Marine Mammal Commission

North Pacific Right Whale

The North Pacific right whale was driven nearly to extinction by commercial whaling in the 19th century. After beginning to recover in the first half of the 20th century, most of the remaining whales were killed by illegal Soviet whaling in the 1960s. Today, there are likely fewer than 500 right whales in the entire North Pacific, with likely less than 50 in U.S. waters.

North Pacific Right Whale

North Pacific right whale. (Robert Pitman, NOAA)

Species Status

Whaling records suggest that North Pacific right whales occupied much of the northern Gulf of Alaska and the western side of the North Pacific from Kamchatka to the Sea of Japan prior to 1840 when commercial whaling began to target them. Within 10 years the species had been severely depleted throughout its range and by 1900 was near extinction. While whalers turned to other species and other parts of the world, the International Convention for the Regulation of Whaling banned the commercial hunting of right whales in the North Pacific in 1937 and the North Pacific right whale population began a slow recovery. However, illegal Soviet whaling in the 1960s killed hundreds of whales, mostly in the northern Gulf of Alaska and Bering Sea, which again pushed the species towards extinction.

Although there is a great deal of uncertainty about the number of North Pacific right whales before commercial whaling and now, there were at a minimum 10,000, and likely many more, whales distributed  across the North Pacific before whaling whereas today there are probably no more than 500.

Two populations of North Pacific right whales are now recognized, a western population offshore of Russia and Japan, and an eastern population found primarily in the eastern Bering Sea. The eastern population is known primarily from whales observed on summer-fall feeding grounds in the southeastern Bering Sea (U.S. waters). That feeding aggregation was estimated in the late 2000s to number only approximately 30 whales. In addition, a few individuals have been detected in the northern Gulf of Alaska south of Kodiak Island. Thus, the eastern population is thought to number no more than 50 whales, making it the smallest known population of large whales in the world  Researchers judged that four individuals in the southeastern Bering Sea feeding aggregation were calves or juveniles (based on size and associations), indicating that the whales were still reproducing. Genetic analyses of biopsy samples from 24 of the individuals revealed a 2:1 male to female sex ratio, suggesting that there were on the order of just 10 females remaining in the feeding aggregation at that time. The small effective population size alone may put this population at extreme risk of extinction due to effects of inbreeding and the potential for random events to affect a large portion of the population. Although right whales have continued to be detected by acoustic monitoring stations in southeastern Bering Sea, there are not any recent surveys of the feeding aggregation, which provide up-to-date information on its status.

The western population of right whales feeds during the summer in the Sea of Okhotsk, around the Commander and Kuril Islands, and off the Kamchatka Peninsula, Russia, and possibly as far south as northern Japan. Survey data on this population are limited and population size estimates are highly uncertain. The most widely accepted estimate put the size of the population in the 1990s in the low- to mid-hundreds, but probably not more than 500.

Very little is known about the movements, migration, or breeding and winter-spring calving/nursing grounds of the species. Commercial whaling data and limited survey and sightings/strandings data, suggest that they make north-south seasonal migrations, although the extent of those migrations and the winter destinations remain largely unknown. Right whales were taken by whalers and have been sighted in coastal waters on both sides of the North Pacific at lower latitudes, but so far a pattern has not emerged to suggest the location of possible winter-spring calving/nursing grounds. Acoustic monitoring has shown that at least some right whales are present in the southeastern Bering Sea from May through early December.

A few sightings of North Pacific right whales outside of the known summer-fall feeding grounds have been made in recent years that provide clues about other feeding grounds or wintering grounds. In February and June 2013, two different individuals were seen off British Columbia, and also in June an acoustic detection occurred off Washington State. Another acoustic detection was made near the Quinn Seamount in the south-central Gulf of Alaska that year. Small numbers of right whales have been seen by fishermen or whale watchers, or have been entangled or stranded, in Japan during the winter in several years in the past decade, and researchers have sighted right whales off northern Japan in the spring and summer. A young right whale was found entangled in aquaculture gear in South Korea in February 2015; much of the gear was cut off, but the whale’s fate is unknown. And, in the same month, two likely North Pacific right whales were sighted at San Miguel Island, in the Channels Islands, southern California. In October 2016, an entangled right whale was reported to have died while being disentangled in Volcano Bay, Hokkaido, Japan.

What the Commission Is Doing

For years the Marine Mammal Commission has been highlighting the North Pacific right whale as a species of extreme conservation concern, and urging the National Marine Fisheries Service (NMFS) to increase funding and efforts to improve understanding of its biology and ecology and of the threats it faces from human activities. Our current efforts focus on three goals:

  • Acquiring new evidence of the species’ occurrence outside the Bering Sea, especially evidence of migratory or other movements and the location(s) of wintering/calving grounds or important feeding grounds south of the Aleutians or in the northern Gulf of Alaska.
  • Contributing to the understanding of human-based risk factors that can be mitigated, especially when and where the whales are likely at high risk of ship strike (e.g., crossing the northern Great Circle shipping route and in Unimak Pass in Alaska’s Aleutian Islands chain) or entanglement (e.g., southeastern Bering Sea).
  • Identifying opportunities to increase funding for the conservation, research and recovery of the species.

