Long-Finned Pilot Whale 

	Long-finned pilot whale Globicéphale noir de l’Atlantique Globicephala melas Other names: pothead, blackfish

Description

• Pot-shaped head, prominent melon

  Richard Sears

• No visible beak

• Large-based, backward-stretching, falcate dorsal fin set ahead of mid-body

• General colour: black or dark brown

• White or light grey saddle on the back, behind the dorsal fin

• Grey, anchor-shaped mark on the throat

• Long, thin pectoral fins

When it surfaces: Its blow is rarely visible. Its head, with the characteristic melon, its dorsal fin, and sometimes its tail, appear in succession. Pilot whales are often observed in groups.

A global network of large bolar hats

Although they are only occasional in the St. Lawrence, encounters with pilot whales are impressive. With its dark skin, massive body and prominent forehead, it does not resemble a dolphin. The name pilot whale refers to strandings of dozens of whales at a time; their gregarious behaviour appears to push members of a group to follow a lead, or “pilot” whale to certain death. 

Population, range and habitat

In the St. Lawrence: The North Atlantic long-finned pilot whale is a summer resident of the Gulf of St. Lawrence, most often seen around the Gaspé Peninsula and along the East Coast of Newfoundland. Based on aerial surveys carried out in the Gulf and along the Northeast Coast of Cape Breton in 1995, the St. Lawrence population is estimated at 1600. Visits to the Estuary are rare. A few isolated incidents of stranded individuals have been recorded in the St. Lawrence, including a mass stranding in the Estuary in 1920.

Migration: Pilot whale migration is not well documented. In the western North Atlantic, these whales tend to gather offshore in winter and spring. They approach the coast and bays in summer and fall. Their movements track those of their prey.

Worldwide: Pilot whales are present in the temperate and sub-Arctic waters of the North Atlantic and in the western portion of the Mediterranean Sea. There are an estimated at 10 000 long-finned pilot whales in the western North Atlantic. Their numbers in the centre and eastern Atlantic Ocean are estimated at several hundred thousand. The Southern Hemisphere subspecies of long-finned pilot whale is circumpolar. The short-finned pilot whale Globicephala macrorhynchus is smaller and is a distinct species that inhabits the warm waters on either side of the Equator.

Behaviour

Feeding: The North Atlantic long-finned pilot whale feeds mainly on squid and mackerel in the water column. It will occasionally eat shrimp and other species of fish, such as cod and plaice. It sometimes swims with other species, like white-sided dolphins while hunting.

At the surface: Pilot whales are quite fast and can swim at speeds of up to 35 km/h when pursued by a predator. Pilot whales swim by successive leaps, much like dolphins. They are capable of performing breaches, but rarely do. They do not approach boats nor do they play in ship’s wakes or bow waves. They do spyhop and slap their tails against the surface. They often remain immobile at the surface when resting.

While diving: Dives last on average 5 to 10 minutes to depths of 30 to 500 m where they hunt their prey. They are capable of diving to 1000 m and remaining below the surface for 15 minutes at a time.

Social behaviour: The Atlantic long-finned pilot whale is a gregarious animal. Herds of several hundred scattered around the ocean are composed of stable family units of 10 to 20 whales. These units area matriarchal, consisting of adult females and their offspring. Males generally leave the family unit to mate; they eventually return to their birth group. Males take on the role of protectors against predators, which explains their shorter life span. During the mating period, males can wound and even kill each other by biting and ramming, or head butting. Large groups have a high social cohesion. Mass strandings involving several hundred animals are not rare. A number of hypotheses have been put forward to explain these mass strandings. Could they be caused by navigational errors, infectious diseases or parasites within the group, an extreme sense of loyalty towards a member of the group who is sick, injured or in distress? Pilot whales also associate with groups of dolphins and other, larger cetaceans.

Vocal behaviour:Its vocal repertoire is quite diverse and complex; it is composed of whistles, clicks, pulsating sounds, growls, cries and rumblings. These sounds are used for communication and echolocation.

Reproduction

Male pilot whales attain sexual maturity between 12 and 16 years of age, females between six and 10. Mating takes place between April and September. Gestation lasts for 12 months. Calves are nursed for three years.

About scientific research

Hal Whitehead’s Research Group from Dalhousie University in Nova Scotia has been conducting research on long-finned pilot whales off Cape Breton since 1998. The group’s catalogue consists of 987 individuals photo-identified using notches and marks in the dorsal fin. The analysis of acoustic recordings is underway and should permit researchers to determine if dialects exist for family units, as is the case with killer whales.

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	Long-Finned Pilot Whale