Atlantic white-sided dolphin

© L. Drysdale

Lagenorhynchus acutus


Size: 2 - 2.8m

Key feature: White and yellow stripe

Atlantic white-sided dolphins are robust and have an abnormally thick tail stock. They have a distinct colour pattern; a dark back and dorsal fin, grey sides and white underbelly. They also have a thin white stripe along their flank, which goes to a yellow-tan colour on the tail stock. They have a slopping head and a tall curved dorsal fin. Atlantic white-sided dolphins are easily mistaken with white-beaked dolphins.


Atlantic white-sided dolphins are very energetic and fast swimmers. Although less agile than the common or striped dolphin, they are often seen breaching and tail slapping. They are often seen in large groups of up to 50 individuals and also associate with other cetaceans.


Atlantic white-sided dolphins are distributed throughout temperate and subarctic waters in the north Atlantic. They can sometimes be seen offshore to the west of Britain and Ireland. They are uncommon to see and tend not to come close to land. Although the southerly limit of their distribution is the north of Spain, they are occasionally seen on the UK side of a trip through the Bay of Biscay. They have been seen more frequently in the North Sea, with the most recent sighting occurring in 2016 by Wildlife Officers in the North Sea.


The major threats towards Atlantic white-sided dolphins include entanglement in fishing gear, bycatch and the overfishing of their prey.

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