Harbour porpoise
Phocoena phocoena
likebirds214 · Quartermaster Harbor
Key facts in one look
- Diet
- Small schooling fish, anchovy, sprat
- Status in Georgia
- Resident, numerous in winter
- Size
- 1.4–1.9 m, up to 76 kg
- Habitat
- Coastal sea, river mouths
- Family
- Phocoenidae
- Conservation
- EN in Georgia (2021); EN in the Black Sea (2008)
The harbour porpoise (Phocoena phocoena) is a small, stocky cetacean with a barely visible beak and a low, triangular dorsal fin. It is 1.4–1.9 m long. The Black Sea has its own, almost isolated subspecies, P. p. relicta, whose ancestors arrived here 5,000–8,000 years ago. The coastal waters from Anaklia to Sarpi are an important wintering ground: about 18,000 harbour porpoises were counted here in the winter of 2014. The main threat is fishing nets, which kill thousands of them in the Black Sea every year. If a small triangular fin shows at sea and the animal does not leap, you are most likely looking at a harbour porpoise.
Identification
Harbour porpoise: how to identify it
A small, stocky cetacean with a barely visible beak. The back is dark grey, the belly white, and the dorsal fin low and triangular. You can tell it from the dolphins by the missing beak, the triangular fin and its small size.
Adults are 1.4–1.9 m long. Females are heavier than males: a female reaches up to 76 kg, a male about 61 kg. The body is thickest just in front of the dorsal fin. Black Sea animals have a smaller body and skull than Atlantic ones.
The back, flippers and tail are dark grey, and the sides are a lighter grey with fine speckles. The belly is much whiter, and grey stripes often run along the throat. The beak is barely visible, so the head looks shorter than a dolphin's.
The common dolphin is 1.9–2.5 m long, with a long beak and a pale hourglass patch on its sides, and it often leaps clear of the water. The bottlenose dolphin is 2–4 m long, plain grey, with a tall, hooked fin. The harbour porpoise is smaller than both and rarely leaps. At sea, look at the fin first: a low triangle belongs to the porpoise.
Colour
Swatches are illustrative. Do not identify a species by colour alone.
Often confused with
The harbour porpoise is a coastal animal: it lives near the shore, in bays and at river mouths in temperate and cold seas. It is found in the North Atlantic, the North Pacific and the Black Sea. The Black Sea subspecies, P. p. relicta, lives in the Black Sea and the Sea of Azov, also enters the Sea of Marmara, and has been cut off from Atlantic porpoises for thousands of years. In Georgia it lives in the coastal waters from Cape Anaklia to Sarpi all year round. This strip is its wintering ground: about 1,200 harbour porpoises were counted here at the start of autumn 2014, and about 18,000 the following winter. In the winter of 2016, 16,715 were counted, about 9,500 in spring, and about 3,200 in the summer of 2019. It feeds mainly at the mouths of the Enguri, Rioni, Khobistskali, Supsa and Chorokhi.
The harbour porpoise map combines public iNaturalist observations. Regions are taken from the records-by-region table, and the status column separates regions with enough records from regions with too few records. Record counts reflect observation effort rather than population density. Records are still too few, and no region has enough records yet.
Data: Reptiles.ge + iNaturalist · Methodology
- Field observation
- Region with records
The harbour porpoise eats small schooling fish, and in some places squid and crustaceans too. It often hunts close to the sea floor, but stays near the surface when hunting sprat. In Georgian waters large schools of anchovy winter and spawn in winter and spring, giving porpoises plenty of food. In the south-eastern Black Sea it hunts mainly at night and is most active from January to May, during the anchovy migration. It finds prey by echolocation: it sends out short clicks and listens for the echo. As a rule it hunts alone, though sometimes a group herds a school of fish together. A young animal needs 7–8% of its own body weight in food every day.
The harbour porpoise is a solitary animal: it usually swims alone or in groups of up to five. It rarely leaps out of the water, so it is hard to spot. In Georgian waters it is easiest to see in late autumn, winter and early spring, when it is numerous here. A dive usually lasts one minute, sometimes as long as five. In the Black Sea the breeding season peaks in May–July. In Georgian waters porpoises have been seen with calves under 3 months old, and females in late pregnancy have stranded on the shore. The area is therefore also regarded as a place for mating and raising young calves. Pregnancy lasts 10–11 months. A newborn is 67–85 cm long and weighs 6.4–10 kg, and it suckles for 8–12 months. Females mature in their third or fourth year and may calve every year for several years in a row. In the wild it lives 8–13 years on average, exceptionally up to 20.
Worldwide the harbour porpoise is not threatened (LC, 2020). The Black Sea subspecies, however, is Endangered (EN, 2008), and the provisional 2018–2021 reassessment kept that category. The 2021 assessment for the Georgian Red List also rates it Endangered (EN). The Black Sea population is genetically uniform and does not split into separate subpopulations, so it was assessed as one population. Porpoise hunting in the Black Sea went on from the 1830s and killed tens of thousands of animals a year. It was most intense in 1929–1966. In 1966 the USSR, Bulgaria and Romania banned it, while in Turkish waters it continued until 1983. A genetic estimate puts the population decline in the second half of the 20th century at about 90%. Today the main threat is bottom-set nets for turbot: by one estimate, 11,826–16,200 harbour porpoises die in them in the Black Sea every year. In Georgian waters too the greatest threat is accidental capture in nets, along with disease, severe storms and the decline of prey fish. In 1989–1990 infections caused a mass die-off. The Black Sea population is listed in Appendix II of the Bonn Convention.
Related guides
Continue with related pages
Yes. The harbour porpoise lives in Georgia's coastal waters from Cape Anaklia to Sarpi all year round. It is especially numerous in winter: about 18,000 were counted in the winter of 2014, and about 3,200 in the summer of 2019. Here it hunts the wintering schools of anchovy.
By the fin and the head. The harbour porpoise has a low, triangular dorsal fin and a barely visible beak. The common dolphin has a long beak and an hourglass patch on its side, and the bottlenose dolphin a tall, hooked fin. Both dolphins are larger than the porpoise, and the porpoise rarely leaps out of the water.
Not only in Georgian. The English porpoise comes from Latin porcopiscus, “pig fish”. Danish marsvin and Middle Dutch mereswijn mean “sea swine”. In Russian too it is called морская свинья.
Small schooling fish. In Georgian waters its plentiful food in winter and spring is anchovy, which winters and spawns here. In the south-eastern Black Sea it hunts mainly at night. It finds prey by echolocation and usually hunts alone.
No. The harbour porpoise is a small cetacean and is no danger to people. It is the other way round: human nets are dangerous to it. If you find a harbour porpoise caught in a net, stranded or injured, call 112.
Yes. In Georgia it is Endangered (EN, 2021), and the Black Sea subspecies is Endangered globally too (EN). Hunting it was banned in 1966, and in Turkish waters in 1983. Today the main threat is nets, which kill thousands of harbour porpoises in the Black Sea every year.
References
What this profile is based on
Species profiles are compiled from peer-reviewed literature and established biodiversity databases, and are reviewed as new taxonomic and conservation data become available.
Prepared by the Reptiles.ge editorial team from the sources listed here.
