Harbour Porpoise


  • Harbour Porpoise
  • Harbour Porpoise
  • Harbour Porpoise
  • Harbour Porpoise

Harbour porpoises frequent coastal zones of the Gulf and the Estuary in the summer (end of June to end of September).

They can often be found in fjords, bays, estuaries and ports (hence their name).

In the Gulf of St. Lawrence, the population is estimated at over 20,000 individuals.

The harbour porpoise inhabits temperate waters and subarctic waters (coastal) of the Northern Hemisphere.

The species is also present in the North Pacific.

There is even a population in the Black Sea.


The harbour porpoise does appear in the List of threatened or vulnerable species in Quebec.

The Northwest Atlantic population is listed as “special concern” by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).

The International Union for Conservation of Nature’s” (IUCN) List has designated the harbour porpoise of “least concern”.

The harbour porpoise searches for its food in the water column (small schooling fish such as capelin, herring, pollock, mackerel).

It also feed on on the seabed (squid and crustaceans).

Illustrated species: (from high to low, from left to right): mackerel, squid, herring, capelin, shrimps.

Harbour porpoise cows are amongst the few cetaceans that are able to give birth every year.

Harbour porpoises are gregarious.

Photo credit: GREMM

It lives in small groups of 2 to 5 individuals that can gather in herds of a few dozen or even a few hundred individuals.

These groupings are linked to feeding.

The porpoise emits repeated clicks but also low-pitched sounds which are believed to be used for communication and echolocation.

Its rapid swimming movement creates the impression that it is rolling on the surface.

The harbour porpoise can cover vast distances in a day.

They rarely leap out of the water.

Photo credit: GREMM

Harbour porpoises are wary and not usually curious toward boats.

Their short dives generally do not exceed 5 minutes, reaching depths varying between 15 and 130 m.

Harbour porpoises’ coastal habits and our fishing methods don’t make a good match. In the early 1990s, thousands of incidental catches in fishing nets prompted fears for the species’ survival. Mortalities have in all likelihood declined since the cod fishing moratorium implemented in the St. Lawrence in 1993, but the threat may still be a concern for the population’s recovery.

The results of a 2001-2002 research have revealed a drop in the incidence of the gillnet bycatch of harbour porpoises. Yet, these occurrences are by no means insignificant. Further data will be collected to gain a better understanding of the problem of bycatch in the St. Lawrence and determine how to best mitigate impacts of the groundfish fishery on harbour porpoises.