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Balaenoptera acutorostrata
Minke Whale [ + ]

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Balaenopteridae
Genus: Balaenoptera
species: acutorostrata
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Description & Behavior

Minke whale song

There are two species of minke whales: the minke whale, aka common or northern minke whale, Balaenoptera acutorostrata (Lacépède, 1804, acutorostrata means 'sharp snouted') and the Antarctic or southern minke whale, Balaenoptera bonaerensis (Burmeister, 1867).

Minkes are the smallest of the baleen whales with 50-70 throat grooves. It is a Rorqual whale (Family Balaenopteridae, the family that includes the: blue whale , Bryde's whale , fin whale , humpback whale , minke whale , and sei whale ) These long, slender whales are much more streamlined than other whales. They have a pointed snout that is distinctively triangular, narrow, and pointed (hence its nicknames "sharp-headed finner" and "little piked whale"), paired blowholes, and a broad, flat rostrum (upper part of the head). The throat grooves, in addition to streamlining the shape of the whale, allow the throat area (called the cavum vent-rale ) to expand tremendously during feeding.

Minkes are the most abundant baleen whale and have a characteristic white band on each flipper (this is absent on the southern minke whales), contrasting with its very dark gray top color, sometimes with pale trapezoidal stripes behind the flippers on the top. They have 2 blowholes, like all baleen whales.

Minke whales grow to be about 7.8- 9 m long, weighing about 5,400- 6,800 kg. Females are about 0.6 m longer than males, as with all baleen whales. The largest minke whale was about 10.5 m long weighing 8,600 kg.

Minke Whale, Balaenoptera acutorostrata

There are three subspecies of common or northern minke whales, B. acutorostrata :

1. North Atlantic minke whale, B. acutorostrata acutorostrata (Lacépède, 1804)
2. North Pacific or Scommon's minke whale, B. acutorostrata scammoni (Deméré, 1986)
3. dwarf-form or dwarf minke whale, B. acutorostrata subsp

Minke whales are stocky, having a layer of blubber several inches thick. They have 50-70 throat grooves, running from the chin to the mid-section. The minke whale has two long flippers (up to 1/8 of the body size), a small dorsal fin, and a series of small ridges along the its back near the flukes (tail).

Minke whales either travel singly or congregated in small pods of about 2-3 whales.

Minke whales can dive for up to 20-25 minutes, but usually make shorter dives, lasting about 10-12 minutes. Just before diving, minke whales arch their back to a great degree, but the flukes do not rise out of the water.

At rest, minke whales spout (breathe) about 5-6 times per minute. The spout of the minke whale is a very low, almost inconspicuous stream that rises up to 2 m above the water. Minke whales begin exhaling before they reach the surface, which minimizes the blow.

Minke whales makes very loud sounds, up to 152 decibels (as loud as a jet taking off). They make series (trains) of grunts, thuds, and raspy sounds, usually in the 100-200 Hertz range. These sounds may be used in communication with other minke whales and in echolocation.

World Range & Habitat

Minke whales live at the surface of the ocean in all but polar seas.

Minke whales normally swim 4.8- 25 kph, but can go up to 29- 34 kph in bursts when in danger. Feeding speeds are slower, about 1.6- 9.8 kph.

» GBIF occurrence data in Google Earth [ Tips ] | Ocean Biogeographic Information System (OBIS) (World Distribution) [about]

Feeding Behavior (Ecology)

Minke whales, Balaenoptera bonaerensis , (like all baleen whales) are seasonal feeders and carnivores. They sieve through the ocean water with their baleen. They filter out small polar plankton, krill, and small fish, even chasing schools of sardines, anchovies, cod, herring, and capelin. They have the same diet as blue whales .

The baleen plates in the minke whale's jaws have about 300 pairs of short, smooth baleen plates. The largest plates are less than 30 cm long and 13 cm wide. The fine textured baleen bristles are fringed and with white bristles.

Life History

Minke whale breeding occurs mostly in the late winter to early spring while near the surface and in warm waters. The gestation period is about 10 months and the calf is born near the surface of the warm, shallow waters. The newborn instinctively swims to the surface within 10 seconds for its first breath; it is helped by its mother, using her flippers. Within 30 minutes of its birth the baby whale can swim. The newborn calf is about 2.8 m long and weighs about 454 kg. The baby is nurtured with its mother's milk. The mother and calf may stay together for a year or longer. Minke whales reach puberty at 2 years of age.

Minke whales have a life expectancy of over 20 years.

It is estimated that there are about almost 800,000 minke whales worldwide.

Conservation Status/Additional Comments

The story of this whale's name illustrates its blighted history. Minke was an 18th-century Norwegian whaler, infamous for regularly breaking the rules concerning the sizes (and therefore species) of whales that he was permitted at that time to hunt. Soon all the small whales became known as "Minke's whales". Eventually, it was formally adopted as the name for this small species.

In fact, because they are such a small whale, the whaling industry generally ignored the minkes until quite recently. As the larger whales became more scarce (and gained protected status), so minke whales became more economically attractive. In the North Atlantic, from the 1920s, whaling for this species has been conducted along the coast of Norway. When whale populations dwindled in the late 1940s, the International Whaling Commission (IWC) was established to manage whale stocks. The IWC announced how many whales could be taken in any year, however, populations continued to decline. In 1985-1986 a worldwide moratorium on whaling was put in place, banning all whaling. Norway, however, "took out a reservation", meaning that they could continue by IWC rules to legally hunt North Atlantic minke whales and, in 1993 and 1994, they killed several hundred. This has caused great dismay in other countries, including the U.K., who have officially objected to this hunt. In UK waters it is illegal to intentionally kill, injure, capture or harass any species of whale or dolphin. However, there is little in international law that can be done about hunting, except control of exports which is covered by CITES (the Convention for International Trade in Endangered Species). This is important because the main consumers of whale meat are still the Japanese and, if Norway could legally export whale meat to Japan, this might further promote whaling.