|Scientific Name:||Phocoena phocoena|
|Species Authority:||(Linnaeus, 1758)|
|Infra-specific Taxa Assessed:|
Phocoena relicta Abel, 1905.
|Taxonomic Notes:||Four subspecies are recognized: P. p. phocoena in the North Atlantic, P. p. vomerina, in the eastern North Pacific, an un-named subspecies in the western North Pacific (Rice 1998) and P. p. relicta in the Black Sea (Reeves and Notarbartolo di Sciara 2006).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Hammond, P.S., Bearzi, G., Bjørge, A., Forney, K., Karczmarski, L., Kasuya, T., Perrin, W.F., Scott, M.D., Wang, J.Y., Wells, R.S. & Wilson, B.|
|Reviewer/s:||Rojas-Bracho, L. & Smith, B.D. (Cetacean Red List Authority)|
Although the species is known to be harvested in two areas and regional declines are described, it is widespread and abundant. In some of the major habitats for harbour porpoises (the shelf waters of the USA and Europe) conservation measures are implemented.
|Range Description:||Harbour porpoises are found in cold temperate to sub-polar waters of the Northern Hemisphere (Gaskin 1992, Read 1999). They are usually found in continental shelf waters, although they occasionally travel over deeper offshore waters. In the North Pacific, they range from central California and northern Honshu to the southern Beaufort and Chukchi Seas (including the Bering and Okhotsk Seas, and Sea of Japan). In the North Atlantic, they are found from the southeastern United States to southern Baffin Island (they apparently do not enter Hudson Bay) in the west, and from Senegal to Novaya Zemlya in the east. They also occur around southeast and western Greenland, Iceland, and the Faroe Islands, and this is the only cetacean species that currently regularly occupies the Baltic Sea. The species occurs in the Black Sea, Marmara Sea, and Sea of Azov, but with the exception of the adjacent northern Aegean Sea, they do not regularly occur in the Mediterranean Sea.|
Native:Belgium; Bulgaria; Canada; Cape Verde; China; Denmark; Estonia; Faroe Islands; Finland; France; Georgia; Germany; Gibraltar; Greenland; Iceland; Ireland; Japan; Latvia; Lithuania; Mauritania; Morocco; Netherlands; Norway; Poland; Portugal; Romania; Russian Federation; Senegal; Spain; Sweden; Tunisia; Turkey; Ukraine; United Kingdom; United States (Georgia); Western Sahara
|FAO Marine Fishing Areas:||
Arctic Sea; Atlantic – eastern central; Atlantic – northeast; Atlantic – northwest; Mediterranean and Black Sea; Pacific – eastern central; Pacific – northeast; Pacific – northwest
|Range Map:||Click here to open the map viewer and explore range.|
In the North Atlantic Ocean (including the Black and Azov seas), fourteen population units have been proposed (Donovan and Bjørge 1995), and in the North Pacific, several population units have been identified based on genetic studies (Chivers et al. 2002).
There are no synoptic surveys covering the entire range within ocean basins, but abundance has been estimated for selected portions of the range. Abundance estimates have been summarized by Read 1999 (but see updates in Angliss and Outlaw 2005, Carretta et al. 2006, Waring et al. 2006). About 73,000 animals have been estimated to occur along the west coast of the USA (including 1,656 [CV=0.39] in the Morro Bay population, 1,613 [CV=0.42] in the Monterey Bay population, 8,521 [CV=0.38] from San Francisco to the Russian River, 17,763 [CV=0.39] in northern California and southern Oregon, 39,586 [CV=0.38] in Oregon and Washington, and 3,509 [CV=0.40] in Washington inland waters). In Alaska abundance is estimated at about 89,000 (including 10,947 [CV=0.24] in southeast Alaska, 30,506 [CV=0.21] in the Gulf of Alaska, and 47,356 [CV=0.22] in the Bering Sea) (see summary in Angliss and Outlaw 2005). In the western Atlantic, there are an estimated 75,438 [CV=0.42] in the Gulf of Maine/Upper Bay of Fundy to the entrance of the Gulf of St. Lawrence, and 27,000 for the Gulf of St. Lawrence (Waring et al. 2007). Abundance has been estimated at 27,000 in Iceland (Stenson 2003) and 11,000 [CV=0.44] off North Norway - Barents Sea (Bjørge and Øien 1995). In the waters of the European Atlantic, abundance in 2005 was estimated at 385,600 [CV=0.20] (P.S. Hammond pers. comm.), of which about 335,000 [CV=0.21] were estimated in the North Sea and adjacent waters, where abundance was estimated at 341,000 [CV=0.14] in 1994 (Hammond et al. 2002). The abundance in the Baltic Sea is estimated at 599 (CV = 0.57) (Hiby and Lovell 1996). Line transect surveys have been conducted recently (since 2001) to estimate harbour porpoise abundance in different portions of the Black Sea. These suggest that total population size in the region may be at least several thousand and perhaps as much as 10,000-12,000 (Reeves and Notarbartolo di Sciara 2006).
Taken together, these numbers indicate that the global abundance of the harbour porpoise is at least about 700,000 individuals.
