unpublished data). Sometimes, early and rapid ice formation, arising immediately after an “Indian summer”, can prevent animals leaving the
The ecology of
IUCN Red List Assessment
Red List Category
Red List Criteria
The estimated generation time is 8-12 years (depending on population status), thus three generations for the Black Sea Harbour Porpoises (using the natural, or pre-disturbance, value of 12) would be 36 years, or 1972-2007.
There are no estimates of unexploited or present total population size, although the available information suggests that present population size is at least several thousands and possibly in the low tens of thousands.
The following information from the last three decades is relevant to the proposed classification. However, it is important to note that very high levels of direct and incidental mortality occurred for a long period before then (from the 1830s and throughout the 20th century) and this undoubtedly would have dramatically reduced the population prior to the 1970s (IWC 2004).
(1) Large directed takes occurred during the years 1976-1983 before the ban on small cetacean hunting was declared in
(2) Regionally extensive incidental mortality of porpoises in bottom-set gillnets is roughly estimated to have been in the thousands annually through the 1980s. The scale of this mortality almost certainly increased in the 1990s-2000s owing to the rapid expansion of illegal, unreported and unregulated fishing in the
(3) A major mass mortality event occurred in the
(4) Two other mass mortality events occurred in 1989 and 1990, attributed to the combined effects of parasitic and bacterial infections. Although difficult to quantify, the mortality of porpoises is believed to have been in the thousands.
(5) Periodically (most recently in November 1993), natural mass mortality events occur as a result of ice entrapment in the
(6) There has been general and ongoing degradation of the
EN: A1d. A reduction in population size of 70% over the past 30 years (see note at end of paragraph) is inferred based on paragraphs (1) and (3) above, i.e. the directed takes and, to a lesser degree, the accident in 1982 (considered ‘actual exploitation’ in the context of IUCN Red List Criteria). These causes were clearly reversible and understood and they have ceased. Despite the absence of abundance estimates for the initial part of the 30-year period, the suspected decline of 70% is based on inferences from a crude extrapolation based on the annual removal levels in the Turkish fishery: a reduction of 70% implies that the population in 1976 must have been at least 233,000-302,000, whereas a reduction of 50% (threshold for Vulnerable) would require a population size of at least 326,000-422,000. The latter seems unrealistic given the duration and intensity of past exploitation. [Note: The numerical analyses were conducted at the
EN: A4cde. A reduction in population size of >50% over a 30-year period that includes both the past and the future is inferred based on the above paragraphs except (1) and (3). During this period, although direct killing has ceased, the other known or suspected causes of decline (bycatch, habitat degradation, prey depletion, epizootics and adverse climatic circumstances) have not ceased.
Total population size is unknown and therefore a synoptic region-wide survey is essential. Past Black Sea region-wide estimates based on strip transect surveys carried out in the
Line transect surveys have been conducted recently to estimate Harbour Porpoise abundance in different parts of the range. In particular, aerial surveys were conducted in the Azov Sea, Kerch Strait (2001, 2002) and northeastern shelf area of the Black Sea (2002); vessel-based surveys were performed in the Kerch Strait, the entire 12-mile-wide zone of the Ukrainian and Russian Black Sea (2003), Georgian territorial sea (2005), and central part of the Black Sea between the Crimea peninsula, Ukraine, and Sinop province of Turkey (September–October 2005). Results of those surveys (see Table 1 in the attached PDF, see link below) suggest that present total population size is at least several thousands and possibly in the low tens of thousands.
In the 20th century, the number of Black Sea Harbour Porpoises was dramatically reduced by massive direct killing for the cetacean-processing industry that continued until 1983 (e.g. Smith 1982, IWC 2004). The numbers of animals taken were not recorded accurately; much of the catch data was recorded as numbers of animals undifferentiated to species (all three
Until 1983, unregulated hunting was the primary threat (IWC 1992, 2004). Very large numbers of harbour porpoises, as well as other cetaceans, were taken during the 20th century by all
At present, incidental mortality in fishing nets is the most serious threat (e.g., Birkun 2002a). Although all three
An explosion at a gas-drilling platform in the
Large-scale pelagic and small-scale coastal fisheries may affect
Black Sea Harbour Porpoises are also affected in some years by ice entrapment in the
Commercial hunting of Black Sea cetaceans, including Harbour Porpoises, was banned in 1966 in the former
On a national level,