Atlantic white-sided dolphin (Lagenorhynchus acutus)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help



Lagenorhynchus acutus is a toothed whale and can be recognised as such by the single blowhole and the presence of teeth (rather than baleen). It is a member of the dolphin family with a characteristic prominent median notch in the flukes, a smooth crease-less throat and sharply pointed teeth. The Atlantic white-sided dolphin reaches up to 2.8 m in length. It has moderately long and slender flippers and small tail flukes. The dorsal fin is tall, large and located on the middle of the back. The head is smoothly sloping with a distinct but small snout. It has a complex clearly demarcated colour pattern. It is black to dark grey on the back from the upper beak to the tail, changing sharply to light grey on the sides. The lower jaw and belly, as far as the anus, are white. A distinct white band is visible on the flanks under the dorsal fin between the black and light grey colouration, which turns into an olive-yellow stripe towards the rear at the lower margin of the dark dorsal colouration. A dark line runs from the upper beak to, and surrounding, the eye.

Recorded distribution in Britain and Ireland

Found off the coasts of Scotland, north-east England, south-west England and Ireland and off north-west Ireland. Occasionally seen in the North Sea, English channel and all other British waters.

Global distribution

Temperate and subarctic North Atlantic. Cape Cod to southern Greenland, Iceland, Svalbard, the Norwegian coast, north and western British Isles, and occasionally from the Norht Sea and English Channel, the Bay of Biscay and Western Spain.


The Atlantic white-sided dolphin is an oceanic species prefering deep waters on the outer continental shelf and slope.

Depth range


Identifying features

  • Slender body up to 2.8 m in length.
  • Tall, large dorsal fin located on the middle of the back.
  • Very deepened tail stock.
  • Dorsally dark grey to black, laterally light grey and ventrally white in colour.
  • Black line running from the upper beak to the eye.
  • Short slender flippers.
  • Gently sloping head with a short, thick beak.
  • Straight mouthline.

Additional information

Atlantic white-sided dolphins are usually found in large pods of up to several thousand individuals. Mixed schools with other species including white-beaked dolphins, Lagenorhynchus albirostris, have been recorded. Their surface behaviour is typical of dolphins with acrobatic leaps but bow-riding uncommon. Dive duration is unknown (Kinze, 2002).


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  2. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  3. Jefferson, T.A., Leatherwood, S. & Webber, M.A., 1994. FAO species identification guide. Marine mammals of the world. Rome: United Nations Environment Programme, Food and Agriculture Organization of the United Nations.

  4. Kinze, C. C., 2002. Photographic Guide to the Marine Mammals of the North Atlantic. Oxford: Oxford University Press.

  5. Reid. J.B., Evans. P.G.H., Northridge. S.P. (ed.), 2003. Atlas of Cetacean Distribution in North-west European Waters. Peterborough: Joint Nature Conservation Committee.


  1. Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: accessed via on 2018-09-38

  2. Fife Nature Records Centre, 2018. Fife Nature Records Centre combined dataset. Occurrence dataset: accessed via on 2018-09-27.

  3. Hebridean Whale and Dolphin Trust, 2018. Visual sightings data set 2003-2017. Occurrence dataset: accessed via on 2018-09-27.

  4. NBN (National Biodiversity Network) Atlas. Available from:

  5. Norfolk Biodiversity Information Service, 2017. NBIS Records to December 2016. Occurrence dataset: accessed via on 2018-10-01.

  6. North East Scotland Biological Records Centre, 2017. NE Scotland marine mammal records 1800-2010. Occurrence dataset: accessed via on 2018-10-01.

  7. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-07-14

  8. Outer Hebrides Biological Recording, 2018. Vertebrates (except birds, INNS and restricted records), Outer Hebrides. Occurrence dataset: accessed via on 2018-10-01.

  9. South East Wales Biodiversity Records Centre, 2018. SEWBReC Mammals (South East Wales). Occurrence dataset: accessed via on 2018-10-02.

  10. Whale and Dolphin Conservation, 2018. WDC Shorewatch Sightings. Occurrence dataset: accessed via on 2018-10-02.


This review can be cited as:

Barnes, M.K.S. 2008. Lagenorhynchus acutus Atlantic white-sided dolphin. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 14-07-2024]. Available from:

Last Updated: 02/06/2008