The Harbour Porpoise is the most commonly seen porpoise (1).
P. phocoena is a small, stocky cetacean, with females only reaching 160cm, and males 145cm (2). Its snout lacks the prominent beak, characteristic of dolphins (3). The dorsal fin is triangular, short and wide-based, the pectoral fins are small and rounded (4); the fluke is also small with the tips rounded and divided by a prominent median notch (4).
The harbour porpoise is dark grey on the dorsal side, fading to white on the belly. The fins are also dark grey. P. phocoena has a characteristic dark stripe from the corners of its mouth to the pectoral fins (2; 4).
Harbour porpoises are notoriously shy, rarely approaching boats to bow-ride (3; 4; 2). They do not show much of themselves above the water while swimming, so sightings are brief (2). They can be spotted on calm, quiet days by their blow, which is a distinctive short puffing sound (3). Breaches and any other form of aerial behaviour are rarely seen (4).
Harbour porpoises usually reach sexual maturity at around 130cm (females) and 140cm (males) (5). The gestation period for this species is 10 to 11 months (3; 5; 6); calves are born from spring to mid-summer (4) and are 70cm in length (5). Calves are usually suckled for up to 8 months (3; 6). P. phocoena has the shortest life span out of all cetacean species, usually not living longer than 12 years (1).
Typically inhabits shallow coastal waters (3).
P. phocoena occurs in the northern Atlantic and Pacific Oceans and contiguous Seas, apart from Arctic regions (7).
The Harbour porpoise feeds mainly on cephalopods and fish (8) and its specific diet varies according to region and season (9). Their most common prey in many areas is herring and mackerel (4). P. phocoena can dive up to 220m in order to find food (10).
IUCN Red List: Least Concern (11).
Listed under Appendix II of CMS (12).
Listed under Appendix II of BERN Convention(13).
Description written by Sarah Marjoram (2009)
(1) Carwadine, M..E.H.R.E.F.a.P.G., 1998. Whales and dolphins, the ultimate guide to marine mammals. London: Harper Collins Publishers.
(2) Culik, B., 2003. Phocoena phocoena (Linnaeus 1758). [Online] Available at: http://www.cms.int/reports/small_cetaceans/data/P_phocoena/p_phocoena.htm [Accessed 29 July 2009].
(3) Society, A.C., 2006. American Cetacean Society Fact Sheet – Harbour Porpoise Phocoena phocoena. [Online] Available at: http://www.acsonline.org/factpack/HarborPorpoise.htm [Accessed 29 July 2009].
(4) FAO, 2009. Species Fact Sheets Phocoean phocoena (Linnaeus 1758). [Online] Available at: http://www.fao.org/fishery/species/2740/en [Accessed 29 July 2009].
(5) Boyd, I.L..C.L.a.H.D.M., 1999. Reproduction in Marine Mammals. In Reynolds III, J.E.a.S.A.R. Biology of Marine Mammals. Washington and London: Smithsonian Institution Press.
(6) ARKive, 2009. Species Information: Harbour Porpoise (Phocoena phocoena). [Online] Available at: http://www.arkive.org/harbour-porpoise/phocoena-phocoena/info.html [Accessed 29 July 2009].
(7) Hammond, P.S..G.B.A.B.K.F.L.K.T.K.W.F.P.M.D.S.J.Y.W.R.S.W.a.B.W., 2008. Phocoena phocoena. [Online] (2009.1) Available at: www.iucnredlist.org [Accessed 29 July 2009].
(8) Sekiguchi, K., 1995. Occurrence, behaviour and feeding habits of harbour porpoises (Phocoena phocoena) at Pajaro Dunes, Monterey Bay, California. Aquatic Mammals, 21(2), pp.91-103.
(9) Jefferson, T.A..S.L.a.M.A.W., 1993. FAO Species Identification Guide. Marine Mammals of the World. Rome: UNEP.FAO.
(10) Bjorge, A.a.K.A.T., 2002. Harbour Porpoise – Phocoena phocoena. In Perrin, W.F..B.W.J.G.M.T. Encyclopedia of Marine Mammals. San Diego: Academic Press. pp.549-52.
(11) IUCN, 2009. IUCN Red List of Threatened Species. Version 2009.1. [Online] Available at: www.iucnredlist.org [Accessed 28 July 2009].
(12) (CMS), C.o.t.C.o.M.S.o.W.A., Effective 5th March 2009. Appendices II of the Convention on the Conservation of Migratory Species of Wild Animals.
(13) Europe, C.o., 2002. Convention on the conservation of European wildlife and natural habitats: Bern Convention. [Online] Available at: http://conventions.coe.int/Treaty/FR/Treaties/Html/104-2.htm [Accessed 23 July 2009].