A | B | C | D | E | F | G | H | CH | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
| Southern right whale[1] | |
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Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Infraorder: | Cetacea |
| Family: | Balaenidae |
| Genus: | Eubalaena |
| Species: | E. australis
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| Binomial name | |
| Eubalaena australis (Desmoulins, 1822)
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| Range | |
| Synonyms[4] | |
| |
The southern right whale (Eubalaena australis) is a baleen whale, one of three species classified as right whales belonging to the genus Eubalaena. Southern right whales inhabit oceans south of the Equator, between the latitudes of 20° and 60° south.[5] In 2009 the global population was estimated to be approximately 13,600.[6]
Taxonomy
Right whales were first classified in the genus Balaena in 1758 by Carl Linnaeus, who at the time considered all right whales (including the bowhead) to be a single species. In the 19th and 20th centuries the family Balaenidae was the subject of great taxonometric debate. Authorities have repeatedly recategorised the three populations of right whale plus the bowhead whale, as one, two, three or four species, either in a single genus or in two separate genera. In the early whaling days, they were all thought to be a single species, Balaena mysticetus.[7]
The southern right whale was initially described as Balaena australis by Desmoulins in 1822. Eventually, it was recognised that bowheads and right whales were different, and John Edward Gray proposed the genus Eubalaena for the right whale in 1864. Later, morphological factors such as differences in the skull shape of northern and southern right whales indicated at least two species of right whale—one in the Northern Hemisphere, the other in the Southern Ocean.[7] As recently as 1998, Rice, in his comprehensive and otherwise authoritative classification, Marine mammals of the world: systematics and distribution, listed just two species: Balaena glacialis (all of the right whales) and Balaena mysticetus (the bowheads).[8]
In 2000, Rosenbaum et al. disagreed, based on data from their genetic study of DNA samples from each of the whale populations. Genetic evidence now shows that the northern and southern populations of right whale have not interbred for between 3 million and 12 million years, confirming the southern right whale as a distinct species. The northern Pacific and Atlantic populations are also distinct, with the North Pacific right whale being more closely related to the southern right whale than to the North Atlantic right whale.[9] Genetic differences between E. japonica (North Pacific) and E. australis (South Pacific) are much smaller than other baleen whales represent among different ocean basins.[10]
It is believed that the right whale populations first split because of the joining of North and South America. The rising temperatures at the equator then created a second split, into the northern and southern groups, preventing them from interbreeding.[11]
In 2002, the Scientific Committee of the International Whaling Commission (IWC) accepted Rosenbaum's findings, and recommended that the Eubalaena nomenclature be retained for this genus.[12]
The cladogram is a tool for visualising and comparing the evolutionary relationships between taxa. The point where a node branches off is analogous to an evolutionary branching – the diagram can be read left-to-right, much like a timeline. The following cladogram of the family Balaenidae serves to illustrate the current scientific consensus as to the relationships between the southern right whale and the other members of its family.
| Family Balaenidae | |||||||||||||||||||||
| |||||||||||||||||||||
| The right whale family, Balaenidae[9] |
Other junior synonyms for E. australis have included B. antarctica (Lesson, 1828), B. antipodarum (Gray, 1843), Hunterus temminckii (Gray, 1864), and E. glacialis australis (Tomilin, 1962) (see side panel for more synonyms).[1][4]
Description
Like other right whales, the southern right whale is readily distinguished from others by the callosities on its head, a broad back without a dorsal fin, and a long arching mouth that begins above the eye. Its skin is very dark grey or black, occasionally with some white patches on the belly. The right whale's callosities appear white due to large colonies of cyamids (whale lice). It is almost indistinguishable from the closely related North Atlantic and the North Pacific right whales, displaying only minor skull differences. It may have fewer callosities on its head than North Atlantic and more on its lower lips than the two northern species.[7][13] The biological functions of callosities are unclear, although protection against predators has been put forward as the primal role.[citation needed]
An adult female is 15 m (49 ft)[14] and can weigh up to 47 tonnes (46 long tons; 52 short tons),[14] with the larger records of 17.5–18 m (57–59 ft)[15][16] in length and 80 tonnes (79 long tons; 88 short tons)[17] or up to 90 tonnes (89 long tons; 99 short tons) in weight,[18] making them slightly smaller than other right whales in the Northern Hemisphere.[19] The testicles of right whales are likely to be the largest of any animal, each weighing around 500 kg (1,100 lb). This suggests that sperm competition is important in the mating process.[20]
The proportion and numbers of molten-coloured individuals are notable in this species compared with the other species in the Northern Hemisphere. Some whales remain white even after growing up.[21]
Life span is not clear although whales seem to reach over 100 years old.[22]
Behaviour
Like other right whales, they are rather active on the water surface and curious towards human vessels. Southern rights appear to be more active and tend to interact with humans more than the other two northern species.[citation needed] One behaviour unique to the southern right whale, known as tail sailing, is that of using their elevated flukes to catch the wind, remaining in the same position for a considerable amount of time. It appears to be a form of play and is most commonly seen off the coast of Argentina and South Africa.[13] Some other species such as humpback whales are also known to display. Right whales are often seen interacting with other cetaceans, especially humpback whales[23] and dolphins. There have been records of southern rights and humpbacks thought to be involved in mating activities off Mozambique,[24] and along Bahia, Brazil.[25]
