Scientific name: Phocoena phocoena
The harbour porpoise (Phocoena phocoena) is one of six species of porpoise and is considered one of the smallest marine mammals. In fact, the harbour porpoise is only about 67–85 cm long at birth, weighing 6.4–10 kg, with adults of both sexes growing to 1.4 to 1.9 m.
It has a rounded head which slopes down to the mouth, a flat forehead and no prominent beak (unlike the common and bottlenose dolphin). It has black lips and chin, a mouth that curves upwards as if smiling and a robust dark body, with a white or pale grey belly.
The harbour porpoise has a triangular dorsal fin with a blunt tip which is positioned just past the centre of the back. Though the dark dorsal fin is small it can appear large when scaled to the relatively small portion of visible back. It has slightly rounded flippers. Young harbour porpoises are dull in colour compared to their parents.
The harbour porpoise typically keeps a low profile in the water, but its small size, characteristic rolling swimming style and small triangular dorsal fin make it reasonably easy to recognise if the observer is able to get a good look at it. Fish, especially small schooling fish, and cephalopods, are the main prey items. They use echolocation clicks when exploring the surrounding environment. They usually swim slowly and alone or in small groups and can dive for as long as six minutes. The most common social group is that of mother and calf.
It is also referred to a puffer or puffing pig by fishermen in New England and eastern Canada. This is probably because it can at times be detected by the blow, which although rarely seen, makes a sharp puffing sound rather like a sneeze. The harbour porpoise species is widespread in cooler coastal waters of the North Atlantic, North Pacific and they occasionally travel over deeper offshore waters. In the Atlantic, harbour porpoises may be present in a curved band of water running from the coast of West Africa to the coasts of Spain, France, the United Kingdom, Ireland and Scandinavia, Iceland, Greenland, Nova Scotia and Newfoundland and the eastern seaboard of the United States.
The harbour porpoise is considered to be regular albeit rare in the Contiguous Atlantic with individuals known to occasionally stray into the Mediterranean. The past regular presence of this species in the Mediterranean is subject of controversy and in fact many argue that it was absent in historical times but one museum specimen exists which was alleged to have been captured from the Adriatic Sea. In fact, the known occurrences are from the following years and places:
• 1822, Adriatic Sea, Cagnolaro citing Alessandrini;
• 1981, Playa de Malagueta, Spain, Frantzis et al., 2001 citing Rey & Cendrero 1982, a stranded female;
• 2006, Malaga, Spain, Male, 1.65 m, stranded alive, Ana Cañadas.
The Harbour porpoise is protected by various international treaties and agreements as well as national laws including the following:
• The European Union’s (EU’s) Habitats Directive and included in Appendix II and IV;
• Endangered Species Act (ESA) Candidate Species – Baltic Sea population;
• Marine Mammal Protection Act (MMPA) – Harbour porpoises, like all marine mammals, are protected under the MMPA;
• Convention on International Trade in Endangered Species (CITES) Appendix II;
• Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS/Bonn Convention);
• Annex II of the Protocol concerning Specially Protected Areas and Biological Diversity in the Mediterranean of the Barcelona Convention
• IUCN Listing: Least Concern (LC), Baltic Sea subpopulation listed as critically endangered (CR).
The main threat to porpoises is static fishing techniques such as gill and tangle nets. By-catch in bottom-set gill nets is considered the main anthropogenic mortality factor for harbour porpoises worldwide.
Harbour porpoises were traditionally hunted for food, as well as for their blubber, which was used for lighting fuel. The drive hunt in the Little Belt strait, Denmark, is the best known example. Thousands of porpoises were caught there until the end of the 19th century, and again in smaller scale during the world wars. In the Gulf of Maine region in the early 1990s, for example, as many as 3,000 were annually drowned in commercial fishing gear like gill nets. Populations are also harmed by chemical and noise pollution. Mortality resulting from trawling by catch seems to be less of an issue, probably because porpoises are not inclined to feed inside trawls, as dolphins are known to do.