Harbour Porpoise

Common Porpoise

  • Scientific name: Phocoena phocoena
  • Also know as: Common Porpoise
  • Size: Up to six feet in length and 200lbs.
  • IUCN Status
    • Global: LC (Least Concern)
    • Europe: VU (Vulnerable)
  • Distribution: Found in shallower, inshore waters throughout much of the northern hemisphere.
  • Feeds on: Mostly fish and squid.
  • Description: Small marine mammal which has a robust squat body. Snout is much shorter than that of dolphins. Triangular dorsal fin. Colour is dark grey on the back with darker fins and a white/pale underside.

The harbour porpoise is a small porpoise species which grows to around five to six feet in length, making it one of the smaller marine mammal species in the world. While porpoises are sometimes seen as a small type of dolphin they are in fact a separate species, with the main differences being that porpoises have a much shorter, blunter snout, and their teeth are flattened and square shaped, unlike the cone-shaped teeth of dolphins.

Distribution

Common Porpoise Distribution

Worldwide distribution of the harbour porpoise. Note the isolated population in the Black Sea.

The harbour porpoise is found throughout most of the colder waters of the northern hemisphere. They are found on both coasts of North America, along the coast of North Africa and throughout European waters. They are not commonly sighted in the Mediterranean, and a separate population exists in the Black Sea, which is classed as a sub-species.

Life Cycle

Harbour Porpoise Size Comparison

Size comparison between a harbour porpoise and human.

Harbour porpoises prefer shallow water and are often found around harbours, estuaries and bays (as their name suggests), making them one of the most commonly sighted cetacean species from the shore. Harbour porpoise live in small groups, although sometimes harbour porpoise will live a solitary life, joining with other porpoises only to reproduce. Like most marine mammals species the females care for the young and provide milk for the young to feed on for the first year or so of life.

Feeding

Harbour porpoises feed mostly on fish and squid species. They are unfussy and will feed on and around the seabed for demersal species such as cod, haddock and flatfish, and will also hunt pelagic fish such as herring and mackerel. There is a high level of regional variation in the diets of this species depending on the prey species which are available.

IUCN Status Conservation Issues

Common Porpoise IUCN

The harbour porpoise is classes as a species of Least Concern by the IUCN on a global basis, but Vulnerable in European waters.

Harbour porpoises were hunted commercially up until the middle of the 1900s for their oil and blubber, while their flesh was also eaten. However, harbour porpoises are no longer hunted in any significant numbers, meaning that populations have been able to stabalise in recent years, with the IUCN (International Union for the Conservation of Nature) classing the harbour porpoise as a species of Least Concern on a worldwide basis. However, the picture is not as positive in Europe, where this species is classed as Vulnerable with a declining population trend. This is because the number of harbour porpoises have reduced considerably in certain areas of Europe such as the Black Sea and the Baltic. While hunting of this species has almost completely stopped (only Greenland still catches this species in very small numbers) other issues have depleted the numbers of this species. The biggest threat is harbour porpoises being inadvertently caught in commercial fishing nets – especially gill nets – a situation made worse due to harbour porpoise live and feed in shallow, inshore waters where gill nets are more likely to be set. However, dwindling numbers of fish for harbour porpoises to eat, high levels of pollution and disturbances by busy shipping lanes and military sonar all add to the decline of the harbour porpoise in European waters.

There is some hope that European populations of harbour porpoises can recover. This species is helped by the fact that they can breed relatively early in life and give birth to young every year – many of the larger whale and dolphin species have to older before they can reproduce and also have a much longer gestation period. Furthermore, European Union legislation has recently been introduced which aims to reduce the numbers of this species which are caught as bycatch by commercial fishing vessels.

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