Northern right whale  (Eubalaena glacialis)

The northern right whale is the most endangered of the great whales (8). This species received its name from whalers who considered it to be the 'right' whale to hunt; they swim slowly, float when dead and contain high quantities of oil and baleen (3). The northern right whale is a bulky species, black in colour with patches of white on the chin and underside, and a large head relative to the body. A number of 'callosities' (thickened rough patches of skin) occur at various points on the body, and these are covered in whale lice (Cyamus spp.) so that they appear whitish yellow (9). These callosities tend to be larger in males than females, and on the head and jaw the pattern is unique, allowing individuals to be identified (3). Females are larger than males, and juveniles are usually bluish in colour, becoming darker as they age (4). From a distance the species can be identified by the characteristic v-shaped blow, which can reach up to 5 m in height (6).

The majority of northern right whales are found in the western North Atlantic, off the coasts of Canada and North America, with a worldwide population estimated at less than 320 (8). Only a few individuals are thought to remain in the eastern North Atlantic and North Pacific Oceans (10).

Inhabits temperate and sub-polar waters and calves in shallow waters close to the shore (6). Poorly understood migrations take place between northern feeding grounds and southern calving sites (3).

The callosities on the body are infested with parasitic whale lice. The function of these patches is unknown, but one theory is that males use them in competing for females (3). This whale produces a variety of low-frequency sounds; contact calls between individuals separated by a large distance and calls that females use to attract mates have both been studied (3). The northern right whale feeds by filtering small crustaceans from the water using the baleen plates. Individuals swim through a swarm of prey with the head slightly above water and the mouth open. When the prey has been filtered through the baleen the water is driven out (7). This species can dive to depths of 50 m for 15 - 20 minutes (4). Females give birth every 2 to 4 years (7), between February and April after a gestation period of about a year (4). Infants measure around 5.5 m at birth, and are nursed for 6 to 7 months (4), they stay close to their mother, who may occasionally roll onto her back and hold the calf in her flippers (7). This species tends to occur in small groups of around six individuals. In winter, individuals migrate to the breeding and mating grounds in warmer seas to the south, and return to the colder food-rich feeding grounds in summer (4), but few precise details of the migratory behaviour of the species are known (5).

The main threat to the northern right whale has been hunting, which was once a lucrative industry. Whales were hunted for oil and 'whalebone' (from the baleen), which was used in whips, umbrellas, corsets and skirts (4). This species was almost hunted to extinction by 1800; after years of protection the population still numbers less than a few hundred amd the species remains at risk (3). Their preference for coastal waters renders these whales particularly vulnerable to mortality caused by fishing gear and collisions with ships.

The northern right whale has been protected internationally since 1935 (5), but has not recovered from earlier persecution (6). The United States has taken measures following the production of a Recovery Plan, these include fishing area closures, and modifications to fishing gear (6). The southeast of the United States, Cape Cod Bay and the Great South Channel have been designated as critical right whale habitat, and a number of key areas off Canada are now seasonal conservation areas (6). Furthermore a 70,000 square mile area of the Bering Sea has recently been identified as critical habitat in the North Pacific, and may receive protection as a result (5).

Whale and Dolphin Conservation Society (WDCS)
http://www.wdcs.org/dan/publishing.nsf/allweb/4354AD469D068671802569660054540D

The Smithsonian Institution's North American Mammals website:
http://www.mnh2.si.edu/education/mna/image_info.cfm?species_id=90

Authenticated (25/11/02) by WDCS, The Whale and Dolphin Conservation Society.
http://www.wdcs.org