Northern Minke Whale – Balaenoptera acutorostrata
The Northern Minke Whale, also known as Common Minke Whale, belongs to the family of the rorquals and is therefore part of the infraorder of the whales (Cetaceans). Balaenoptera acutorostrata was first described by Lacépède in 1804.
Description, Anatomy & Characteristics
The Northern Minke Whale reaches a maximum length of 10m, with females becoming about half a meter longer than males.
Its body is slender and elongated. While the back is dark grey or dark brown to black, the sides dark blue, the belly is white. The transition from dark to light is uneven and blurred. On the dark flippers is a light spot.
Since Balaenoptera acutorostrata belongs to the baleen whales, it has no teeth. Instead there are about 300 yellowish baleen in its upper jaw.
The fluke is very small compared to the body, sickle-shaped and sits on the back third of the body.
Habitat, Distribution & Occurrence
As its name suggests, Balaenoptera acutorostrata occurs in the northern hemisphere. It is mainly found in the North Atlantic and North Pacific. It can be observed on the high seas as well as close to the coast. In addition, Northern Minke Whale penetrates, contrary to some other species, into fjords, estuaries and bays. It is also said to visit the Mediterranean Sea from time to time and in 2006 there was even a sighting in the Black Sea.
There is said to be a sedentary population around the Canary Islands. Other populations usually migrate northwards during the summer months, while in winter they move further south. However, these migrations are irregular. It is interesting to note that males, females and animals of different ages travel separately. Males advance further north and females usually travel closer to the coasts.
Feeding & Biology
Balaenoptera acutorostrata lives solitary or in groups of up to 3 animals, more rarely up to 15 animals. At rich feeding-grounds, there can be gatherings of up to 400 individuals.
The Northern Minke Whale feeds mainly on krill, but small schooling fish are also on the menu.
In addition, they are fast swimmers and can jump completely out of the water like dolphins. In contrast to many other rorquals, they are curious and approach boats.
Reproduction & Development
Balaenoptera acutorostrata has a long reproductive season that lasts from December to June.
The gestation period is between 10 and 11 months. At birth a calf weighs up to 450kg and is almost 3.5m long. The birth takes place predominantly in warm waters.
It is assumed that females can give birth annually.
The northern minke whale becomes sexually mature between 3 and 8 years. Its life expectancy is estimated at about 50 years.