Eubalaena japonica (Northeast Pacific subpopulation) 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Cetartiodactyla Balaenidae

Scientific Name: Eubalaena japonica (Northeast Pacific subpopulation)
Parent Species:
Common Name(s):
English North Pacific Right Whale Northeast Pacific Subpopulation
Taxonomic Notes: This is a subpopulation of Eubalaena japonica (Lacépède, 1818).

Assessment Information [top]

Red List Category & Criteria: Critically Endangered D ver 3.1
Year Published: 2018
Date Assessed: 2017-12-18
Assessor(s): Cooke, J.G. & Clapham, P.J.
Reviewer(s): Reeves, R. & Zerbini, A.N.
Contributor(s): Morris, E.
Facilitator/Compiler(s): Lowry, L.
Although there is no estimate of abundance for Right Whales for the entire eastern North Pacific, Wade et al. (2011) estimated that there were only about 30 individuals in the eastern Bering Sea. This, and the paucity of sightings throughout the region generally, make it very probable that the number of mature individuals is below 50 individuals which qualifies the subpopulation for IUCN Red List category Critically Endangered. In addition, there is concern about the paucity of sightings of calves.
Previously published Red List assessments:

Geographic Range [top]

Range Description:

Prior to the onset of commercial whaling in the 1830s, Right Whales were widely distributed across the North Pacific (Scarff 1986, Clapham et al. 2004, Shelden et al. 2005). In the eastern North Pacific, the waters adjacent to the Aleutian Islands and much of the Bering Sea below 60oN were major feeding grounds during spring, summer, and autumn, as was virtually the entire Gulf of Alaska. Neither the historical nor the present-day breeding/calving grounds for this subpopulation have been identified.

In recent decades, most sightings as well as illegal Soviet catches (see below) have been in the southeastern Bering Sea and the western Gulf of Alaska (shelf and slope waters south of Kodiak Island). Acoustic detections of Right Whale calls have been made in both areas using autonomous recording packages deployed for extended periods (Moore et al. 2006, Wright and Clapham 2017). They confirm the consistent presence of Right Whales in the southeastern Bering Sea from May into November, while the acoustic evidence for presence in winter months is inconclusive. There have been very few Right Whale sightings in the Gulf of Alaska in recent years despite the fact that the species once occurred widely across this region. A vessel-based survey off Kodiak in the summer of 2015 failed to observe any Right Whales, although a few acoustic detections were made (Rone et al. 2016).

Seasonal movements are evident in sighting and catch data from the 20th century, with a general northward migration into the Gulf of Alaska and Bering Sea in spring and summer, and a gradual movement away from these areas in autumn (Clapham et al. 2004, Shelden et al. 2005). There are very few records of Right Whales anywhere in the North Pacific in winter.

In general, the majority of Right Whale sightings (historically and in recent times) in the eastern North Pacific have occurred from about 40º to 60º N. There are historical records from north of 60º N, but they are rare and many are likely to be misidentified Bowhead Whales (Balaena mysticetus). Right Whales have on rare occasions been recorded off California and Mexico, as well as off Hawaii. However, as noted by Brownell et al. (2001), there is no evidence that either Hawaii or the western coast of North America from Washington State to Baja California has ever been important habitat for Right Whales.

Two separate sightings of Right Whales were made in 2013 off the coast of British Columbia, the first evidence of this species in Canadian waters in 62 years (Ford et al. 2016). One of the individuals exhibited a severe but healed injury that was likely from entanglement. Two Right Whale calls were detected off the coast of Washington State in June 2013 (Širović et al. 2015).

Countries occurrence:
Canada (British Columbia); Mexico (Baja California); United States (Alaska, California, Hawaiian Is., Washington)
FAO Marine Fishing Areas:
Pacific – northeast; Pacific – eastern central
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Range Map:Click here to open the map viewer and explore range.

Population [top]


As noted above, Right Whales in the eastern North Pacific are considered to be separate from those in the west on the basis of distinct catch and recovery histories (Brownell et al. 2001, IWC 2001). The Right Whale population throughout the North Pacific is only a small fraction of what it was prior to 19th century whaling. A preliminary estimate of 26,500-37,000 animals taken (including struck and lost) throughout the entire North Pacific during the period 1839-1909 was given by Scarff (2001), of which 21,000-30,000 were taken during 1840-49 alone.

In the eastern North Pacific between 1941 and 1964, there were 598 sightings of Right Whales; in contrast, in the period 1965-1999 there was a total of only 82 sightings in this region (Brownell et al. 2001). The dramatic decrease was due to illegal Soviet catches, primarily in the Bering Sea and Gulf of Alaska, mainly in the period 1962-67; in total, 516 Right Whales are known to have been killed by the former USSR in the eastern North Pacific (Ivashchenko and Clapham 2012, updated in Ivashchenko et al. 2017). Given the paucity of sightings in subsequent years, the Soviet catches may well have accounted for the bulk of the remaining animals in this subpopulation. The few observed in the eastern North Pacific today are often alone and are scattered in their distribution. The only exception is an area of the southeastern Bering Sea where small groups of Right Whales have been seen in several successive years (LeDuc et al. 2001). In 2004, a sighting of at least 17 individuals in that area represented the largest group observed since the Soviet catches of the 1960s (Wade et al. 2006). Wade et al. (2011) used photo-identification and genetic mark-recapture data to estimate the population at about 30 animals. While this may represent a subpopulation that preferentially uses the Bering Sea, the paucity of sightings generally suggests that Right Whales in the eastern North Pacific number only in the tens (Brownell et al. 2001). Furthermore, the reproductive rate appears to be low as there have been only three observations of calves since directed survey effort began in 1998 (Waite et al. 2003, Wade et al. 2006).

