North Atlantic right whale (Eubalaena glacialis)
|French:||Baleine De Biscaye, Baleine Des Basques|
|Spanish:||Ballena, Ballena Franca Del Norte, Ballenga|
|Size||Length: 13 – 16 m (2)|
|Weight||up to 70 tonnes (3)|
Classified as Endangered (EN) by the IUCN Red List (1) and listed on Appendix I of CITES (4).
The North Atlantic right whale is currently one of the rarest large whales in the world, having been drastically reduced to critically low numbers by years of exploitation (2). Its robust, somewhat rotund, body is mostly black, with a large head that measures up to one third of the total body length. Some individuals may also bear white patches on the underside, while others have a more mottled appearance. More often, the only conspicuous feature of this great whale are the irregular patches of thickened tissue, called callosites, on the head. These callosites are inhabited by many small amphipods, known as cyamids or whale lice, and form a pattern unique to each individual whale, thus providing a means of identification (2). The North Atlantic right whale lacks a dorsal fin (2), but has large, paddle-like pectoral fins used for steering (2) (5), and an enormous tail that provides propulsion with powerful vertical strokes (2) (5). The downward-curved mouth of the North Atlantic right whale contains between 200 and 270 baleen plates on each side of the upper jaw (2). These plates, each measuring around two metres long and fringed with fine hairs (2), replace teeth in Balaenidae whales, and are central to their method of feeding (5). The North Atlantic right whale has two blowholes situated on top of its head through which it breathes, producing a distinctive, bushy, v-shaped cloud of spray when it exhales at the surface (5) (6).
Historically, the North Atlantic right whale was far more widespread than it is now, and was once common on both sides of the Atlantic (1), from Labrador, Greenland, Iceland and Norway south to Florida and north-western Africa (2). Today, this whale appears to be effectively extinct in the eastern North Atlantic (1), and it survives only in the western North Atlantic, from Florida to Nova Scotia (2).
This marine mammal migrates between two vital habitats: feeding grounds and calving grounds (2). Its feeding grounds are in the north of its range, where a combination of factors such as temperature, ocean bottom topography and currents interact to aggregate zooplankton into dense concentrations (2). The North Atlantic right whale’s calving grounds are situated in warmer waters in the south of its range, in shallow coastal waters or bays (2).
Remarkably for their large size, North Atlantic right whales feed only on tiny planktonic prey, including large copepods, the size of a grain of rice; krill, a shrimp-like crustacean; tiny planktonic snails and the drifting larval stages of barnacles and other crustaceans (2). North Atlantic right whales are ‘skim feeders’, which feed by swimming forward with their mouth open, allowing water to flow into the mouth and out through the baleen (2). Tiny prey is strained from the water as it becomes caught in the fringed baleen, where it is then dislodged by the tongue and swallowed (5). Although they often feed at the ocean surface, or just below, the North Atlantic right whale is also believed to feed close to the bottom, as it has been seen surfacing after a 10 to 20 minute dive with mud on its head (2).
After feeding at northern latitudes during the summer, the North Atlantic right whale migrates south for winter. Pregnant females head for the inshore calving grounds, whilst the location of the remaining majority of the population is not known. Wherever they head, this is the time at which mating takes place (2). North Atlantic right whale females typically first calve at nine to ten years of age, and then give birth to a single young every three years. The gestation period lasts for about one year, and following birth, the mother and her young remain close until the calf is weaned at the age of one (2). During its first year of life the calf learns the location of critical feeding grounds from its mother, which it will continue to visit for the remainder of its life. The female then takes a third year to replenish her energy stores before breeding again (2).
Today, the North Atlantic right whale is a rarely seen animal, but its name refers to a time when they were more frequently observed, when they swam slowly, close to shore, thus making them an easy target for whalers. Not only did this swimming behaviour make this whale the ‘right’ one to hunt, but it also floated when dead and yielded vast quantities of valuable oil and baleen (2). Despite its bulky size, the North Atlantic right whale is able to perform acrobatic acts such as jumping out of the water, known as breaching, violently slapping the water surface with the tail and slapping the surface with a pectoral fin (2). Although the purpose of these behaviours is not fully understood, they may be used in communication. Similarly, the range of low frequency groans, moans and belches that the North Atlantic right whale makes are hypothesized to be used to communicate with other individuals, or signal aggression (2).
With, as of 2008, between just 300 and 350 North Atlantic right whales remaining, this species’ existence lies in an extremely precarious situation (1). Years of whaling, starting in the 11th century and becoming a modern industrial practice in the early 20th century, have left North Atlantic right whale stocks seriously depleted in the western Atlantic (2), and virtually extinct in the eastern Atlantic (1). They were killed in their thousands for their valuable oil and baleen (2), until commercial whaling was prohibited by the International Whaling Commission in 1935 (1).
