British Divers Marine Life Rescue
British Divers Marine Life Rescue
British Divers Marine Rescue

Dolphins & Porpoises

Species most likely to be encountered.

Common Dolphin (Delphinus delphis)

Common dolphinA pelagic species, measuring up to 2.5 metres, black/dark grey dorsally, white ventrally, with a characteristic ‘hour glass’ pattern along its flanks and a long ‘beak’ (rostrum). This species is found in the western English Channel, off south-west and north-west England, the west coast of Scotland, Ireland and in the Irish Sea. Sometimes it is found in the North Sea and the eastern English Channel, but this is rare. Common dolphins have a gestation period of 10 to 11 months, calves are born from spring to autumn, measuring 0.8 - 0.85 metres, are dependent for up to 19 months and are weaned at nearly 1.5 metres in length. The species is generally found in groups of 100+ in the Atlantic and they feed on fish, e.g. herring, sardines and pilchard, and squid.

Harbour Porpoise (Phocoena phocoena)

Harbour PorpoiseA coastal species, measuring up to 2.0 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 mainly in June and July, measuring 0.7 to 0.9 metres, and are dependent for 7 to 10 months. They are weaned when approximately 0.90 to 0.95 metres long. The species is found generally in small groups of a few individuals, mainly feeding on shoaling fish (herring, sprats and whiting).

Long-finned pilot whale (Globicephala melas)

Long-finned pilot whaleA pelagic species, measuring up to 6.0 metres in length, grey-black/dark brown in colour, with a grey/white patch on the chin, bulbous head, no ‘beak’, and a low rounded dorsal fin which is set well forward. This species is widely distributed in the North Atlantic, entering British coastal waters seasonally, primarily off northern Scotland, western Ireland and in the western English Channel. Long-finned pilot whales have a gestation period of 14.5 to 15 months. Calves are born between July and August, measuring 1.8 metres, are dependent for up to 22 months, and measure approximately 2.3 to 2.5 metres in length when weaned. The species is found in groups of tens to hundreds of individuals, and they feed primarily on squid, but will also supplement their diet with a wide variety of fish.

White-beaked dolphin (Lagenorhynchus albirostris)

White-beaked dolphinA pelagic species measuring up to 3.1 metres in length. Back is dark grey/black, belly white/light grey, with light grey/white patches/stripes on sides, in front of dorsal fin and over back and tail stock behind dorsal fin, with a stubby ‘beak’, which is usually white in colour. This species is found primarily off Scotland and the Atlantic seaboard of Britain and Ireland and also in the northern and central North Sea. Whitebeaked dolphins’ calves are born in summer and early autumn, measuring 1.2 to 1.6 metres. The species is found in variable sized groups (most commonly less than 100), and feeds primarily on herring, sprats, cod and whiting, but will also take squid and crustaceans.

Atlantic white-sided dolphin (Lagenorhynchus acutus)

Atlantic white-sided dolphinA pelagic species measuring up to 2.7 metres in length, black dorsally, white ventrally, with a white side stripe, becoming yellow/ochre at the rear, and a grey stripe below these. Has a stubby ‘beak’. This species is found primarily off the north and north-west coasts of Scotland and in the northern North Sea, and rarely in the English Channel and southern North Sea. Atlantic white-sided dolphins have a gestation period of 10 to 12 months, calves are born in early summer, measuring 1.0 to 1.3 metres, and are dependent for up to 18 months. The species is found in variable sized groups, and they feed primarily on small shoaling fish, e.g. herring, smelt and juvenile mackerel, but will also take squid.

Bottlenose dolphin (Tursiops truncatus)

Bottlenose dolphinA coastal or pelagic species, measuring up to 4.0 metres in length, generally dark grey/brown dorsally, light grey on sides and white ventrally, with a stubby ‘beak’. This species is found in small resident populations in British coastal waters, located in the Moray Firth, Cardigan Bay, south-west England and western Ireland. Bottlenose dolphins have a gestation period of 12 months. Calves are born in the spring and summer, measuring 1.0 to 1.3 metres, and are dependent for up to 18 months and are around 1.75 metres in length when weaned. The species is found in groups of less than 100 individuals in British waters, and they feed on a wide variety of fish, including salmonids, herring, sprat, mullet and mackerel, squid and cuttlefish.

Striped dolphin (Stenella coeruleoalba)

Striped dolphinA pelagic species measuring up to 2.5 metres in length, black dorsally, white ventrally, with a dark stripe running from the eye to the anus and from the eye to the pectoral flipper and a white V-shaped blaze running from the eye up towards the dorsal fin and back towards the tail. Has a fairly long ‘beak’. This generally more southerly distributed species is occasionally found in the western English Channel, off south-west England and Ireland, and rarely in the Irish Sea and off the coast of Scotland. Striped dolphins have a gestation period of 12 to 13 months, calves are born in the summer and winter, measuring 1.0 metres, and are dependent for up to 18 months. The species is found usually in groups of 100 to 500 individuals, and they feed on midwater fish, squid and shrimp.

Risso's dolphin (Grampus griseus)

Risso's dolphinA pelagic species measuring up to 3.8 metres in length, dark grey dorsally and on sides, lightening with age to light grey, particularly on head, pale grey/white belly; multiple scratches and scars; no ‘beak’. This species is seen off the north and west coasts of Scotland, west coast of Ireland, Irish Sea and south-west England. It is seen rarely in the North Sea. Risso’s dolphins have a gestation period of 13 to 14 months. Calves are born in the summer, measuring 1.2 to 1.5 metres. The species is found generally in small groups of a few dozen animals, although occasionally herds of up to several thousand are seen. They feed primarily on squid (and octopus).