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Commission
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Whales
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Conservation & Management
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Scientific Research
Scientific Committee 2016 - SC66b
The 2016 meeting of the IWC Scientific Committee will be held at the Hotel Golf, Bled, Slovenia from 4th June to 20th June.
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Scientific Research
In this section
Whale Watching
Details and characteristics of the 13 great whales, including the life histories of Baleen and Sperm Whales
On this page
Great Whales Table with all 13 Great Whales listed Species Brief details of individual species Sperm Whales Summary of the life history of baleen whales Baleen Whales Summary of the life history of the sperm whale The Great Whales
The first twelve of these are baleen (whalebone) whales, filter feeders with baleen plates instead of teeth and the sperm whale is the largest toothed whale. Click on the link to see more detailed information on each species.
- Bowhead (or Greenland right whale)
Balaena mysticetus - North Atlantic right whale
Eubalaena glacialis - North Pacific right whale
Eubalaena japonica - Southern right whale
Eubalaena australis - Gray whale
Eschrichtius robustus - Blue whale
Balaenoptera musculus - Fin whale
Balaenoptera physalus
- Sei whale
Balaenoptera borealis - Bryde's whale
Balaenoptera edeni - Common minke whale
Balaenoptera acutorostrata - Antarctic minke whale
Balaenoptera bonaerensis - Humpback whale
Megaptera novaeangliae - Sperm whale
Physeter macrocephalus
Bowhead whale
Average length (m): 14-15 (females are larger) Average weight (tonnes): 50-60 Conservation: Heavily reduced by whaling up to the late 19th century. Only one population is in a healthy state, the Bering-Chukchi-Beaufort Seas stock. Distribution: Circumpolar in high latitudes of the Northern Hemisphere Migration: Northwards in spring and southwards in autumn Primary prey: Copepods and krill Feeding: Skim feeder 
North Atlantic right whale
Average length (m): 13.5-17 (females are larger) Average weight (tonnes): 40-80 Conservation: Heavily reduced by whaling up to the late 19th century, the largest stock remaining is in the western North Atlantic and numbers only about 300 animals. This is one of the most endangered species of great whale. Distribution: Western NA ranges from Nova Scotia and the Bay of Fundy in summer, Cape Cod in spring and breeding grounds near Florida in winter; eastern NA historical records show range from the Azores as far north as Greenland, Spitsbergen and Norway Migration: Between high-latitude feeding grounds in summer and lower-latitude breeding grounds in winter Primary prey: Copepods and occasionally krill Feeding: Skim feeder 
North Pacific right whale
Average length (m): 13.5-18 (females are larger) Average weight (tonnes): 40-80 Conservation: Heavily reduced by whaling up to the late 19th century. This is one of the most endangered species of great whale. Distribution: Records exist as far south a central Baja California and north to the Gulf of Alaska and Bering Sea in the eastern NP and in the west, range is from the Okhotsk Sea and Kuril Islands in the north, although no calving grounds have been located in the south Migration: Between high-latitude feeding grounds in summer and lower-latitude breeding grounds in winter Primary prey: Copepods and occasionally krill Feeding: Skim feeder 
Southern right whale
Average length (m): 13.5-16 (females are larger) Average weight (tonnes): 40-80 Conservation: Heavily reduced by whaling up to the late 19th century, but showing encouraging signs of increase in several regions, notably off Australia, Argentina and South Africa. Distribution: Circumpolar between 20°S and 55°S, spending the austral winter off the coasts of South America, South Africa and Australasia, and the austral summer around Antarctica and the Southern Ocean Migration: Between high-latitude feeding grounds in summer and lower-latitude breeding grounds in winter Primary prey: Copepods and occasionally krill Feeding: Skim feeder 
Gray whale
Average length (m): 13-14.1 (females are larger) Average weight (tonnes): 14-35 Conservation: Heavily reduced by whaling up to the late 19th century. The eastern stock has returned to close to its original population size (ca 20,000) whereas the western stock numbers less than 100 animals and is one of the most endangered populations of great whale. Distribution: The North Pacific Ocean – the small western population ranges from Korea in the south to the Okhotsk Sea in the north, and the large eastern population from Mexico in the south to the Bering, Chukchi and Beaufort Sea in the north Migration: Between high-latitude feeding grounds in summer and lower-latitude breeding grounds in winter Primary prey: Benthic amphipods Feeding: Bottom feeder 
