Right whale

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Gray, 1821 Template:Taxobox genus entry Template:Taxobox end placement Template:Taxobox section subdivision  Balaena mysticetus, Bowhead Whale
 Eubalaena australis, Southern Right Whale
 Eubalaena glacialis, Atlantic Northern Right Whale
 Eubalaena japonica, Pacific Northern Right Whale Template:Taxobox image Template:Taxobox image Template:Taxobox image Template:Taxobox end

The right whales are the baleen whales belonging to the family Balaenidae. There are four species in two genera: Eubalaena (three species) and Balaena (one species, the Bowhead Whale).

Right whales grow to 18 m (60 ft) long and weigh up to 100 metric tons. They are mostly black, very rotund and have distinctive white callosities (skin abrasions) on their heads. They are called "right whales" because whalers thought the whales were the "right" ones to catch because they float when killed. Populations were vastly reduced by intensive harvesting during the active years of the whaling industry. Nowadays, instead of hunting them, people often watch this acrobatic family for pleasure. The three right whale species live in geographically distinct locations. Around 300 Atlantic Northern Right Whales live in the North Atlantic, while North Pacific has approximately 200 Pacific Northern Right Whales. Finally, about 7,500 Southern Right Whales are spread throughout the southern part of the southern hemisphere.

Taxonomy

After many years of shifting views on the number of right whale species, recent genetic evidence has led scientists in the field to conclude that there are in fact three distinct right whale species.

The Bowhead Whale is clearly an individual species and has always been recognized as such. Today the species still stands alone in its own genus as it has done since the work of Gray in 1821. There is, however, little genetic evidence to support this two-genera view. Indeed, scientists see greater differences between the members of Balaenoptera than between the Bowhead Whale and the right whales. Thus, it is likely that all four species will be placed in one genus in some future review.

In dealing with the three populations of right whales, authorities have historically disagreed over whether to categorize the three populations in one, two or three species. In the whaling days there was thought to be a single worldwide species. Later, morphological factors such as small differences in the skull shape of northern and southern animals lent support to the view that there were at least two species—one found only in the northern hemisphere, the other found in the Southern Ocean). Furthermore, no group of right whales has been known to swim through warm equatorial waters to make contact with the other (sub)species and (inter)breed; their thick layers of insulating blubber make it impossible for them to shed their internal heat in tropical waters.

In recent years, genetic studies have provided clear evidence that the northern and southern populations have not interbred for between 3 million and 12 million years, confirming the status of the Southern Right Whale as a distinct species. More surprising has been the finding that the northern hemisphere Pacific and Atlantic populations are also distinct, and that the Pacific species (now known as the Pacific Northern Right Whale), is in fact more closely allied with the Southern Right Whale than with the Atlantic Northern Right Whale. Whilst Rice continued to list two species in his 1998 classification, this was disputed by Rosenbaum et al (2000)  and Brownell et al (2001) . In 2005, Mammal Species of the World listed three species, indicating a seemingly more permanent shift to this preference.

Confirmation of the three species theory

"Whale lice", parasitic cyamid crustaceans that live off skin debris, offer further information on right whale populations through their own genetic patterns. Because the lice reproduce much more quickly than whales, their genetic diversity is greater. Marine biologists at the University of Utah examined these lice genes and determined that their hosts split into three species 5–6 million years ago, and that these species were all equally abundant before whaling began in the 11th century. The communities were first split off because of the joining of North and South America. The heat of the equator then separated them further into northern and southern groups.

The fossil record

See also: Evolution of cetaceans

A total of five Balaena fossils have been found in Europe and North America in deposits ranging from the late Miocene (~10 mya) to early Pleistocene (~1.5 mya). These five records have each been accorded their own species status—B. affinis, B. etrusca, B. montalionis, B. primigenius and B. prisca. The last of these may yet prove to be the same as the modern Bowhead Whale.

Prior to these there is a long gap back to the next related cetacean in the fossil record—Morenocetus was found in a South American deposit dating back 23 million years.

Synonyms and other common names

Due to their familiarity to whalers over a number of centuries the right whales have been given many names. These names were applied to right whales throughout the world, reflecting the fact that only one species was recognised at this time. In his novel Moby-Dick, Herman Melville writes: "Among the fishermen, [the whale regularly hunted for oil] is indiscriminately designated by all the following titles: The Whale; the Greenland Whale; the Black Whale; the Great Whale; the True Whale; the Right Whale."

