Baleen Whales (Families Balaenidae, Balaenopteridae, and Neobalaenidae)
Southern right whale, Te Wae Wae Bay, Southland, July 1990. Photographer Andy Cox. Crown Copyright, Department of Conservation
Alan Baker, Suze Baird, and Taoho Patuawa
General Description
Baleen whales comprise a suborder of cetaceans, Mysticeti. Of the four families, six genera, and thirteen species, there are three families in New Zealand waters containing ten species in four genera. Baleen whales are characterised by baleen plates on each side of the upper jaw which act as a filter-feeding apparatus to trap small crustaceans and fish. The rorquals, of the family Balaenopteridae, have sleek bodies, free neck vertebrae, and pleats on the underside of the throat. This family includes the blue, fin, sei, Bryde's, Antarctic minke, and humpback whales. The family Balaenidae, right whales, is characterised by a rotund body form with fused neck vertebrae, no dorsal fin, no ventral pleats, and long, narrow baleen plates. The one species in New Zealand waters, principally in the subantarctic, is the southern right whale. The family Neobalaenidae includes a single species; the pygmy right whale.
Baleen whales include some of the biggest animals in the world. They range in size from about 6 m in the pygmy right whale to over 30 m in the blue whale, the largest of which was reported at about 180 tonnes. Baleen whales have a general life expectancy between 50 to over 70 years. Most species are highly migratory, returning to the same areas to breed. Migratory movements to feeding grounds are initiated by newly pregnant females who are the last to return to warmer waters to calve. The social organisation varies for each species, with whales often seen alone, in cow-calf pairs, or in small groups. Large groups of some species are present at feeding aggregations, and fin, sei, and blue whales may feed together.
The length, number, and form of the baleen plates reflect food preferences of different species. Baleen whales have several feeding methods. Rorquals use their ventral pleats to greatly extend their mouth opening to "gulp" large amounts of water containing krill, copepods, and small fish. Feeding in this manner, blue whales consume from three to eight tonnes of zooplankton daily during summer. Southern right whales feed by "skimming", which involves continuous straining of zooplankton as the animals swim at the surface. Sei whales use both feeding methods. Blue whales feed by "lunging" into schools of krill. Humpback whales forage cooperatively and may use a "bubble net" to concentrate and trap fish and other prey species.
Most baleen whales feed during summer in colder prey-rich waters and exist mainly on their fat reserves during winter months when they migrate to warmer waters to breed. Reproduction varies among the species, but generally, a female gives birth to a single calf every three to five years. Female minke whales can calve every one to two years. Gestation period is approximately 10 to 12 months and calves are typically weaned after six months to a year.
The pygmy right whale is poorly known in terms of its social structure, feeding, and mating behaviours. Limited observations at sea suggest they are usually solitary animals or in pairs, with few records of large aggregations.
Individuals of 77% of the world's baleen whale species occur seasonally within the New Zealand region. Southern right, Bryde's, and dwarf minke are the only baleen whales known to breed in New Zealand waters.
Status
The populations of several species of baleen whale were greatly reduced as a result of commercial whaling in the nineteenth and twentieth centuries and are making a slow recovery to former abundance levels. Of the baleen whales that occur within the New Zealand region, five species are listed as "endangered" or "vulnerable" under the IUCN threat classification system. Of those breeding in New Zealand waters, Bryde's whale is ranked as "nationally critical" and the southern right whale as "nationally endangered" by the Department of Conservation.
Key Locations
Blue, fin, sei, and humpback whales are cosmopolitan in their distribution; whereas southern right, dwarf minke, Antarctic minke, and pygmy right whales are restricted to the southern hemisphere. Bryde's and dwarf minke whales prefer the more temperate waters and are seen off the New Zealand coast in and north of the Bay of Plenty. A population of Bryde's whales is resident in the Hauraki Gulf and breeds there in summer. Other baleen whales are found at higher latitudes, particularly when feeding in summer in Antarctic waters, with Antarctic minke whales and sei whales distributed right to the ice edge. Southern right whales mate and calve during winter in sheltered harbours of the subantarctic Auckland Islands and Campbell Island. These whales once bred in large harbours around the New Zealand mainland. Other important areas for baleen whales include waters off Kaikoura, Cook Strait, and off the west coast of the South Island when baleen whales migrate between their feeding and breeding grounds (May-July and November-December).
