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One interesting danger that the Harbor Porpoise may be facing is completely natural. As one group of researchers noticed, a number of porpoise carcasses taken in Scotland all had similar puncture and bruise wounds, with most of them dying as a result of internal injury. In addition to these injuries some of the specimens also had teeth gouges in their flesh. After analyzing these bite patterns, the researchers determined that the animal responsible for inflicting these wounds was Tursiops truncatus, the Bottlenosed Dolphin. At least in this area of Scotland it seems that where the two species' ranges overlap, dolphins are attacking and in some cases killing porpoises. It is not known for sure exactly what is prompting this kind of behavior.

Perception Channels: tactile ; chemical

Although fishing of P. phocoena is now illegal in most areas, the species is still in danger. Deliberate and accidental deaths still occur because modern fishing nets are almost undetectable to porpoises. Since these nets are commonly used in nearshore areas, in the natural range of P. phocoena, they probably kill large numbers of porpoises. Various measures are being taken in the United States and other nations in an attempt to limit deaths of this kind. In addition to deaths related to fishing, porpoises also suffer from chemical and noise pollution. (Dollinger(1988), Johnston(1999), McWilliam(1999), Nowak(1999))

CITES: appendix ii

IUCN Red List of Threatened Species: critically endangered

Taken heavily in various areas, the meat is used for human and animal consumption, and its oil is used in lamps and as a lubricant.

Diet consists mainly of smooth, non-spiny fish, and cephalopods. Herring, pollack, hake, sardines, and cod are commonly eaten. Other sea creatures such as squid and shrimp are also consumed. P. phocoena produces click-like sounds similar to those used by other cetaceans as a means of echolocation in order to locate food.(Johnston(1999), Nowak(1999))

Animal Foods: fish; mollusks; aquatic crustaceans

Primary Diet: carnivore (Piscivore )

Found in coastal regions of the North Atlantic, Arctic, and North Pacific Oceans; also the Mediterranean and Black Sea regions. They are found in bays, estuaries, river mouths, and sometimes ascend further up rivers.

Biogeographic Regions: nearctic (Native ); palearctic (Native ); arctic ocean (Native ); atlantic ocean (Native ); pacific ocean (Native ); mediterranean sea (Native )

Other Geographic Terms: holarctic

Found in both salt and fresh water areas, Phocoena phocoena require a shallow coastal body of water. In the Western Atlantic, they also move far out to sea near the end of summer and reappear in spring. Other regional populations move south or farther away from shore to avoid ice buildups.

Habitat Regions: temperate ; polar ; saltwater or marine ; freshwater

Aquatic Biomes: pelagic ; rivers and streams; coastal ; brackish water

Other Habitat Features: estuarine

Average lifespan
Status: wild: 13.0 years.

Phocoena phocoena, also known as the "Common" or "Harbor" Porpoise, is a small cetacean that is 1.5 to 2 meters long and weighs from 45 - 65 kilograms. The female of the species is usually slightly larger than the male. The color of the animal varies from individual to individual, but the most common coloration pattern is a dark dorsal surface that shifts to a lighter colored hue ventrally. Although the dark color is usually black or deep gray, albinos have been reported in which the dark segments are completely or partially white. The flippers, dorsal fin, and tail are all dark in color, and there is a black stripe that runs from the edge of the mouth or eye to the flipper on either side. There is no noticeable forehead or beak on this species, and the snout is short, giving the head a somewhat cone-like shape. P. phocoena has two pectoral flippers, a single dorsal fin, and a tail with two partially separated flukes. All of these appendages are short and not very sharp, with the dorsal fin being triangular shaped and usually around 15 - 20 cm tall. There is a noticeable keel located near the all dark tail flukes, with the tail itself spanning anywhere from 30-65 cm. Inside the slightly upturned mouth there are rows of 16-28 spade-shaped teeth. There is no variance in the shape or type of teeth in P. phocoena.

Range mass: 45 to 60 kg.

Range length: 1.5 to 2 m.

Sexual Dimorphism: female larger

Other Physical Features: endothermic ; bilateral symmetry

Average basal metabolic rate: 107.675 W.

It is not clearly known how extensive the mating season is in P. phocoena, but it seems that mating mainly occurs from June to September with births occurring from May to August. It is commonly noted that gestation lasts 11 months with nursing following for another 7 or 8 months. A female will give birth to one calf per year, with the birth size of the calf being 6-8kg and 70-100cm long. Sexual maturity is reached by the fifth year, if not before, and the life span of P. phocoena is believed to be anywhere from 6 to 20 years. (Johnston(1999), Nowak(1999))

Breeding interval: A female will give birth to one calf per year

Breeding season: Mating mainly occurs from June to September

Average number of offspring: 1.

Average gestation period: 11 months.

Range weaning age: 7 to 8 months.

Range age at sexual or reproductive maturity (female): 5 (high) years.

Range age at sexual or reproductive maturity (male): 5 (high) years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous

Average birth mass: 7000 g.

Average gestation period: 320 days.

Average number of offspring: 1.