Length: 7 – 10 m (23 – 33’)
Weight: 6 – 8 tons
Population size in Canada: unknown
Population size in World: unknown, thought to over 1 million animals
Conservation status in Canada: Not at Risk (COSEWIC)
Conservation status in World: Lower risk: near threatened (IUCN)

Classification

Latin Name: Balaenoptera acutorostrata
Other Names: lesser rorqual, little piked whale
Suborder: Mysticete (Baleen Whale)
Family: Balaenopteridae

Field Identification
  • up to 10 m
  • medium size, with a slender body shape
  • narrow and extremely pointed head
  • two blowholes
  • yellowish-white baleen, ~ 20-30 cm in length
  • tall falcate dorsal fin
  • white band on pectoral fins
  • black on top, grey on sides, white belly
  • ventral grooves ending before navel around tips of flippers
  • low, thin, whispy blow is difficult to see
  • arches body on diving but does not show flukes
  • usually single or in groups of 2-3, may aggregate in larger groups at good feeding areas
Description

The smallest baleen whale in the northern hemisphere, the minke whale is dark grey to nearly black in colour with lighter chevrons on the top and flanks, and a  white belly. A distinct white patch runs across the pectoral fins. Minkes have a relatively slender body and a very sharply pointed head that appears v-shaped when viewed from above. They have a tall, falcate dorsal fin that is located relatively far forward and appears simultaneously with the blowholes when they surface.  The blow is inconspicuous except when backlit by the sun or on cold days.

Life History

Breeding and calving is likely correlated with seasonal migrations.  Migration appears to be segregated according to age and sex.  Gestation lasts 10 months, and lactation is as long as 45 months, and females may be capable of annual reproduction. Minke whales are thought to live up to at least 50 years, and males become sexually mature at 7 years of age, while females reach sexual maturity earlier, at 6 years of age.

Distribution

Minke whales are among the most widely distributed of all the baleen whales. In the north Atlantic, the minke whale ranges from Arctic waters to the Caribbean and the Straits of Gibraltar. They are commonly seen in coastal waters off the Maritime Provinces. The migrations of this species are not well understood, although they likely have a seasonal migration to warmer waters in the winter.  However, they are occasionally seen off Nova Scotia during the winter.

Diet

Minke whales belong to a group of baleen whales known as rorquals, which use their baleen to filter food from large mouthfuls of water.  Minke whales eat a wide variety of prey, although they can specialize both temporally and geographically. North Atlantic minke whales are known to feed on sand lance, salmon, mackerel, capelin, haddock, euphausiids (krill) and a variety of other prey items.

Behaviour

Minke whales are usually alone or in small groups. Their small size, inconspicuous blow and quick surfacings make them difficult to observe, however, they are sometimes curious and may approach boats. Minke whales are not considered to be acrobatic, however, they will occasionally breach. When diving, minke whales arch their back but don’t raise their flukes.

Population size

Minke whales are thought to be abundant throughout their entire range. Population centres are found in the southern hemisphere, north Atlantic and north Pacific. While most minke whale populations are in better condition than most populations of other large whales, questions remain about the status of some populations and the effects of continued whaling. In 1989, the International Whaling Commission estimated the southern hemisphere population to be 761,000. The North Atlantic and North Pacific populations were estimated to be considerably smaller with only 174,000 in 2001 and 25,000 in 1990, respectively. To understand current population sizes, these estimates need to be updated.

Threats

The current state of global minke whale populations is unknown. In the North Atlantic, Norway has a commercial whaling industry for minke whales (Japan does so in the Pacific, for sperm and Bryde’s whales as well). Like other species, minke whales are also threatened by chemical and noise pollution, habitat degradation, entanglement in fishing gear, vessel strikes and harassment.