There is evidence of decline in abundance in some areas, e.g. in the Black Sea (Reeves and Notarbartolo di Sciara 2006), in the Baltic Sea (see account for that subpopulation), and in inland waterways of Washington State, USA (Osmek et al. 1996).
|Habitat and Ecology:||
Throughout its range, P. phocoena is largely limited to continental shelf waters. They frequent relatively shallow bays, estuaries, and tidal channels less than about 200 m in depth. Carretta et al. (2001) found that the main distribution of porpoises in northern California was in waters of less than 60 m. Dives to at least 220 m have been recorded via telemetry (Bjørge and Tolley 2002, Otani et al. 1998).
Harbour porpoises eat a wide variety of fish and cephalopods, and the main prey items vary regionally (see Smith and Gaskin 1974; Recchia and Read 1989, Fontaine et al. 1994, Gonzales et al. 1994, Aarefjord et al. 1995, Gannon et al. 1998, Read, 1999, Børjesson et al. 2003, Santos et al. 2004, Reeves and Notarbartolo di Sciara 2006). Although small schooling fish (e.g. herring) are important, demersal foraging is characteristic in many areas.
The ecology of Black Sea harbour porpoises may be unusual reflecting the high degree of geographic isolation of their habitat. Low water salinity, seasonal fluctuations of water temperatures and large amounts of anoxic waters below 100-250 m (Reeves and Notarbartolo di Sciara 2006).
Surveys in 1994 and 2005 in the North Sea and adjacent waters have shown a major shift in distribution from northern to southern areas (Hammond et al. 2002, Hammond pers. comm.), a change that is reflect by increased in shore-based sightings (Camphuysen 2004, Thomsen et al. 2006).
The harbour porpoise has been hunted in many areas of its range, e.g. in Puget Sound, the Bay of Fundy, Gulf of St. Lawrence, Labrador, Newfoundland, Greenland, Iceland, Black Sea, and the Danish Belt Seas. Many of these fisheries are now closed, but hunting of harbour porpoises still occurs in Greenland. In Greenland more than 700 per year were taken in 1990-1993 (Teilmann and Dietz 1995). In 2003 the reported catch had increased to 2,320 (NAMMCO 2005). Assessments of population impacts of these takes are not available.
In the Black Sea, large directed takes occurred during 1976-1983. Within that period, the total number of harbour porpoises killed was at least 163,000-211,000. Commercial hunting of Black Sea cetaceans, including harbour porpoises, was banned in 1966 in the former USSR (present Georgia, Russia and Ukraine), Bulgaria and Romania, and in 1983 in Turkey. Illegal direct killing of unknown numbers continued in some parts of the Black Sea until 1991 (Reeves and Notarbartolo di Sciara 2006).
Today, the most significant threat in most areas is incidental catches in fishing gear, primarily gill nets. Incidental mortality in fishing gear is likely to occur throughout the range of the species, but substantial incidental takes have been documented (summarized in Donovan and Bjørge 1995) for the Gulf of Maine (1,200-2,900/year), Bay of Fundy (80-400/year), West Greenland (1,400/year), North Sea (4,600/year) Celtic Shelf (1,500/year), and also off central California during the 1980s and 1990s (tens to hundreds per year; Barlow and Hanan 1995). More recent monitoring programs of Danish set-net fisheries in the North Sea revealed an average of 5,591 porpoises taken annually in the period 1987-2001 (Vinther and Larsen 2002). However, most North Sea gillnet fisheries were not monitored for marine mammal bycatch (ICES 2002).
In the Black Sea incidental mortality in bottom-set gillnets is estimated to have been in the thousands annually through the 1980s (e.g., Birkun 2002a). Almost all (99%) of the porpoises are caught in bottom-set gillnets. The scale of this mortality almost certainly increased in recent times owing to the rapid expansion of illegal, unreported and unregulated fishing in the Black Sea.
Other types of threats include chemical pollution, vessel traffic, noise, and depletion of prey by overfishing. Due to its near shore distribution, harbour porpoises are exposed to coastal sources of pollution throughout most of its range. Chemical pollution (PCBs) has been described as having adverse effects (see Baltic subpopulation account).
An explosion at a gas-drilling platform in the Azov Sea in August 1982 resulted in the deaths of over 2,000 porpoises (Birkun 2002b).
Severe habitat degradation and prey depletion caused by intensive fishing in the Black Sea, together with explosive growth of populations of invasive species are considered important threats for local harbour porpoises (Reeves and Notarbartolo di Sciara 2006). Reduced prey availability coincided with two mass mortality events (in 1989 and 1990) that affected all three Black Sea cetacean species, but primarily harbour porpoises (Birkun 2002c). Severe pulmonary nematodosis, caused by Halocercus spp. and complicated by bacterial super-infection, was recognized as a primary cause of the deaths, which were mainly of young animals.
The species is listed in Appendix II of CITES.
In the North Sea incidental takes have been determined to be above the advised maximum level of removals. The European Union adopted a regulation aimed at reducing the incidental catch of small cetaceans in fisheries in European Union waters. The regulation includes measures restricting Baltic Sea drift net fisheries, providing for mandatory use of acoustic deterrent devices (pingers) in some EU gillnet fisheries in the North and Baltic Seas, and the use of onboard observers on vessels of over 15 m in length. A review of the progress of implementing resolution is scheduled for 2007.
|Citation:||Hammond, P.S., Bearzi, G., Bjørge, A., Forney, K., Karczmarski, L., Kasuya, T., Perrin, W.F., Scott, M.D., Wang, J.Y., Wells, R.S. & Wilson, B. 2008. Phocoena phocoena. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 19 April 2014.|