Minke whale (pron.: /ˈmɪnki/), or lesser rorqual, is a name given to two species of marine mammal belonging to a clade^[1] within the suborder of baleen whales. The minke whale was given its official designation^[2] by Lacepède in 1804,^[3] who described a juvenile specimen of Balænoptera acuto-rostrata.^[4] The name is a partial translation of Norwegian minkehval, possibly after a Norwegian whaler named Meincke, who mistook a northern minke whale for a blue whale.^[5]

Taxonomy

Most modern classifications split the minke whale into two species;

• Common minke whale or northern minke whale (Balaenoptera acutorostrata), and
• Antarctic minke whale or southern minke whale (Balaenoptera bonaerensis).^[6]

Taxonomists further categorize the common minke whale into two or three subspecies; the North Atlantic minke whale, the North Pacific minke whale and dwarf minke whale. All minke whales are part of the rorquals, a family that includes the humpback whale, the fin whale, the Bryde's whale, the sei whale and the blue whale.

The junior synonyms for B. acutorostrata are B. davidsoni (Cope 1872), B. minimia (Rapp, 1837) and B. rostrata (Fabricius, 1780). There is one synonym for B. bonaerensis - B. huttoni (Gray 1874).

Writing in his 1998 classification, Rice recognized two of the subspecies of the common minke whale - B. a. scammoni (Scammon's minke whale) and a further (taxonomically) unnamed subspecies found in the Southern Hemisphere to which he gave the common name the dwarf minke whale (first described by Best, 1986).

On at least one occasion, an Antarctic minke whale has been confirmed migrating to the Arctic.^[7][8] In addition, at least one wild hybrid between a common minke whale and an Antarctic minke whale has been confirmed.^[7][8]

Description

Minke whale skeleton, Museum Koenig, University of Bonn.

The minke whales are the second smallest baleen whale; only the pygmy right whale is smaller. Upon reaching sexual maturity (6–8 years of age), males measure an average of 6.9 m (23 ft) and females 7.4 m (24 ft) in length, respectively. Reported maximum lengths vary from 9.1 to 10.7 m (30 to 35 ft) for females and 8.8 to 9.8 m (29 to 32 ft) for males. Both sexes typically weigh 4–5 t (3.9–4.9 long tons; 4.4–5.5 short tons) at sexual maturity, and the maximum weight may be as much as 10 t (9.8 long tons; 11 short tons).

The minke whale is a black/gray/purple color. Common minke whales (Northern Hemisphere variety) are distinguished from other whales by a white band on each flipper. The body is usually black or dark-gray above and white underneath. Minke whales have between 240 and 360 baleen plates on each side of their mouths. Most of the length of the back, including dorsal fin and blowholes, appears at once when the whale surfaces to breathe.

Minke whales typically live for 30–50 years; in some cases they may live for up to 60 years.

The brains of minke whales have around 12.8 billion neocortical neurons and 98.2 billion neocortical glia.^[9]

Behavior

Multimedia relating to the minke whale Note that whale calls have been sped up to 10x their original speed.

An Atlantic minke whale Problems listening to this file? See media help.

The whale breathes three to five times at short intervals before 'deep-diving' for two to 20 minutes. Deep dives are preceded by a pronounced arching of the back. The maximum swimming speed of minkes has been estimated at 38 km/h (24 mph).

Reproduction

The gestation period for minke whales is 10 months, and calves measure 2.4 to 2.8 m (7.9 to 9.2 ft) at birth. The newborns nurse for five to possible 10 months. Breeding peaks during the summer months. Calving is thought to occur every two years.^[10]

Population and conservation status

The IUCN Red List labels the common minke whale as Least Concern.^[11] The Antarctic minke whale is listed as Data Deficient.^[12]

COSEWIC puts both species in the Not At Risk category [1]. NatureServe lists them as G5 which means the species is secure on global range [2].

