Phocoena phocoena

Geographic Range

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 nearctic
  • native native
• palearctic palearctic
  • native native
• arctic ocean arctic ocean
  • native native
• atlantic ocean atlantic ocean
  • native native
• pacific ocean pacific ocean
  • native native
• mediterranean sea
  • native native

• Other Geographic Terms
• holarctic holarctic

Habitat

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 temperate
• polar polar
• saltwater or marine saltwater or marine
• freshwater freshwater

• Aquatic Biomes
• pelagic pelagic
• rivers and streams
• coastal coastal
• brackish water brackish water

• Other Habitat Features
• estuarine estuarine

Physical Description

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 .

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

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))

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

Lifespan/Longevity

Behavior

The species usually swims near the surface, rising to the surface to breath about every 25 seconds. It does not present a very playful attitude, ignoring boats and rarely jumping out of the water. Harbor Porpoises do not move particularly fast, but when pursued can reach speeds of around 23km/hr. When diving for food this porpoise stays down for an average of 4 minutes, and is believed to be able to dive as deep as 200m. Although schools of up to 100 individuals may sometimes be seen, P. phocoena is usually seen in pairs or in groups of 5-10. When the larger groups do occur, it is usually because a number of smaller groups have joined together while following a rich food source. Mothers bring newborn calves to secluded coves to nurse. Some populations are known to migrate, but when they return to their regular waters they are territorial, patrolling certain areas. (Johnston(1999), Nowak(1999))

• Key Behaviors
• natatorial natatorial
• motile motile
• migratory migratory
• territorial territorial
• social social

Communication and Perception

• Perception Channels
• tactile tactile
• chemical chemical

Food Habits

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))

• Primary Diet
• carnivore carnivore
  • piscivore piscivore

• Animal Foods
• fish
• mollusks
• aquatic crustaceans

Economic Importance for Humans: Positive

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.

Conservation Status

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))

Other Comments

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.

Additional Links

Encyclopedia of Life

Contributors

George Hammond (), Animal Diversity Web.

Andrew Masi (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Dollinger (editor), P. 1988. Convention on International Trade in Endangered Species of Wild Fauna and Flora; Identification Manual Vol I. Mammalia . Switzerland: Secretariat of the Convention.

Johnston, D. 2001. "Harbour Porpoise" (On-line). @Phocoena.org. Accessed 11/03/04 at http://phocoena.org/factsheets/harbourporp.html .

Nowak, R. 1999. Walker's Mammals of the World, 6th Ed. Vol II . Baltimore: John Hopkins University Press.

The Porpoise Page, 1998. "Harbor Porpoise" (On-line). The Porpoise Page. Accessed 11/03/04 at http://www.theporpoisepage.com/harbor.php .