Halibalaena (Gray, 1873) and Hunterius (Gray, 1866) are junior synonyms for the genus Eubalaena. E. australis is the type species.

The species-level synonyms are:

For E. australis: antarctica (Lesson, 1828), anitpodarum (Gray, 1843), temminckii (Gray, 1864)

For E. glacialis: biscayensis (Eschricht, 1860), nordcaper (Lacepede, 1804)

For E. japonica: sieboldii (Gray, 1864)

Physical description

An Atlantic Northern Right Whale, clearly showing the distinctive callosities and curved mouth.

A Southern Right Whale in the breeding grounds at Peninsula Valdés in Patagonia.

Drawing of a Pacific Northern Right Whale.

An Atlantic Northern Right Whale on a Faroese stamp.

Right whales are easily distinguished from other whales by the large number of callosities on their heads, a thick back without a dorsal fin, and a long drooping mouth that begins high above the eye and then arches round beneath it. The body of the whale is very dark grey or black with some white patches on the belly. The white patches on the whale's skin around the callosites are not due to skin pigmentation, but are actually large colonies of whale lice buried in the whale's skin.

Adults may be between 11–18 m (36–59 ft) in length and typical weigh 60 to 80 metric tons. The most typical lengths are 13–16 m. The body is extremely robust with girth as much as 60% of total body length in some cases. The tail fluke is also broad (up to 40% of body length). The North Pacific species is on average the largest of the three. The largest specimens of these may weigh 100–metric tons.

Right whales have between 200 and 300 baleen plates on each side of the mouth. These are narrow, approximately 2 m long and are covered in very thin hairs. The plates enable the whale to feed (see Diet below). The testicles of the right whale are likely to be the largest of any animal, each weighing around 500 kg. At 1% of the whale's total body weight, this size is very large even taking into account the size of the whale. This suggests that sperm competition is important in the mating process. Right whales have a distinctive wide V-shaped blow, caused the widely-spaced blowholes on the top of the head. The blow rises to 5 m above the ocean's surface.

Females reach sexual maturity at 6–12 years and breed every 3–5 years. Both reproduction and calving take place during the winter months. Calves are approximately 1 metric ton (1.1 short tons) in weight and 4–6 m in length at birth following a gestation period of 1 year. The right whale grows rapidly in its first year, typically doubling in length. Weaning occurs after eight months to one year and the growth rate in later years is not well understood—it may be highly dependent on whether a child stays with its mother for a second year.

Very little is known about the life span of right whales. One of the few pieces of evidence is the case of a mother Atlantic Northern Right Whale that was photographed with a baby in 1935, then photographed again in 1959, 1980, 1985 and 1992, with callosity patterns being used to ensure it was the same animal. Finally, she was photographed in 1995 with a seemingly fatal head wound that is presumed to have been caused by a ship strike. The animal was around 70 years of age at death. Research on Bowhead Whales suggest reaching this age is not uncommon and may even be exceeded.

The distinctive V-shaped blow of a right whale.

Right whales are slow swimmers, reaching only 5 knots at top speed, but are highly acrobatic and frequently breach (jump clear of the sea surface), tail-slap and lobtail. Like other baleen whales, the species is not gregarious and the typical group size is only two. Larger groups of up to twelve have been reported, but these were not close-knit and may have been transitory.

The right whale's only predators are the killer whale and some of the larger sharks. When danger lurks, a group of right whales may come together in a circle, with their tails pointing outwards, in order to deter the predator. This defence is not always successful and calves are occasionally separated from their mother and killed.

Diet

The right whales' diet consists primarily of zooplankton and tiny crustaceans such as copepods, krill, and pteropods, although they are occasionally opportunistic feeders. They feed by "skimming" along with their mouth open. Water and prey enters the mouth but only the water can pass through the baleen and out again into the open sea. Thus, for a right whale to feed on a given prey animal, the animal must occur in sufficient density to trigger the whale's interest and be large enough that the baleen plates can filter it but small enough that it doesn't have the speed to escape. The "skimming" may take place on the surface (where it can be spectacular to watch), underwater or even close to the ocean's bottom, indicated by mud occasionally observed on right whales' bodies.

Sound production and hearing

See also: Whale song

Vocalizations made by right whales are not elaborate compared to those made by other whale species. The whales do make groans, pops and belches that are typically around 500 Hz. The purpose of the sounds is not known but is likely to be a form of communication between whales within the same group.

