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Balaenoptera acutorostrata
common minke whale


By Bridget Fahey

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Cetacea
Family: Balaenopteridae
Genus: Balaenoptera
Species: Balaenoptera acutorostrata

Geographic Range

Minke whales have a worldwide distribution, appearing in all oceans and some adjoining seas. Cooler regions seem to be preferred over tropical regions.

Biogeographic Regions
arctic ocean (Native ); indian ocean (Native ); atlantic ocean (Native ); pacific ocean (Native )

Habitat

Although not considered "coastal", these baleen whales rarely venture farther than 169 km from land. They also commonly enter estuaries, bays, fjords, and lagoons. They are also know to move farther into polar ice fields than other rorqual species.

Aquatic Biomes
coastal

Physical Description

Range mass
6000 to 9000 kg
(13215.86 to 19823.79 lb)

Minkes are the smallest of the finback whales, growing to a maximum of 10.2 meters long. Females are larger than males, occasionally growing to a maximum of 10,000 kg. Coloration is dark above with a white underbelly. The head is pointed and bulletlike, with a relatively small rostrum. Baleen plates number around 300, are yellowish in color, and occasionally assymetrical in pattern. There are between 50-70 ventral grooves. A broad white band trims the dorsal side of flippers. The tail extends into two long tips. The dorsal fin is high and curved back.

Reproduction

Breeding interval
Females are thought to have young every other year.

Breeding season
The breeding period lasts from December to May in the Atlantic and year round in the Pacific

Average number of offspring
1

Average number of offspring
1
[External Source: AnAge]

Range gestation period
10 to 11 months

Average birth mass
320000 g
(11277.53 oz)
[External Source: AnAge]

Average age at sexual or reproductive maturity (female)
6 years

Average age at sexual or reproductive maturity (female)
Sex: female

2740 days
[External Source: AnAge]

Average age at sexual or reproductive maturity (male)
6 years

Average age at sexual or reproductive maturity (male)
Sex: male

2740 days
[External Source: AnAge]

Only one young is born at a time. Gestation lasts for 10 to 11 months. Weight at birth is 450 kg. The young are weaned at 5 months, but they do not become sexually mature for 6 years. Females are thought to have young every other year. The breeding period is long--from December to May in the Atlantic and year round in the Pacific. Peak months for births are December and June. Growth stops at about 18 years for females and 20 years for males.

Key Reproductive Features
iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Lifespan/Longevity

Average lifespan
Status: wild

45.0 years
[External Source: Max Planck Institute for Demographic Research]

Average lifespan
Status: wild

47.0 years
[External Source: Max Planck Institute for Demographic Research]

Average lifespan
Status: wild

50.0 years
[External Source: Max Planck Institute for Demographic Research]

Behavior

Minke whales travel either singly or in small groups (2-4), although they can be found in large aggregations in the hundreds where krill is abundant. They are thought to be curious, approaching ships and wharfs which is not typical of its family. They are also highly acrobatic, able to leap completely out of the water like a dolphin. Minkes are fast swimmers. Some populations are migratory--both southern and northern populations often spend winter in tropical waters, although these are actually at different times of year as a result of seasonal differences in their homelands.

Key Behaviors
natatorial ; migratory ; solitary ; social

Food Habits

A baleen whale, this species feeds primarily on krill and some small fish. There are regional differences in the diet. Minkes eat krill almost exclusively in the Antarctic, but they are more omnivorous in the northern hemisphere, taking as food squid and small vertebrates such as cod, herring, and sardines.

Primary Diet
carnivore (Eats non-insect arthropods)

Animal Foods
fish; mollusks; aquatic crustaceans

Foraging Behavior
filter-feeding

Economic Importance for Humans: Positive

Minke whales have been hunted by people for products such as meat, oil, and baleen since the Middle Ages. Regardless, it has never been of large commercial importance until other whale species were overhunted. Annual kill peaked in 1976 with 12,398 individuals, but now is down to < 1,000. These are taken primarily by indigenous peoples for food, or by scientists for research.

Economic Importance for Humans: Negative

None.

Conservation Status

IUCN Red List of Threatened Species [Link]
Least Concern
More Information

The global population is estimated at over 300,000 individuals, and there seems to be no cause for concern, since this species is not commonly hunted anymore. Many populations are on appendix 1 of CITES. Numbers have also been on the rise since the early 1900's because close competitors (other rorqual species) have been overhunted.

Other Comments

A second form of minke whale called the dwarf minke has been found off Australia/ New Zealand/ South Africa. There is debate as to whether this is a subspecies of B. acutorostrata or a different species altogether.

For More Information

Find Balaenoptera acutorostrata information at

Contributors

Bridget Fahey (author), University of Michigan.

References

Nowak, R.M. Walker's Mammals of the World, 5th Edition. Johns Hopkins University Press.

Grizemek's Encyclopedia of Mammals. McGraw-Hill Publishing Co.

To cite this page: Fahey, B. 1999. "Balaenoptera acutorostrata" (On-line), Animal Diversity Web. Accessed May 16, 2012 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Balaenoptera_acutorostrata.html

Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

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