On several occasions, calving mothers have been recorded to nurse non-offspring calves along with their own calves.[26] Additionally, a female was seen to accompany a lone humpback whale calf although the actual relationship of this pair is unclear.[27]
Reproduction
Southern right whales display strong maternal fidelity to their calving grounds.[28][29] Calving females are known to return to calving grounds at 3-year intervals.[30] The most commonly observed calving interval is 3 years, but intervals can range from 2 to 21 years.[31][32] Calving takes place between June and November[33] in calving grounds between 20 and 30° S.[34]
In Australia, southern right whales have shown a preference for calving grounds along coastlines with high wave energy, such as the Head of the Bight. Here, the sound of breaking waves may mask the sound of the whales' presence, and so protect infants and calving cows from predators such as killer whales. Deep waters alongside shallower calving grounds may serve as training grounds for calves to build up their stamina ahead of migration.[35]
Females give birth to their first calf when they are between eight and ten years old.[36] A single calf is born after a gestation period of one year, about 1 short ton (0.91 t) in weight and 4–6 m (13–20 ft) in length.[37] The calf usually remains with its mother during the first year of its life, during which time it will double in length.[5]
This species has been recognized to nurse unrelated orphans on occasions.[38]
Feeding
Like right whales in other oceans, southern right whales feed almost exclusively on zooplankton, particularly krill.[5] They feed just beneath the water's surface, holding their mouths partly open and skimming water continuously while swimming. They strain the water out through their long baleen plates to capture their prey. A southern right whale's baleen can measure up to 2.8 m (9 ft 2 in) long, and is made up of 220-260 baleen plates.[33]
Population and distribution
The global population of southern right whales was estimated at 13,611 in 2009.[6] An estimate published by National Geographic in October 2008 put the southern whale population at 10,000. An estimate of 7,000 followed a March 1998 IWC workshop. Researchers used data about adult female populations from three surveys (one in each of Argentina, South Africa and Australia, collected during the 1990s) and extrapolated to include unsurveyed areas, number of males and calves using available male:female and adult:calf ratios to give an estimated 1999 figure of 7,500 animals.[39] Recovery of the overall population size of the species is predicted to be at less than 50% of its pre-whaling state by 2100 due to heavier impacts of whaling and slower recovery rates.[40] Since hunting ceased, the population is estimated to have grown by 7% a year.
The southern right whale spends summer in the far Southern Ocean feeding, probably close to Antarctica. If the opportunity arises, feeding can occur even in temperate waters such as along Buenos Aires.[41][42] It migrates north in winter for breeding and can be seen by the coasts of Argentina, Australia, Brazil, Chile, Namibia, Mozambique, Peru, Tristan de Cunha, Uruguay, Madagascar, New Zealand and South Africa; whales have also been known to winter in sub-Antarctic regions.[43][44] It appears that the South American, South African and Australasian groups intermix very little if at all, because maternal fidelity to feeding and calving habitats is very strong. The mother also passes these choices to her calves.[45]
Right whales do not normally cross the warm equatorial waters to connect with the other species and (inter)breed: their thick layers of insulating blubber make it difficult for them to dissipate their internal body heat in tropical waters. Based on historical records and unconfirmed sightings in modern periods, E. australis transits may sometimes occur through equatorial waters.[46]
Whaling records for the hemisphere include a whaling ground in the central northern Indian Ocean[47] and recent sightings among near-equatorial regions. If the sighting off Kiribati was truly of E. australis, this species may have crossed the Equator on irregular occasions and their original distributions might have been much broader and more northerly distributed than is currently believed.[46][48] A stranding of a 21.3 m (71 feet) right whale at Gajana, northwestern India in November 1944 was reported, but the true identity of this animal is unclear.[49][50]
Aside from impacts on whales and environments caused by mankind, their distributions and residences could be largely affected by presences of natural predators or enemies,[43] and similar trends are also probable for other subspecies.[51]
Many locations throughout the Southern Hemisphere were named after current or former presences of southern rights, including Walvis Bay, Punta Ballena, Right Whale Bay, Otago Harbour, Whangarei Harbour, Foveaux Strait,[52] South Taranaki Bight, Moutohora Island and Wineglass Bay.
Africa
South Africa
Hermanus in South Africa has become known as a centre for whale watching. During the Southern Hemisphere winter months (June – October) the southern right whales migrate to the coastal waters of South Africa, with more than 100 whales known to visit the Hermanus area. Whilst in the area, the whales can be seen with their young as they come to Walker Bay to calve and mate. Many behaviours such as breaching, sailing, lobtailing, or spyhopping can be witnessed. In False Bay whales can be seen from the shore from July to October while both Plettenberg Bay and Algoa Bay are also home to the southern right whales from July to December. They can be viewed from land as well as by boat with licensed operators conducting ocean safaris throughout the year.
