A small porpoise of cool Northern Hemisphere waters. It uses bays and estuaries and mainly eats schooling fish.
It has a stocky body, short blunt beak and triangular dorsal fin. The back is dark gray and the belly and throat are white.
Near Prince Rupert on Canada’s west coast, a study compared harbour porpoise sounds with vessel-location data in a roughly 2-km² area of Chatham Sound.
Acoustic records from 2020–2022 showed shorter periods of both foraging-related click trains and other click trains when more vessels were present. More medium- and fast-moving vessels, traveling at least 2.5 m/s (about 9 km/h), were associated with lower activity in both categories. Tugboats were linked to lower foraging and non-foraging activity, while passenger vessels were linked to lower non-foraging activity. The researchers separated foraging click trains from other sounds by the spacing between clicks. They recorded sound activity, not the positions or swimming paths of individual porpoises, so the results describe this area near the port.
IUCN Red List of Threatened Species · Least Concern (LC) · Global
At the global level, the harbour porpoise is listed as Least Concern (LC) on the IUCN Red List. The assessment date is 19 May 2020, and an amended version was published in 2023. The global population trend is recorded as unknown. HELCOM’s 2024 Baltic Sea assessment classified the Baltic Proper population as Critically Endangered (CR) and the Belt Sea population as Endangered (EN). HELCOM’s species information sheet identifies fisheries bycatch as the greatest concern for Baltic porpoises and contaminant pollution as a threat. Gillnets are thought to account for most bycatch; underwater noise, shipping and prey depletion are also listed as regional threats.