Blue whale
Average length (m): 25-26.2 (females are larger) Average weight (tonnes): 100-120 Conservation: The primary target species of modern whaling, it was reduced in all waters to very low levels until protected in the mid-1960s. Showing some signs of recovery in the Southern Hemisphere and North Atlantic but generally remains at very low levels. Distribution: Worldwide, from the equator to the polar regions in both hemispheres Migration: Movements to polar waters for feeding in the summer and back to low latitudes for breeding in the winter Primary prey: Krill Feeding: Lunging and gulping 
Fin whale
Average length (m): Southern Hemisphere: 21-22.3 (females are larger)
Northern Hemisphere: 19-20 (females are larger)Average weight (tonnes): 45-75 Conservation: A primary target for modern whaling. Heavily reduced, particularly in the North Pacific and Southern Hemisphere. Evidence of recovery in the North Atlantic and parts of the Southern Hemisphere. Distribution: Worldwide, ranging from temperate to polar waters and less commonly in the tropics Migration: Between high-latitude feeding grounds in summer and lower-latitude breeding grounds in winter – some evidence to suggest that some populations may shift in winter to occupy the summer habitats of others Primary prey: Krill and small schooling fish Feeding: Lunging and gulping 
Sei whale
Average length (m): Southern Hemisphere: 15-16 (females are larger)
Northern Hemisphere: 13.6-14.5 (females are larger)Average weight (tonnes): 20-25 Conservation: A target for modern whaling but not reduced as heavily as blue and fin whales. Distribution: Worldwide from subtropical or tropical waters to high latitudes of the sub-Arctic and sub-Antarctic Migration: Seasonal movements between high latitudes in summer to tropical waters in winter generally accepted for many populations Primary prey: Krill, small fish, squid and copepods Feeding: Gulping and skimming 
Bryde's whale
Average length (m): 13.7-14.5 (females are larger) Average weight (tonnes): 16-18.5 Conservation: A target for modern whaling but not reduced as heavily as blue and fin whales. Distribution: Worldwide in tropical to temperate waters, usually found below 35° latitude in both hemispheres Migration: Offshore form may make limited north-south seasonal movements Primary prey: Small schooling fish and sometimes krill Feeding: Lunging and gulping 
Common minke whale
Average length (m): 8-10 (females are larger) Average weight (tonnes): 9 Conservation: Has been hunted in the North Atlantic and North Pacific but remains abundant in many areas Distribution: North Atlantic and North Pacific, from tropical to polar waters. Dwarf form found in Southern Hemisphere. Migration: Northward movement from warmer waters in winter to colder waters in summer Primary prey: Small school fish and krill Feeding: Lunging and gulping 
Antarctic minke whale
Average length (m): 10-11 (females are larger) Average weight (tonnes): 9 Conservation: Has been hunted in the Antarctic and some more northerly waters (e.g. Brazil, South Africa) but remains abundant in most areas. Distribution: Circumpolar in the Southern Hemisphere, summering in waters around Antarctica and wintering between about 7° and 35°S Migration: Shifts in latitudinal abundance with season but poorly known Primary prey: Krill and sometimes schooling fish Feeding: Lunging and gulping 
Humpback whale
Average length (m): 12-14 (females are larger) Average weight (tonnes): 25-30 Conservation: Has been heavily exploited in the past but recovering in most areas. Distribution: Widely distributed, occurring seasonally in all oceans from the Arctic to the Antarctic Migration: Between mid- and high latitude summer feeding grounds to tropical or subtropical winter breeding and calving grounds Primary prey: Krill and small schooling fish Feeding: Lunging and gulping 
Sperm whale
Average length (m): female 11, male 15 Average weight (tonnes): female 20, male 45 Conservation: Has been heavily exploited in past by both ‘old’ and modern whaling but reasonably abundant in most areas Distribution: Worldwide, from the equator to polar regions Migration: Only adult males move into latitudes higher than 45° in both hemispheres to feed, although seasonal movements from higher to lower latitudes between summer and winter do occur in some segments of populations Primary prey: Squid, fish in some places Feeding: Mainly on or near the ocean bottom
BALEEN WHALES
The general pattern of life for the baleen whales is to breed in the temperate and warm equatorial waters in the winter months, and to feed in more polar waters during the summer (apart from the Bryde’s whale that does not migrate to the polar waters). Most species carry out long migrations each year between the breeding and feeding areas. Because the seasons are opposite in the Northern and Southern Hemispheres, whales in the two halves of the world do not mix.