Recent increases in numbers of whales visiting the north-eastern part of South Africa, the so-called Dolphin Coast such as around Ballito[53] and off Umdloti Beach,[54] indicates the whales' normal ranges are expanding and that re-colonising historical habitats will likely continue as more whales migrate further north.
Western Africa
In Namibia, the majority of confirmed whales are restricted to the south of Luderitz, on the southwestern coast. Only a handful of animals venture further north to historical breeding grounds such as at Walvis Bay, but their numbers are slowly increasing. Until illegal hunting ceased, whales were rare along Namibian shores, with no sighting recorded north of Orange River until 1971.[55] Calving activities were first confirmed as recently as the 1980s.[56]
Historical records suggest that this whale's regular range could have once reached further northwards up the coasts of Cape Fria (northern Namibia)[57] and Angola as far as Baia dos Tigres (Tiger Bay).[58][57]
Whaling is known to have been carried out off the coast of Gabon,[46] for example at Cape Lopez, and there have been a few confirmed and unconfirmed sightings including one by Jim Darling, a renowned whale researcher.[59][60][61]
Eastern Africa
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Southern right whales have been spotted in very small numbers off Mozambique[62] and Madagascar.[63] Whales were historically seen in large numbers at various locations such as off the coast of Durban, in Delagoa/Maputo Bay,[64] Inhaca Island, Ponta do Ouro, and around the Bazaruto Archipelago.[24] The first sighting off Mozambique since the end of whaling was in 1997.[65] In recent years, more whales seem to migrate further north to calve, such as at Île Sainte-Marie,[66][67][68][69] Antongil Bay,[60] Fort Dauphin[70] Toliara,[71] Anakao, Andavadoaka, and Antsiranana Bay,[72][73][74] at Madagascar's northern tip. Infrequent sightings have been confirmed off the island of Mayotte.[75] Whales were historically taken off the coast of Tanzania, and may still be present occasionally around Zanzibar.[76]
Mid–South Atlantic
Due to illegal whaling by the USSR, the recovery of many stocks including the population off Tristan da Cunha[77] and adjacent areas such as Gough Island has been severely hindered, resulting in relatively few numbers of visiting animals.
Based on catch records and recent observations, right whales may be seen as far north as the islands of Saint Helena and Ascension Island.[48][78]
South America
Brazil
In Brazil, more than 300 individuals have been cataloged through photo identification (using head callosities) by the Brazilian Right Whale Project, maintained jointly by Petrobras (the Brazilian state-owned oil company), and the conservation group, the International Wildlife Coalition. The State of Santa Catarina hosts a concentration of breeding and calving right whales from June to November, and females from this population also calve off Argentinian Patagonia and Uruguay. In recent years, possibly due to changing habitat environments by human activities and conflicts with local fisheries, the number of whales visiting the coasts is decreasing.[79] Sighting in locations other than Santa Catarina and Rio Grande do Sul[80] remain sporadic, such as along Cidreira,[81] Rio de Janeiro coasts like Sepetiba Bay (pt),[82] Cabo Frio,[83][84] Macaé,[85] Prado, Bahia,[86][87] Castelhanos Bay in Ilha Bela,[88][89][90] São Paulo coasts[91] such as within Ilha Anchieta State Park,[92] Honey Island,[93][94][95] and bays and estuaries of Paranaguá and Superagui National Park,[96] Paraná,[97][98][99] and even entering into the lagoon of Lagoa dos Patos.[100][101] Recent studies[102] also show a decrease in the number of sightings along the southeastern Brazilian coast, which includes the highly urbanized States of São Paulo and Rio de Janeiro.
Further north, small numbers of whales migrate every year to winter or calve in Bahia,[25] in particular at the Abrolhos Archipelago. Here, certain individuals are recorded returning at intervals of 3 or 4 years.[103] Whaling records including those prior to Maury and Townsend indicate that right whales were once more frequent visitors further north, for example at Salvador, Bahia.[46][48]
Argentina
Argentina hosts the world's largest breeding population of southern right whales at Península Valdés, Chubut province, with over 2000 estimated individuals gathering on the gulfs of the peninsula during breeding season. The whales are considered a "natural monument" and protected under Argentine law, and there is a developed whale-watching tourism around them.
During the 2012 annual meeting of the International Whaling Commission's Scientific Committee, data was presented regarding the continued phenomenon of southern right whale strandings and high rate of mortality at Península Valdés. Between 2003 and 2011, a total of 482 dead right whales were recorded at Península Valdés. There were at least 55 whale deaths in 2010, and 61 in 2011. As in previous years, the vast majority of strandings were calves of the season.[104] There have been increasing sightings in various other locations in recent years, such as on Golfo San Jorge,[105] Tierra del Fuego,[106][107] Puerto Deseado,[108][109] Mar del Plata,[110][111] Miramar, Buenos Aires,[112][113] and Bahía Blanca.[114]
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