Common Minke Whale

## Description

The common minke whale or northern minke whale (Balaenoptera acutorostrata ) is a species of minke whale within the suborder of baleen whales.

It is the smallest species of the rorquals and the second smallest species of baleen whale. Although first ignored by whalers due to its small size and low oil yield, it began to be exploited by various countries beginning in the early 20th century. As other species declined larger numbers of common minke whales were caught, largely for their meat. It is now one of the primary targets of the whaling industry. There is a dwarf form in the Southern Hemisphere.

This species is known in the fossil record from the Pliocene epoch to the Quaternary period (age range: 3.6 million years ago to present day).

## Appearance

Common minke whales are one of the smallest baleen whales (second smallest only to the Pygmy right whale). Females are larger than males. They have a dark gray back and clean white underbelly. The jaw is dark gray on both sides. Common minke whales have about 230-360 pairs of creamy white baleen plates with a fine white fringe. They possess 50-70 thin ventral pleats, which only extend about 47 percent of the body length. The tail of these whales extends into two long tips and the dorsal fin is high and curved back.

## Distribution

Common minke whales are found in all oceans and some adjoining seas. The migration patterns of these whales are poorly known. They occur in the North Atlantic, the North Pacific, and the Southern Hemisphere. Common minke whales prefer cooler regions. They occur in both coastal and offshore waters. They also often enter bays, estuaries, lagoons and fjords.

## Behavior

Common minke whales are usually seen singly or in small groups of 2-4 individuals; however, where food is abundant they can be seen in large aggregations. These whales are curious creatures. They often approach ships and wharfs which is not typical for whales of their family. They are also highly acrobatic. They can leap completely out of the water like dolphins. Common minke whales are fast swimmers. Some of their populations are migratory. Both southern and northern populations often spend winter in tropical waters, although at different times of the year. This happens because of seasonal differences in their homelands.

## Diet

Like all baleens, Common minke whales are carnivorous. They feed on krill and some small fish. Their diet also includes pelagic crustaceans and cephalopods and varies by region, season, and year.

## Reproduction

Little is known about the reproductive behavior of Common minke whales. Females are known to be promiscuous, suggesting that these minke whales exhibit polygynandrous (promiscuous) mating system. In the Atlantic, breeding takes place in December-May and in the Pacific, it lasts year round. Females have young every other year. Gestation period lasts 10 months after which a single calf is born. The calf is weaned after a period of 6 months. Common minke whales become reproductively mature at about 6-8 years of age for females and about 6-7 years for males.

## Population

### Population threats

Scientific and commercial whaling are major threats for the Common minke whale. They are cought largely for their meat. It is now one of the primary targets of the whaling industry. Minke whales are occasionally caught in fishing gear of various types, including set nets, fish pots, gillnets, trap nets, trawls, longlines, and seines. Habitat shifting and alteration are another threats to these whales.

### Population number

According to IUCN, there is no overall population estimate available for the Common minke whale. However, there are estimates of its populations in the following area: North Atlantic - about 182,000 individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers remain stable.