Fin whale

Description

  • Long, streamlined and flexible body
  • On the right side, colour pattern on the rear of the head with distinctive gray, white, brown and black chevrons
  • Asymmetrical colouration of the lower jaw: white on the right, dark on the left
  • Variably-shaped dorsal fin, located in the second tier toward the rear of the body
  • Relatively small, pointy pectoral fins
  • Ventral grooves covering from the throat to the navel

When it surfaces: Its audible and easily visible column-shaped spout can reach 4 to 6 m high. The dorsal fin appears shortly after the blow.

Images

Rorqual commun

Balaenoptera physalus

Other names: Finback whale, common finback, finner, razorback, flathead, common rorqual, greyhound of the sea, herring whale

Suborder: Baleen whales (Mysticeti)

Length: 18 to 24 m, up to 27 m in the Southern Hemisphere

Weight: 40 to 50 t

Social behaviour: Solitary, in pairs or in groups

Life expectancy: 80 to 100 years (140 years for the oldest specimen captured)

Dive time: 5 to 15 minutes, up to 25 minutes

Observations: Regular in summer in the Gulf and Estuary

Global range: From the Arctic to the Antarctic

Global population: Probably in the order of 100,000 individuals

Status in Canada: Special Concern


A fast, flexible and powerful giant

The fin whale is the second longest of all cetaceans, after the blue whale. Certainly the fastest of the the great whales, it is nicknamed the “greyhound of the sea”. In the St. Lawrence, certain individuals are faithful to their summer feeding grounds and return every year, while others have been observed just once or twice. In the Estuary, a significant whale-watching industry revolves around this species, which can even be sponsored.

Population, range and habitat

In the St. Lawrence

Between May and late November, it is a seasonal resident of the Estuary and Gulf, where it comes to feed. Fin whales congregate in regions where food is abundant due to various oceanographic phenomena (thermal fronts, topography and upwellings), notably at the head of the Laurentian Channel (between Tadoussac and Les Bergeronnes). The population of the Gulf (excluding the Estuary) was estimated at 380 individuals (per aerial surveys conducted by Fisheries and Oceans Canada in 1995 and 1996, which did not account for animals below the surface).

Migration

Migratory movements and wintering grounds are poorly known. For reproduction, fin whales seem to migrate short distances toward the lower latitudes of the North Atlantic, without ever forming large pods.

In the world

Fin whales of the St. Lawrence are part of the North Atlantic population, whose numbers are not clearly known, with estimates having been made difficult by the expanse of its range and the risks of confusion with the sei whale. Nevertheless, a compilation of estimates suggests that the population of the North Atlantic may be as high as 56,000 individuals. One study demonstrated the genetic distinctions between fin whales of the Northwest Atlantic, Northeast Atlantic, and the Mediterranean. The species is present in all of the world’s oceans, from temperate waters to polar latitudes.

Status

The fin whale was designated a “special concern” species by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 1987. Whaling, which ended in 1972, had taken a considerable toll on the number of fin whales on the Canadian East Coast and particularly on the Scotian Shelf. The lack of knowledge on this species justifies the status proposed.

The International Union for Conservation of Nature (IUCN) has listed the species as “vulnerable”. In the United States, the fin whale is considered “endangered” under the Endangered Species Act, and appears in the List of threatened or vulnerable species in Quebec under the Act Respecting Threatened or Vulnerable Species.

Behaviour

Feeding

The fin whale is a gulper, with a varied diet composed of planktonic crustaceans and small schooling fish (herring, capelin). It sometimes surface feeds where it performs circular or semi-circular manoeuvres, rolling its body onto its side (often the right side). Indeed, it is the only cetacean and one of the few vertebrates to exhibit an asymmetrical colour pattern on its head. On the right side, the lower jaw, oral cavity, tongue and throat are lighter in colour, bordering on white. Thus, the fin whale is believed to play with this contrast and light, either to frighten and herd its prey, or to better camouflage itself. One detailed study on fin whale behaviour compared to that of other rorqual species with no asymmetry did not allow either of these assumptions to be corroborated. This asymmetry might constitute an original trait of the fin whale, not offering any benefit in particular.

On the surface

Breathing sequences can comprise 5 to 10 blows. When a fin whale breaches – which is rare – its body lands on its belly or flank with a loud splash. It generally doesn’t show its tail when diving, a flexion movement of its supple body being sufficient to nosedive to the ocean depths.

Diving

The fin whale shows a marked preference for shallow coastal waters (100-200 m deep) and rugged seabeds. It dives to various depths (from just below the surface to up to 230 m), with patterns linked to various activities (diurnal and nocturnal, travel, rest, exploration, feeding).

Social

They are observed alone, in pairs or in temporary groups the size of which varies from 3 to over 20 individuals. The presence of food and tidal cycles influence their dispersion and grouping. A detailed study conducted from 1994 to 1996 on their behaviour in the Estuary showed that they formed tight groups at high tide in the tide rips, swimming in a synchronized and dynamic manner. At low tide, they were rather dispersed and relaxed.

Vocalization

The sounds emitted by fin whales are in the low-frequency range (below 120 Hz). Their repertoire is dominated by short pulsing sounds of decreasing frequency (23 Hz to 18 Hz), singular or emitted in sequence. Produced primarily in winter, these sequences may be used for mating rituals. The highest-frequency sounds seem to be used for short-distance communication. According to one study, very low-frequency pulsing sounds appear to be used for echolocation as well.

Reproduction

Males reach sexual maturity between 8 and 12 years of age and females, between the ages of 6 and 10. Mating takes place between December and January. Gestation lasts between 11 and 12 months. Calves are born between November and January. Nursing lasts 6 to 7 months. Newborns measure on average 6.4 m and weigh 1.9 t. Females can give birth every 3 years.

About scientific research

Since 1986, the GREMM has been managing the catalogue of fin whales photo-ID’d in the Estuary (around 100 individuals), which, just like a family photo album, makes it possible to track the lives of individuals the likes of Capitaine Crochet, Triangle, Caïman, Zipper, etc. The catalogue compiled by MICS is composed of 450 individuals identified in the Gulf since 1980.

In the news

Find the latest news about the fin whale.