In 2012, the Scientific Committee of the International Whaling Commission agreed upon a population estimate of 515,000 for the Antarctic minke stock. ^[13] The Scientific Committee acknowledged that this estimate is subject to a negative bias because some minke whales would have been outside the surveyable ice edge boundaries.

Whaling

Norwegian minke whale quotas (blue line, 1994-2006) and catches (red line, 1946-2005) in numbers (From Norwegian official statistics)

Whaling was mentioned in Norwegian written sources as early as the year 800, and hunting minke whales with harpoons was common in the 11th century^{[citation needed]}. In the 19th century, they were considered too small to chase, and received their name from a young Norwegian whale-spotter in the crew of Svend Foyn, who harpoooned one, mistaking it for a blue whale and was derided for it.^[14]

By the end of the 1930s, they were the target of coastal whaling by Brazil, Canada, China, Greenland, Japan, Korea, Norway, and South Africa. Minke whales were not then regularly hunted by the large-scale whaling operations in the Southern Ocean because of their relatively small size. However, by the early 1970s, following the overhunting of larger whales such as the sei, fin, and blue whales, minkes became a more attractive target of whalers. By 1979, the minke was the only whale caught by Southern Ocean fleets. Hunting continued apace until the general moratorium on whaling began in 1986.

Following the moratorium, most hunting of minke whales ceased. Japan continued catching whales under the special research permit clause in the IWC convention, though in significantly smaller numbers. The stated purpose of the research is to establish data to support a case for the resumption of sustainable commercial whaling. Environmental organizations and several governments contend that research whaling is simply a cover for commercial whaling. The 2006 catch by Japanese whalers included 505 Antarctic minke whales.

Although Norway initially followed the moratorium, they had placed an objection to it with the IWC and resumed a commercial hunt in 1993. The quota for 2006 was set at 1,052 animals, but only 546 were taken.^[15] The quota for 2011 is set at 1286.^[16] In August 2003, Iceland announced it would start research catches to estimate whether the stocks around the island could sustain hunting. Three years later, in 2006, Iceland resumed commercial whaling.

A 2007 analysis of DNA fingerprinting of whale meat estimated South Korean fishermen caught 827 minke between 1999 and 2003.^[17]

Whale Watching

Common minke whale breaching in the St. Lawrence River near Tadoussac, Quebec

Minke whale in the Ross Sea

Due to their relative abundance, 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, and tours taken on the east coast of Canada. In contrast to humpback whales, minkes do not raise their flukes out of the water when diving and are less likely to breach (jump clear of the sea surface). This, combined with the fact that minkes can stay submerged for as long as 20 minutes, has led some whale-watchers to label them 'stinky minkes'.^[18]

In the northern Great Barrier Reef (Australia), a swim-with-whales tourism industry has developed based on the June/July migration of dwarf minke whales. A limited number of reef tourism operators (based in Port Douglas and Cairns) have been granted permits by the Great Barrier Reef Marine Park Authority to conduct these swims, given strict adherence to a code of practice, and that operators report details of all sightings as part of a monitoring program. Scientists from James Cook University and the Museum of Tropical Queensland have worked closely with participating operators and the Authority, researching tourism impacts and implementing management protocols to ensure these interactions are ecologically sustainable.

Minke whales are also occasionally sighted in Pacific waters, in and around the San Juan Islands of Washington State.

References

Cetaceans portal

General references

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

Skeleton of the Common minke whale.

A minke whale in the Gulf of St. Lawrence, showing the blowholes and dorsal fin at the same time

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

View of a common minke whale underwater, showing the diagnostic white flipper band

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 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

Norwegian minke whale quotas (blue line, 1994-2006) and catches (red line, 1946.2005) in numbers (from Norwegian official statistics)

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

Common minke whale breaching in the St. Lawrence River near Tadoussac, Quebec

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

	Cetaceans portal
	Marine life portal

• List of whale and dolphin species
• Marine biology
• List of whale vocalizations

References

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2009)