Whilst the North Atlantic right whale is no longer hunted (1), decades of exploitation have left a tragic legacy. The small, remaining population, concentrated along the heavily industrialised coast of north-eastern America (7), is highly vulnerable to the impacts of human activities. Collision with ships is currently the most serious source of mortality threatening the North Atlantic right whale, and was the cause of 16 North Atlantic right whale deaths between 1970 and 1999. This is closely followed by the threat of entanglement in commercial fishing gear, either active gear or nets that have been lost or damaged. Known as ‘ghost gear’, this fishing equipment continues to wreak havoc on marine species, with three North Atlantic right whales known to have died from entanglement since 1970 and a further eight known to have been seriously injured, most likely with fatal consequences (2). These numbers may sound small, but in a population of just 300 or so individuals, the consequences can be enormous.
A number of other threats may also be impacting this imperilled species, including a loss of habitat due to human activity, oil spills, man-made noise which may interfere with communication, intensive commercial fishing having knock-on effects on prey availability, and global climate change (2). As the North Atlantic right whale has a relatively narrow range of prey on which it can feed, and relies on a specific combination of water currents and temperatures to create suitable feeding grounds, changes to ocean temperatures and currents caused by global climate change could have devastating affects (2) (8). Indeed, climate change may be the final factor that pushes this species over the brink to extinction (8).
Since the North Atlantic right whale was protected from hunting in 1935 by the International Whaling Commission (IWC), and also protected in Canada, which is not a member of the IWC (1), the most important conservation need for this species is the reduction, or elimination, of deaths and injuries from ship collisions and entanglement in fishing gear (3).
Both the US and Canada have developed recovery plans for this species, with the aim of addressing these issues, and a number of measures have already been implemented. These include regulations in the US to restrict the use of certain types of fishing gear in areas and times where North Atlantic right whales are common, as well as regulations that specify the distance with which a whale-watching vessel or other ship may approach a whale (1). Since 1999, a scheme has been in place in two areas in calving and summering grounds to warn vessels when there are right whales in the area, and in the Bay of Fundy, shipping lanes have been moved to divert them away from the major summer concentrations of right whales (1). As of yet, there is no data to indicate whether such measures have been successful or not (1), and recovery of this species continues to be slow, or even absent (3). If these measures have not been sufficient, the outlook for the North Atlantic right whale is grim. As it is a long lived species, extinction may not occur in the near future, but the extinction of this great whale in the next century is a very real possibility (3).
For further information on the conservation of the North Atlantic right whale and how you can help see:
New England Aquarium:
Defenders of Wildlife:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
- Amphipods: a group of small shrimp-like crustaceans that includes sandhoppers, beach hoppers, and water lice.
- Baleen: in some whales, the comb-like fibrous plates hanging from the upper jaw that are used to sieve food from sea water. These are often referred to as whalebone.
- Copepods: large and diverse group of minute marine and freshwater crustaceans belonging to the subclass Copepoda. They usually have an elongated body and a forked tail.
- Crustaceans: diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
- Dorsal fin: the unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
- Gestation: the state of being pregnant; the period from conception to birth.
- Larval: of the stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Pectoral fins: in cetaceans (whales, dolphins and porpoises), the paddle-like pair of limbs, also known as ‘flippers’, found on either side of the body and used for balance and steering.
- Planktonic: aquatic organisms that drift with water movements; may be either phytoplankton (plants), or zooplankton (animals).
- Zooplankton: Tiny aquatic animals that drift with currents or swim weakly in water.
IUCN Red List (October, 2008)
- Kenney, R.D. (2002) North Atlantic, North Pacific, and Southern Right Whales. In: Perrin, W.F., Würsig, B. and Thewissen, J.G.M. (Eds) Encyclopedia of Marine Mammals. Academic Press, London.
- National Marine Fisheries Service. (2005) Recovery Plan for the North Atlantic Right Whale (Eubalaena glacialis). National Marine Fisheries Service, Silver Spring, Maryland.
CITES (November, 2008)
- Macdonald, D.W. (2006) The Encyclopedia of Mammals. Oxford University Press, Oxford.
- Burnie, D. (2001) Animal. Dorling Kindersley, London.
- Reeves, R.R., Smith, B.D., Crespo, E.A. and Notarbartolo di Sciara, G. (2003) Dolphins, Whales and Porpoises: 2002–2010 Conservation Action Plan for the World’s Cetaceans. IUCN/SSC Cetacean Specialist Group, IUCN, Gland, Switzerland and Cambridge, UK.
- Simmonds, M.P. and Isaac, S.J. (2007) The impacts of climate change on marine mammals: early signs of significant problems. Oryx, 41(1): 19 - 26.