Harbour porpoise

  • Scientific name: Phocoena phocoena
  • Length: up to 1.9m
  • Marine mammal type: cetacean
  • Family: Phocoenidae
  • IUCN Conservation status: Least concern
  • Protected by: UK Habitats Directive


A coastal species, measuring up to 1.9 metres long, dark grey dorsally, white ventrally, with a blunt head with no beak, small rounded pectoral fins and a small central triangular dorsal fin. This species is found in the central and northern North Sea, off the west coast of Scotland, west coast of Wales and south-west coast of Ireland, in the southern Irish Sea and occasionally in the southernmost North Sea and English Channel. Harbour porpoises have a gestation period of 11 months, calves are born from May to August measuring 0.6 to 0.75m, and are dependent for 7 to 10 months. They are weaned when approximately 0.90 to 0.95m long. The species is found generally in small groups of a few individuals, and they feed mainly on shoaling fish e.g. herring, sprats and whiting.

Where to see them

This species is found all around the UK coast. It forages in coastal waters and is easily seen from the shore or a boat.

It enters estuaries frequently including the Thames, and can be seen as far inland as London. It is often see in small groups or singularly, but is a shy elusive animal to spot.


The harbour porpoise is one of the most common cetaceans BDMLR gets called to, mainly as they are one of our most abundant and widespread species. They are normally adept at navigating tidal areas and estuaries, so it is unusual for them to strand through navigational error, and more likely that there is a serious underlying health problem.

They are also a species attacked by bottlenose dolphins, which has led to occasional live strandings too. It is still unclear why this happens, but there are theories ranging from competition for space and food resources as well as misdirected sexual aggression. Common dolphins, striped dolphins and the calves of Risso’s dolphins and pilot whales are also known to have fallen victim to these attacks in the UK too.

What to do if you find a stranded animal?

A whale, dolphin or porpoise stranded on the beach is obviously not a usual phenomenon. These animals do not beach themselves under normal circumstances, and they will require assistance. Please DO NOT return them to the sea as they may need treatment and or a period of recovery before they are fit enough to swim strongly.

01825 765546 (24hr)
RSPCA hotline (England & Wales): 0300 1234 999
SSPCA hotline (Scotland): 03000 999 999

You will receive further advice over the phone, but important things you can do to help are:

  • Support the animal in an upright position and dig trenches under the pectoral fins.
  • Cover the animal with wet sheets or towels (even seaweed) and keep it moist by spraying or dousing with water.
  • Do NOT cover, or let any water pass down the blowhole (nostril), sited on top of the animal’s head. This will cause the animal great distress and could even kill it.
  • Every movement around a stranded animal should be quiet, calm and gentle. Excessive noise and disturbance will only stress it further.
  • Estimate the length of the animal and look for any distinguishing features that may give clues as to the species you are dealing with.
  • Look for signs of injury and count the number of breaths (opening of the blowhole) over a minute – this can give important clues as to how stressed the animal is.
  • Take great care when handling a dolphin, porpoise or whale; keep away from the tail, as it can inflict serious injuries – this is particularly the case with whales and it is advisable to leave handling larger whales until experienced help arrives. Avoid the animal’s breath, as it may carry some potentially nasty bacteria.
  • Provide information: Give the hotline an exact location for the animal – this can save valuable and perhaps critical time. If you have a mobile, give the number to the hotline.
  • Give an accurate description of the animal, including its breathing rate, and whether it is in surf, on rocks or sand, in the shade or in the full glare of the sun.
  • Information on weather conditions and sea state are also helpful.
  • The hotline should be informed of any attempts already made to push the animal back into the sea.
  • Maintain control.
  • Keep all contact, noise and disturbance to a minimum.
  • Under no circumstances, release the animal into the sea before the rescue team has arrived. It is fine to support a smaller dolphin or porpoise in the water, as long as the blowhole is kept above the water at all times, and as long as it is carried to the water carefully, e.g. in a tarpaulin (do NOT drag it or lift it by its fins or tail).
  • However, actually releasing the animal before it has received an assessment and first aid from experienced personnel can do more harm than good.

If you find a dead cetacean

The Cetacean Strandings Investigation Programme (CSIP) collects a wide range of data on each stranding found on UK shores. If you discover a dead animal, please contact the CSIP hotline and give a description of the following where possible:

  • Location and date found
  • Species and sex
  • Overall length
  • Condition of the animal
  • Your contact details should further information be needed

Digital images are extremely helpful to identify to species, as well as ascertaining whether the body may be suitable for post-mortem examination. 

CSIP has produced a useful leaflet that can be downloaded by clicking here.

CSIP hotline: 0800 6520333. Callers are given a number of options to ensure they reach the correct department. You can also use this number to contact BDMLR as there is an option for live animal strandings that transfers directly to us.