Feeding
The baleen whales have several hundred elongated triangular baleen plates growing down on either side from the roof of their mouths. These plates are made of a horny material and not of bone, even though they are popularly called whalebone. The baleen plates are 1-3cm (1/2-1 inch) apart and fringed internally with fibres forming a sieve. The whale takes in a large mouthful of water containing the shrimps or other small crustaceans or fish on which it feeds. When the mouth is closed, the throat region tightened and the large tongue pushed up, the water is forced out between the baleen plates and the food is left trapped and can be swallowed. Some whales can also swim with their mouths open, straining out food continuously.
Most baleen whales feed for only four or five months a year when they are in polar seas which are particularly rich in food. A large whale will swallow two tons of food a day, and it builds up a store of energy in the form of a thick layer of blubber under the skin to last it through the rest of the year when it feeds very little.
Reproduction
The baleen whales migrate several thousand miles to their breeding grounds in the warm waters where they pair and mate. The females carry a single young for almost exactly a year. During this time they migrate to the summer polar feeding grounds and then return to calve in the warm water areas. The calf of a blue whale is about 7m (23ft) long at birth and weighs two and a half tons. It feeds on its mother's milk for seven months while the whales migrate to the feeding grounds where the calf is weaned and can fend for itself. By this time the blue whale calf has grown to a length of 16m (53ft) and a weight of 23 tons. The mother then has a five months long resting period in her breeding cycle, during which she migrates back to the warmer waters where she mates again, two years after the start of the previous pregnancy.
Hearing
Hearing is the most important sense for whales, which allows them to find their way around in the low light intensities which occur below the ocean surface. Whales make a wide range of sounds by which they echo-locate to find their food, detect all the other animals and physical features in their environment, and also communicate with each other. An important part of the hearing mechanism in some species of whales is a horny plug in the ear canal. This has particular acoustic conducting properties which gives the whale its acute sense of hearing.
Age
The earplug has a layered structure which is visible when the plug is bisected. It has been discovered that one growth layer is formed each year (rather like the rings in a tree-trunk), so that the age of the whale can be found by counting the number of layers. These counts show that fin whales may live for up to 90 years, so that they can have a life-span very similar to man.
The sperm whale differs in many respects from the baleen whales. In particular, like the small cetaceans, they do not have baleen plates in the mouth but have teeth (hence the scientific name of the suborder: Odontoceti). Male sperm whales grow much larger than the females, up to 18m (60ft) in length and 70 tons in weight compared to 11.5m (38ft) and 17 tons. The single young is carried for 14-15 months by the mother, the calf is then suckled for about two years and a resting period completes the normal four year breeding cycle. Sperm whales do not carry out the regular annual migrations between the warmer and colder seas characteristic of the baleen whales, although there are regular seasonal shifts of the sperm whale populations. The females, juveniles and small males swim about in nursery groups numbering 10, 20 or more animals and they remain in temperate waters all the year round. During the winter breeding season they are joined for a time by one or more large males. Medium sized males tend to swim together in groups of half a dozen in the temperate waters, but the biggest males are rather more solitary. It is only the big male sperm whales which penetrate into the polar seas.
Sperm whale diet consists mainly of squids, which are swallowed whole, and fish are also eaten in some areas of the world. A large male sperm whale will eat about one and a third tons of food a day, although a female only requires a quarter of this amount.
The teeth of the sperm whale can be used to find the age of the animal. They are composed largely of dentine, which is deposited in a series of annual layers. The teeth are sawn in half lengthways and etched with acid to help distinguish between the different layers. The layer counts show that sperm whales live for up to 60+ years.
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Conservation & Management
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Whales