LeDuc et al. (2012) analyzed 49 biopsy samples from Right Whales in the eastern (48) and western (1) North Pacific and found 24 individuals with 7 mitochondrial haplotypes. They noted that the population appears to have lost some genetic diversity, though not to the degree of North Atlantic Right Whales, and that males outnumbered females 2 to 1. A comparison of the eastern Pacific samples to a single Russian sample suggested that the two sub-populations are isolated to some degree. The effective population size for the eastern North Pacific was calculated to be 11.6 (95% confidence interval 2.9-75.0), based on the estimated linkage disequilibrium.

Because of the small number of sightings, no attempt has been made to estimate the population trend in any part of the range.

Current Population Trend:Unknown
Additional data:
Number of mature individuals:10-20Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:Unknown

Habitat and Ecology [top]

Habitat and Ecology:

Little is known about habitat use by Right Whales in the eastern North Pacific. Gregr and Coyle (2009) attempted to clarify the biophysical processes underlying Right Whale feeding area distribution, and advanced some hypotheses regarding the drivers of this distribution, but to date these remain largely untested because of lack of data. Monsarrat et al. (2016) fitted historical North Pacific Right Whale catch data to environmental covariates such as depth, surface temperature, mixing layer depth, and distance offshore, as part of an exercise to characterize Right Whale habitat generally.

The rarity of coastal records in winter in either historical or recent times suggests that the North Pacific Right Whale's breeding grounds (areas used for mating, calving, and nursing) might have been offshore (Clapham et al. 2004). This is in contrast to Southern and North Atlantic Right Whales, both of which form inshore wintering concentrations. There is clearly some migration northward in summer and southward in winter (Clapham et al. 2004), but the location of the wintering grounds is unknown. Historical catches show that in summer the population occurred mainly on feeding grounds in the Bering Sea and Gulf of Alaska. Data on food habits are sparse, but suggest that Right Whales in the eastern North Pacific feed primarily on copepods of the genera Calanus and Neocalanus (Shelden et al. 2005). Primary habitat today includes core areas of the southeastern Bering Sea and an area off eastern Kodiak Island, which were also significant parts of the range in the past (Zerbini et al. 2015).

Satellite telemetry and acoustic data indicate the importance of the middle shelf in the southeastern Bering Sea as foraging habitat, and peaks in Right Whale call detections and in abundance of the copepod Calanus marshallae directly coincide (Baumgartner et al. 2013).

Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):23
Movement patterns:Full Migrant

Use and Trade [top]

Use and Trade: Past hunting and trade were the cause of the severe reduction in numbers of this formerly abundant species. Although legally protected internationally since 1935, illegal catches continued until 1967.

Threats [top]

Major Threat(s):

There is currently no evidence of human-related mortality or serious injury (i.e. injury likely to prove lethal), but in view of the remoteness of the subpopulation’s habitat, most deaths and injuries would likely pass unrecorded.

This subpopulation is potentially subject to entanglements in fishing gear, disturbance by vessels and other noise sources, ship strikes, and contaminants (including those related to offshore hydrocarbon development and transport). The continuing loss of sea ice in the Arctic is likely to result in a significant increase in trans-polar vessel traffic through Right Whale habitat in the Bering Sea and perhaps elsewhere (Reeves et al. 2014).

As compared with the intensively studied North Atlantic Right Whale, the more offshore and remote distribution of the North Pacific Right Whale may be an advantage in terms of less frequent and intensive exposure to human activities, but the disadvantage is that any impacts of such activities that do occur are much less likely to be detected and their consequences would be harder to ascertain and evaluate. The density of fishing gear in the Bering Sea and Gulf of Alaska is a fraction of that on the eastern coast of North America where North Atlantic Right Whales are frequently entangled, and analysis of photographs suggests a low frequency of entanglement scarring in eastern North Pacific animals relative to their North Atlantic congeners. Nonetheless, as noted above, the lack of sighting effort minimizes the probability that any injury or death of a Right Whale in the eastern North Pacific will be detected.

Conservation Actions [top]

Conservation Actions:

North Pacific Right Whales were legally protected from commercial whaling through international agreements in the 1930s and 1940s, but this has been fully respected in practice only since the 1970s. A Recovery Plan has been developed by the U.S. National Marine Fisheries Service, but to date the only conservation measure undertaken has been the designation in 2006 of two areas of Critical Habitat (the southeastern Bering Sea and a small region off eastern Kodiak Island) under the U.S. Endangered Species Act, which lists Right Whales as endangered.

The species is listed in Appendix I of both the Convention on International Trade in Endangered Species and the Convention on the Conservation of Migratory Species of Wild Animals.

Citation: Cooke, J.G. & Clapham, P.J. 2018. Eubalaena japonica (Northeast Pacific subpopulation). The IUCN Red List of Threatened Species 2018: e.T133706A50385246. . Downloaded on 22 September 2018.
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