North Pacific right whale (Eubalaena japonica) COSEWIC assessment and status report: chapter 3

Species Information

Name and classification

The taxonomic status of right whales (genus Eubalaena) worldwide has been the subject of mild controversy for over twenty years. Most authors agreed that there should be two species, E.glacialis for the North Atlantic and North Pacific populations (so-called northern right whales), and E. australis for all Southern Hemisphere populations (southern right whales), with the North Atlantic and North Pacific forms sometimes considered subspecies, E. glacialis glacialis and E. g. japonica, respectively (see Schevill 1986). Rice (1998) lumped right whales and bowheads (Balaena mysticetus) within the genus Balaena, and combined all right whales in a single species, B glacialis, with two subspecies, B. g. glacialis (North Atlantic and North Pacific), and B. g. australis (Southern Hemisphere).  However, a 1998 International Whaling Commission (IWC) workshop recommended retaining Eubalaena (the right whales) as a separate genus, and noted that the IWC Scientific Committee would consider changing taxonomic status only on the basis of published papers (IWC 2001a). Rosenbaum et al. (2000) reviewed genetic data on right whales worldwide and concluded that three species should be recognized. The IWC Scientific Committee, after considering genetic and morphological data, decided at its 2000 annual meeting to accept Rosenbaum et al.’s analysis and proposed nomenclature. It was agreed to retain the generic name Eubalaena for right whales, and to recognize three species, E. japonica in the North Pacific, E. glacialis in the North Atlantic, and E. australis in the southern hemisphere (IWC 2001a).

Right whales were once common in temperate latitudes of all of the world’s oceans. The warm tropical belts in the Atlantic and Pacific Oceans naturally separated the northern and southern populations. In addition, the animals in the North Atlantic and North Pacific were isolated from one another by the continents of North America and Eurasia and the Arctic Ocean.

Two species of right whale occur in Canadian waters, E. japonica in the Pacific (Figure 1) and E. glacialis in the Atlantic. This report considers the status of E. japonica in the eastern North Pacific only; no subspecies are recognized. The common name in English is the eastern North Pacific right whale. The two common names used in French in Canada are baleine noire and baleine franche. The Nuu-chah-nulth named the right whale kw’utskii, meaning “edible blue mussels on head” (Webster 1982).

Figure 1. Historic distribution of Right Whales along the Pacific Coast of Canada. Prepared by J. Beaudin Ring, September, 2002.

Figure 1. Historic distribution of Right Whales along the Pacific Coast of Canada.

Map is mercator projection (Central Meridian = -62.00). Coastal coverages extracted from Woods Hole Coastal and Marine Science Center. Sighting data based on Right Whale Consortium database.

Description

The North Pacific right whale, Eubalaena japonica (Lacepede 1818; Rosenbaum et al. 2000), is a large, robust baleen whale (see cover illustration). Adults can reach up to 18 metres in length, and may weigh over 100 metric tons (Kenney 2001). Females are larger than males, and newborns are 4.5 to 6 metres long at birth (Kenney 2001). Right whales are distinguished by a stocky body, black colouration, sometimes with white patches on their ventral surface, lack of a dorsal fin, a highly-arched narrow rostrum

(about ¼ of the body length), strongly-bowed lower jaw, and callosities on the head region (Kenney 2001). These callosities are irregular patches of thickened, keratinized columnar epithelial tissue (Kenney 2001). Callosities are found on the rostrum, behind the blowholes, over the eyes, on the corners of the chin, and variably along the lower lip and jaw lines. The arrangement of callosities is unique to each right whale and is used for individual recognition (Kraus et al. 1986, Hamilton and Martin 1999). The callosity patches appear white, yellowish or orange because of infestations of Cyamid spp. crustaceans called whale lice. Two rows of long (up to about 2.5 m in length), dark baleen plates hang from the upper jaw, with about 225 plates on each side. The tail is broad (up to 6 m tip to tip), deeply notched, and all black with a smooth trailing edge. They have a distinctly V-shaped blow, upwards of 7 metres in height. No significant morphological differences have been documented between right whales in the North Pacific, North Atlantic and Southern Oceans, but North Pacific animals yielded much larger amounts of oil and baleen (Best 1987).

Nationally significant populations

The status of the E. japonica is considered the same throughout its range in the eastern North Pacific.

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