Common minke whale
| Common minke whale[1] | |
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| Species: | B. acutorostrata
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| Balaenoptera acutorostrata Lacepede, 1804
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| Common minke whale range | |
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The common minke whale or northern minke whale, (Balaenoptera acutorostrata), is a species of minke whale within the suborder of baleen whales.
Taxonomy
Otto Fabricius, in his Fauna Groenlandica (1780), was the first to describe the minke, noting its small size and white baleen. He unfortunately described it under the name Balaena rostrata, which was already preoccupied by a beaked whale. In 1804, Baron de Lacepede named it Balaenoptera acuto-rostrata, basing his description partly on the stranding of a juvenile near Cherbourg, France in 1791.[3] There are several forms of common minke whale, including Scammon's minke whale (B. a. scammoni) from the North Pacific and the dwarf minke whale, from the Southern Hemisphere.[3]
Until recently, all minke whales were considered a single species. However, the common minke whale was recognized as a separate species from the Antarctic minke whale based on mitochondrial DNA testing.[4] This testing also confirmed that the Antarctic minke whale is the closest relative of the common minke whale, thus confirming the validity of the minke whale clade.[4]
Description
The common minke whale is the smallest of the rorquals, and one of the smallest baleen whales (second smallest only to the Pygmy Right Whale). At sexual maturity, Northern Hemisphere males average about 6.9 m (22.5 ft) and females 7.3 m (24 ft). In the North Atlantic, the average size at physical maturity is 8 m (26 ft) for males and 8.5 m (28 ft) for females, while maximum lengths are 8.8 m (29 ft) and 9.1 m (30 ft), respectively. At birth they are 2.6-2.8 m (8.5-9 ft) in length. For the dwarf form, the longest reported lengths are 7.62 m (25 ft) for males and 7.77 (25.5 ft) for females.
The back is dark grey and the belly white. All forms have a pale chevron above the flippers or behind the head. All forms also have a white or light marking on each flipper. On the dwarf form the white marking covers most of the flipper. On the northern forms, there is a distinct white band running horizontally through the middle of each flipper.[5]
The common minke whale differs from the Antarctic variety in several aspects. The common species is slightly smaller than the Antarctic, which has much less white marking on the flippers. There are also less distinctive differences in body coloration and shape.[5]
Distribution
Common minke whales have a disjointed distribution. In the North Atlantic, they occur as far north as Baffin Bay, Svalbard, Franz Josef Land, and Novaya Zemlya and as far south as 40° N (New Jersey) and the Hebrides and central North Sea during summer. They occur year-round off the Canary Islands. There are occasional sightings and strandings off Spain and Portugal, western Sahara, Mauritania, and Senegal. It is rare off the Azores and a vagrant in the Mediterranean Sea, with a single record in the Black Sea. During the winter it has been recorded off Bermuda, the Bahamas, the Antilles, and the east coast of the United States south of 40° N. In the western North Pacific, they range from the East China Sea, Yellow Sea and and Sea of Japan in the south to the Sea of Okhotsk and Bering and Chukchi Seas in the north. In the eastern North Pacific, they occur in the Gulf of Alaska south along the entire west coast of North America down to Baja California and into the Gulf of California. During winter, they've been acoustically recorded mainly between 15° and 35° N in the eastern and central North Pacific. The dwarf form occurs as far south as 65° S during summer, but was mainly caught between 55 and 62° S.[5] It has also been recorded off most of the South Atlantic coast of South America, in the Beagle Channel, off South Africa, Australia, New Zealand, New Caledonia, and as far north as 2° S (northern Brazil).
Feeding
Common minke whales have a diverse diet, feeding on various species of fish and crustaceans. In the North Atlantic, they prey on sand lance, sand eel, salmon, capelin, mackerel, cod, whiting, sprat, wolffish, dogfish, pollack, haddock, herring, euphausiids, and copepods. In the North Pacific, they mainly eat euphausiids, Japanese anchovy, Pacific saury, and walleye pollack. In the Southern Ocean, dwarf minkes feed mainly on myctophid fishes.[6]
Whaling
Whaling was mentioned in Norwegian written sources as early as the year 800 and hunting common minke whales with harpoons was common in the 11th century[citation needed].
By the end of the 1930s they were the target of coastal whaling from countries including Brazil, Canada, China, Greenland, Japan, Korea and Norway. Hunting continued apace until the general moratorium on whaling was introduced in 1986.
Following the moratorium, most hunting of common minke whales ceased. Japan and more recently Iceland (in August 2003) have continued hunting for minkes on scientific grounds, which have been criticised by many environmental organisations[7] as being a cover for commercial whaling. Both countries have the long-term goal of resuming open commercial whaling.[citation needed] Although Norway initially followed the moratorium, they placed an objection to it with the IWC and resumed commercial hunting in 1993. Norwegian whalers caught 639 in 2005. The quota for 2006 was set at 1052 animals, from which a catch of 546 was taken.[8]
Common minke whale-watching
Due to their relative abundance common minke whales are often the focus of whale-watching cruises setting sail from, for instance, the Isle of Mull in Scotland, County Cork in Ireland and Húsavík in Iceland. Common minke whales are frequently inquisitive and will indulge in "human-watching". In contrast to the spectacularly acrobatic humpback whale, minkes do not raise their fluke out of the water when diving and are less likely to breach. Minkes can stay submerged for as long as twenty minutes.[citation needed]
Conservation status
The common minke whale is considered "Least Concern" on the IUCN red list.[2] In addition, the species is covered by the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU) and the Agreement on the Conservation of Cetaceans in the Black Sea Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS)
See also
References
 | This article needs additional citations for verification. (December 2009) |
- ^ Mead, J. G.; Brownell, R. L. Jr. (2005). "Order Cetacea". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 723–743. ISBN 978-0-8018-8221-0. OCLC 62265494.
- ^ a b Template:IUCN2008
- ^ a b "Mammal Species of the World". Retrieved 2007-07-13.
- ^ a b "Cetacean mitochondrial DNA control region: sequences of all extant baleen whales and two sperm whale species". Retrieved 2007-07-13.
- ^ a b c Cite error: The named reference
princetonwas invoked but never defined (see the help page). - ^ Perrin, W. F., Bernd G. Würsig, and J. G. M. Thewissen. 2009. Encyclopedia of Marine Mammals. Amsterdam: Elsevier/Academic Press.
- ^ Help Us Stop Iceland's Whale Hunt!
- ^ Tok bare halve hvalkvoten - lofotposten.no
External links
- Smithsonian Institution - North American Mammals: Balaenoptera acutorostrata
- Official webpage of the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region
- Official website of the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area