Summary of Threats
Most baleen whales are now protected from human exploitation throughout their range and there are few current threats for baleen whales, though the continued "scientific whaling" in the Southern Ocean is considered a threat for some species. In areas of the Hauraki Gulf with relatively high ship-traffic, vessel strike and interference with whale movements may represent a threat. Entanglement with fishing gear, underwater sonar activity, and further development of the whale-watching tour industry may pose threats to individuals or induce modification of whale movement and behaviour. Other human-induced threats include exposure to marine pollutants, overfishing of prey species, and effects from climate change that may affect the location and abundance of food sources and degrade their habitats. Natural threats include parasitic infestation and predation by sharks, killer whales, and false killer whales.
Typical Habitats
Baleen whales are often associated with waters over the continental shelf and their migratory routes pass over ocean basins. Most species use sheltered waters to breed and may venture into harbours or inlets to calf.
State of Information
The knowledge of baleen whale biology and ecology is generally good. However some species, such as the southern right whale and pygmy right whale, have few studies that are able to describe their social structure, feeding, and breeding. Further taxonomic work is required to conclude the present debate over the number of baleen whale species, and more information is needed on abundance and migration paths of many species.
Significance for Maori
In Maori cosmology, all whales descended from Tangaroa. Maori described whales as "chiefly fish". In the migration legends, whales were used to guide ancestral canoes, and they represented guardian spirits for Maori at sea. The presence of a whale near or stranded on land was a symbol of rich food and abundance and thus indicated a good place to settle. This symbolism is evident in the use of stylised whale shapes on barge boards of storage houses to represent the bounty within. Whale bone from stranded whales was used for clubs, cloak pins, combs, and ornamental fish-hooks, often presented as highly prized gifts. Some small rib bones were used as "spreaders" or pekapeka from which three fish-hooks were suspended. Species known to Maori include the southern right whale and the humpback whale.
Maori did not traditionally hunt whales, but once whalers from the northern hemisphere nations began exploiting whales in the southern hemisphere in the 1790s, Maori joined in the hunt and ran several whaling stations. The bones from these whales were buried for 12 months until they were white, and were then used for walking sticks, battle axes, spears, and meremere.
Key References
Anon. 2005. The Conservation of Whales in the 21st Century. Department of Conservation, Wellington, New Zealand. 32pp.
Evans, P G H. 1987. The Natural History of Whales and Dolphins. Christopher Helm, London. 343pp.
Folkens, P A, Reeves, R R, Stewart, B S, Clapham, P J and J A Powell. 2002. Guide to Marine Mammals of the World. National Audubon Society. Alfred A. Knopf Inc. 528pp.
Gaskin, D E. 1972. Whales dolphins and seals with special reference to the New Zealand region. Heinemann Educational Books Ltd. 200pp.
Hoelzel, A R (ed). 2002. Marine Mammal Biology: An evolutionary approach. Blackwell Science Ltd, Oxford. 432pp.
Orbell, M. 1985. The Natural World of the Maori. William Collins Publishers, New Zealand. 230pp.
Perrin, W F, Würsig, B and, J G M Thewissen (eds). 2002. Encyclopedia of Marine Mammals. San Diego: Academic Press. 1414pp.
Poata, T. 1989. The Maori as a fisherman and his methods. Southern Reprints. 27pp.
Shirihai, H. 2002. The Complete Guide to Antarctic Wildlife: Birds and marine mammals of the Antarctic Continent and the Southern Ocean. Princeton University Press, Princeton, New Jersey. 510pp.
Table 8: Baleen Whales (Families Balaenidae, Balaenopteridae, and Neobalaenidae) in New Zealand
| Taxon | Common name | Status in New Zealand region | IUCN status | DoC status |
|---|---|---|---|---|
| Family Balaenidae | ||||
| Eubalaena australis | Southern right whale | Breeds | Lower risk-conservation dependent | Nationally endangered |
| 1 | ||||
| Family Balaenopteridae | ||||
| Balaenoptera acutorostrata subsp. | Dwarf minke whale | Breeds | Insufficiently known | Not threatened |
| Balaenoptera bonaerensis | Antarctic minke whale | Migrant | Lower risk-conservation dependent | Migrant |
| Balaenoptera borealis | Sei whale | Migrant | Endangered | Migrant |
| Balaenoptera edeni | Bryde's whale | Breeds | Data deficient | Nationally critical |
| Balaenoptera musculus | Blue whale | Migrant | Endangered | Migrant |
| Balaenoptera musculus brevicauda | Pygmy blue whale | Migrant | Data deficient | Migrant |
| Balaenoptera physalus | Fin whale | Migrant | Endangered | Migrant |
| Megaptera novaeangliae | Humpback whale | Migrant | Vulnerable | Migrant |
| 8 | ||||
| Family Neobalaenidae | ||||
| Caperea marginata | Pygmy right whale | Migrant | Insufficiently known | Data deficient |
| 1 | ||||
| Total | 10 |