A report published in the Proceedings of the Royal Society B in December 2003 suggested that Northern Rights responded rapidly on hearing sounds similar to police sirens—sounds of much higher frequency than those made by whales. On hearing the sounds they moved rapidly to the surface. The research was of particular interest because it is known that Northern Rights ignore most sounds, including those of approaching boats. Researchers speculate that this information may be useful in attempts to reduce the number of ship-whale collisions.

Whaling

Whaling in small wooden boats with hand harpoons was a hazardous enterprise, even when hunting the "right" whale.

See also: Whaling

Right whales were so named because whalers thought they were the "right" whale to hunt. 40% of a right whale's body weight is blubber, which is of relatively low density. In consequence, unlike other whales, right whales float when they die and were thus easy to catch even for men equipped only with frail wooden boats and hand-held harpoons. Right whales' slowness through the water was a great asset as far as the whalers were concerned.

The Basques were the first to hunt right whales. They began doing so as early as the 11th century in the Bay of Biscay. The whales were hunted initially for their oil but, as meat preservation technology improved, the animal was also used for food. As populations close to modern-day Spain became depleted, the whalers headed steadily further afield. They reached eastern Canada by 1530  and the shores of Todos os Santos Bay (nowadays in Bahia in Brazil) by 1602. Basque whaling was at its peak for the next one hundred years with 300–500 animals taken each year. The take then tailed off and the fishery finally ceased operation in 1713.

Basques were replaced by the whalers from the new American colonies, the "Yankee whalers". Setting out from Nantucket, Massachusetts and Long Island, New York, the Americans were able to take up to 100 right whales in good years. By 1750 the Atlantic Northern Right Whale was as good as extinct for commercial purposes and the Yankee whalers moved into the South Atlantic before the end of the 18th century. The southernmost Brazilian whaling station was established in 1796, in Imbituba. Over the next one hundred years, Yankee whaling spread into the Southern and Pacific Oceans, where the Americans were joined by fleets from several European nations and Japan. The beginning of the 20th century saw much greater industrialization of whaling, and the takes grew rapidly. By 1937, there had, according to whalers' records, been 38,000 takes in the South Atlantic, 39,000 in the South Pacific, 1,300 in the Indian Ocean and 15,000 in the north Pacific. Given the incompleteness of these records, the actual take was somewhat higher.

As it became clear that stocks were nearly destroyed, a worldwide total ban on right whaling was agreed upon in 1937. The ban was largely successful, although some whaling continued in violation of the ban for several decades. Madeira took its last two right whales in 1968. Japan took 23 Pacific right whales in the 1940s and more under scientific permit in the 1960s. Illegal whaling continued off the coast of Brazil for many years and the Imbituba land station processed right whales until 1973.

The Soviet Union is now known to have illegally taken at least 3,212 Southern Right Whales during the 1950s and 60s, although it only reported taking 4. The full size of the Soviet take may never be known.

Population and distribution today

Estimating whale abundance

Because the oceans are so large it is very difficult to accurately gauge the size of a whale population. The estimate of 7,000 Southern Right Whales came about following a workshop of a IWC workshop held in Cape Town in March 1998. Researchers counted used data about number of adult females 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 ratio data to give an estimated 1999 figure of 7,000 animals. Further information may be obtained from the May 1998 edition of "Right Whale News" available online.

Today, the three right whale species inhabit three distinct areas of the globe, the Atlantic Northern in the western Atlantic Ocean, the Pacific Northern in a band from Japan to Alaska and the Southern in all areas of the Southern Ocean. The whales can only cope with the moderate temperatures between 20 and 60 degrees in latitude. Thus the warm waters of the equatorial region form a barrier and prevent the northern and southern groups inter-mixing. Although the Southern species in particular must travel across open ocean to reach its feeding grounds, the species is not considered to be pelagic. In general, they prefer to stay close to peninsulas and bays and on continental shelves, as these areas offer greater shelter and abundance of their preferred food.

A female Atlantic Northern Right Whale with her calf.

There are about 300 Atlantic Northern Right Whales, almost all living in the western North Atlantic. In spring, summer and autumn, they feed in areas off the Canadian and north-east US coasts in a range stretching from North Carolina to Nova Scotia. Particularly popular areas appear to be the Bay of Fundy and Grand Manan Island. In winter, they head south towards Georgia and Florida in order to mate and, a year later, give birth.

There have been a smattering of sightings further east over the past few decades—several sightings were made close to Iceland in 2003. It is possible that these are the remains of a virtually extinct eastern Atlantic stock but examination of old whalers records suggest that they are more likely to be strays from further west.

