Bottlenose Dolphin

Bottlenose Dolphin: Tursiops truncatus

IUCN Status: least concern

Status and distribution summary:

Occupies low to mid latitude, temperate to warm waters around the world, including most semi-enclosed seas, and is found both inshore and in deep water. Scottish populations are among the most northerly in the world.

Exploitation:

Persecuted by fishermen in the tropics as a competitor, included in the Japanese drive hunts, where thousands may be taken each year. Some fisheries by-catch in European waters, though no data is available on scale. And is the most common dolphin kept in captivity.

Where it is seen:

Occurs in any part of the Bay and outer channel, but mainly close to shore or over the upper continental shelf slopes. Inshore pods occur around the Breton archipelagos, and off the Dorset and Devon coasts. Some groups can be seen over very deep water.

Frequency of sightings:

Regularly seen throughout the year, but especially in summer. Occurs usually in small groups of up to 20.

Recognition:

Large, robust dolphin, adult males can be up to 4 metres in length. Can appear surprisingly large at sea.

Grey upper parts, often with blotching. Can appear black in dull light. Underside near white, with paler grey flanks. Delineation between these can be quite marked.

Short but distinct beak, can be quite stubby.

Well proportioned falcate dorsal fin is positioned centrally. Perhaps more raked back than in other species of dolphin occurring in the region.

Behaviour:

Occurs in groups of usually less than 20, but very occasionally much larger, and sometimes joins with other species.

Often seen slow swimming when travelling, or milling, but can be quite demonstrative, leaping clear of the water in fast swimming. In slow swimming, often only the back breaks the surface.

Will readily come to ships to bow and wake rides.

Confusion species:

  • Risso's Dolphin; is also grey, but has a thinner and proportionally taller dorsal fin. When seen, it has a very snub nosed appearance, with no beak.
  • Other dolphins in the region are strongly patterned.