Dolphins & Porpoises of the North Atlantic

The harbour porpoise is a tiny cetacean, measuring no more than 1.6 metres (5.2 feet). What they lack in stature, they make up for in numbers, with a sizeable population in the Gulf of Saint Lawrence and throughout the North Atlantic region, all the way to south Greenland and Iceland.

The species roams coastal areas and shallow banks in search of its main preys of schooling fish—capelin and herring in particular. They also eat a variety of other fish species and squid.

These diminutive porpoises are not seen easily. Their small size and dark colour them easy to miss, particularly in rough seas. If startled by an approaching ship, they may speed up and cause much upward splashing as they race away, with little hint of a body shape. These splashes are sometimes referred to as rooster tails by sailors. Dolphins may also cause such splashing, but are large enough to spot and often jump out of the water.

On a calm day, harbour porpoises can be seen rolling at the surface, showing their small black bodies and prominent triangular dorsal fins.

White-beaked dolphins are best known for the white tips of their beaks, but this is not always a good identifying feature because, in fact, not all individuals have a white beak! The white beak is more frequently seen in individuals from the European North Atlantic, where the species was named; in Canadian waters, the proportion of white-beaked individuals is reduced. Instead, they are best told from the light grey patches on their flanks and behind their prominent dark dorsal fin.

White-beaked dolphins often travel in groups, sometimes by the hundreds when their prey is concentrated, but usually in smaller groups of a few tens or less. They can jump clear out of the water (a behaviour called porpoising) while they swim.

They like squid, but also eat octopus, herring, cod, and capelin. You are most likely to see them in the Gulf of Saint Lawrence, along the coasts of Newfoundland and Labrador, as well as in waters between South Greenland and Iceland.

Another common dolphin of the region is the Atlantic white-sided dolphin. It has similar characteristics to the white-beaked dolphin, like its black back and head and falcate dorsal fin, but it lacks the light grey behind the dorsal fin. When seen porpoising, you’ll notice two distinct bands on the rear, a white band along the flanks (which gives it its common name), followed by a yellow one along the tail stock. If it jumps high enough, it also shows a white throat and belly.

White-sided dolphins are slightly smaller than the white-beaked, measuring up to 2.7 metres (nine feet). They most often form large groups, which can number from fifty to 500 individuals. They also eat schooling prey—squid, herring, and capelin in particular—as well as sand lance, striped bass, mackerel, and shrimp.

You are most likely to see them in late summer and fall in the maritime provinces, the Gulf of Saint Lawrence, and in the North Atlantic from the coasts of Newfoundland and Labrador to southern Greenland and Iceland.

Bottlenose dolphins are the archetypal dolphins, best known from aquaria where they are trained to show their energetic behaviours, though these can also be seen in the wild. They are active jumpers, porpoising quite high over the water when they are feed on their coastal prey. This species is rarely seen in Atlantic Canada, being a temperate and tropical species, but some occupy coastal waters and estuaries around the United Kingdom, Ireland, and France.

Adults are quite large for dolphins, reaching four metres (thirteen feet). Their long bottle-like beak gives them their common name. Adults and are relatively uniform in colour, either a bluish- or brownish-grey, with a somewhat darker back than the underside, while their young are a lighter brown.

Pods of bottlenose dolphins often work as a team to herd schools of fish into a tight ball before charging the ball to capture them. They are also known to whack fish with their tail flukes while they hunt. They appear not to be selective about the schooling prey they hunt and also eat squid and octopus.

So, there you have it: the varied dolphin and porpoise species you’re most likely to see on Adventure Canada expeditions. Make sure you go out on deck as often as you can, and keep your eyes peeled—you may just be lucky enough to be treated with sightings of some of these wonderful species, plus whales, seals, and birds!