Only about 200 North Pacific right whales survive. Thus, the two northern right whale species are the most endangered of all large whales and two of the most endangered animals in the world. Based on current population density trends, both species are predicted to become extinct within 200 years. The Pacific species was historically found from the southern tip of Japan, across the Bering Strait and down the North American coast as far as California. Today, sightings are very rare and generally occur in the mouth of the Sea of Okhotsk and in the eastern Bering Sea. Although this species is very likely to be migratory like the other two species, its movement patterns over the year are not known.

Southern Right Whales spend the summer months in the far Southern Ocean feeding, probably close to Antarctica. They migrate north in winter for breeding and can be seen around the coasts of Chile, Argentina, Brazil, South Africa, Mozambique, Australia and New Zealand. The total population is estimated to be between seven and eight thousand. Since hunting of the Southern Right Whale ceased, stocks are estimated to have grown by 7% a year. It appears that the South American, South African and Australasian groups intermix very little, if at all, because the fidelity of a mother to its feeding and calving habitats is very strong. The mother also passes these instincts to her calves.

In Brazil, more than 300 individuals have been cataloged through photo-identification (using their distinctive head callosities) by the Brazilian Right Whale Project, maintained jointly by Petrobras (the Brazilian state-owned oil company) and 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 are also known to calve off Argentinian Patagonia.

Conservation

The remains of an Atlantic Northern Right Whale after it has collided with a boat propeller.

The leading cause of death among Atlantic Northern Right Whales, which migrate through some of the world's busiest shipping lanes whilst journeying off the east coast of the United States, is injuries sustained from colliding with ships. At least 16 reported deaths due to ship strikes were reported between 1970 and 1999, and probably many more remain unreported.. Recognising that this toll could tip the balance of the already delicately poised species towards extinction, the United States government introduced measures to curb the decline. The National Oceanic and Atmospheric Administration's Atlantic Large Whale Take Reduction Plan  was introduced in 1997. A key part of the plan was the introduction of mandatory reporting of large whale sightings by ships using U.S. ports. This requirement was implemented in July 1999.

Whilst environmental campaigners were, as reported in 2001, pleased that the reporting plan has a positive effect, they wanted the government to do more. In particular they demanded that ships within 25 miles of U.S. ports in times of known high right whale conservation be forced to maintain a speed of no more than 12 knots. The United States government, citing concerns about excessive disruption to trade, did not enforce such measures. The conservation groups Defenders of Wildlife, the Humane Society of the United States and the Ocean Conservancy thus sued the National Marine Fisheries Service (a sub-agency of the NOAA) in September 2005 for "failing to protect the critically endangered North Atlantic Right Whale, which the agency acknowledges is 'the rarest of all large whale species' and which federal agencies are required to protect by both the Marine Mammal Protection Act and the Endangered Species Act," and demanded that emergency measures be put in place to protect the whales. The legal wranglings are currently continuing. Both the North Atlantic and North Pacific species are listed as "endangered" by CITES and the IUCN, and under the U.S. Endangered Species Act.

The Southern Right Whale is protected in the jurisdictional waters of all countries with known breeding populations (Argentina, Australia, Brazil, Chile, New Zealand, South Africa and Uruguay). In Brazil, a federal Environmental Protection Area encompassing some 1,560 square kilometres (and 130 km of coastline) in Santa Catarina State was established in 2000 to protect the species' main breeding grounds in Brazil and promote regulated whale watching. The species is listed as "lower risk - conservation dependent" by the IUCN. CITES lists the species as "endangered".

Whale watching

A Southern Right Whale approaches close to whale watchers near Península Valdés in Patagonia.

See also: Whale watching

Southern Right Whales have made Hermanus, South Africa one of the world centers for whale watching. During the winter months (July–October), Southern Right Whales come so close to the shoreline that visitors can watch whales from their (deliberately placed) hotels. The town employs a "whale crier" (cf. town crier) to walk through the town announcing where whales have been seen. Southern Right Whales can also be watched at other winter breeding grounds.

In Brazil, Imbituba in Santa Catarina has been recognized as the National Right Whale Capital and holds annual Right Whale Week celebrations in September, when mothers and calves are more often seen. The old whaling station there has been converted to a museum documenting the history of right whales in Brazil. In Argentina, Península Valdés in Patagonia hosts (in winter) the largest breeding population of the species, with more than 2,000 animals catalogued by the Whale Conservation Institute and Ocean Alliance.

References

Further general references