In 2015, the Commission made two grants to NOAA’s Alaska Fisheries Science Center. One grant provided support to a ship-based, visual and passive acoustic survey of North Pacific right whales and other large whales in the Gulf of Alaska. A 21-day survey that covered 3400 nm of trackline in the Gulf of Alaska had acoustic detections of North Pacific right whales on just two days. Those detections occurred in a small area called the Barnabas Trough, just south of Kodiak Island and within the critical habitat zone for the species. The second grant supported the analysis of passive acoustic data from permanent moorings in the Aleutian Islands and Bering Sea. The analyses will be used to detect the presence of North Pacific right whales in several parts of the Bering Sea and Aleutian Islands.

Commission Reports and Publications

To date, there are no Commission reports for the North Pacific right whale.

Commission Letters

Letter Date Letter Description
June 3, 2015

Letter to U.S. Department of Transportation regarding the development of a port access route study for the Chukchi Sea, Bering Strait, and Bering Sea

April 29, 2015

Letter to NMFS with a recommendation regarding its draft 2014 North Pacific right whale stock assessment

April 3, 2014

Letter to NMFS with a recommendation regarding its draft 2013 North Pacific right whale stock assessment

March 11, 2013

Letter to NMFS providing comments and recommendations regarding the draft North Pacific right whale recovery plan

November 14, 2012

Letter to NMFS with a recommendation regarding its draft 2012 North Pacific right whale stock assessment

November 22, 2011

Letter to NMFS with a recommendation regarding its draft 2011 North Pacific right whale stock assessment

November 2, 2010

Letter to NMFS with a recommendation regarding its draft 2010 North Pacific right whale stock assessment

September 24, 2009

Letter to NMFS with a recommendation regarding its draft 2009 North Pacific right whale stock assessment

December 14, 2007

Letter to NMFS regarding its proposed rule to designate areas in the Gulf of Alaska and southeastern Bering Sea as critical habitat for the North Pacific right whale

February 22, 2007

Letter to NMFS providing advice with respect to the proposed listing of the North Pacific right whale as an endangered species under the Endangered Species Act

Learn More


Because so little is known about the distribution, movements, biology, and ecology of this species, very little is known with certainty about the threats it faces. However, there can be no doubt that its recovery, if not its very survival, will depend on successful reproduction and recruitment into the adult population for decades into the future, and this requires that threats from human activities are identified and mitigated as quickly and as thoroughly as possible. The fate of the very small number of whales in the eastern population is primarily a U.S. responsibility, and therefore it is incumbent on the federal agencies to lead efforts to meet that challenge.

North Atlantic right whales are known to be particularly susceptible to ship strikes which can cause serious injury and death. Prior to the imposition of speed limits in parts of their range along the U.S. East Coast in 2008, at least two North Atlantic right whales died per year due to ship strikes. North Pacific right whales likely migrate, as do other right whales, between high-latitude foraging grounds and calving/nursing grounds in warmer, calmer, lower-latitude waters. This means that those whales using the feeding ground in the southeastern Bering Sea must cross the Great Circle shipping routes that links North American and Asia at least twice a year. The number of crossings could be greater given that they may move back and forth between the Bering Sea and Gulf of Alaska during the summer and fall. It is likely that the whales use Unimak Pass, the route through the Aleutians that is closest to the Bering Sea feeding ground. This pass, just 11 miles wide at its narrowest point, is used routinely by ships following the northern Great Circle route. In 2012, AIS (Automatic Identification System) data revealed that there were 4,615 passages by deep-draft vessels through Unimak Pass (over 12 per day). With the increase in global commercial shipping, combined with the ongoing loss of Arctic sea ice and general expansion of human activities in the Arctic, vessel traffic through Unimak Pass can be expected to increase further.

North Atlantic right whales are also highly susceptible to entanglement in pot/trap and gillnet gear. Research has shown that 83 percent of all North Atlantic right whales photo-identified through 2009 bore scars indicative of entanglement in fishing gear. From 2000 to 2014, at least 17 whales from a population of roughly 300 to 450 are known to have died from entanglement in fishing gear. Because most deaths at sea are not detected, the actual number killed is almost certainly higher. It is reasonable to assume that North Pacific right whales are also susceptible to entanglement and that gillnet and pot/trap fisheries in the Bering Sea and Gulf of Alaska represent a threat, particularly when the fisheries operate within right whale critical habitat. None of the right whales photographed in the southeastern Bering Sea had noticeable entanglement scars, but at least two others photographed elsewhere did. As mentioned earlier, a right whale became entangled in aquaculture gear in South Korea in 2015.

The recovery plan for the species identifies several other potential threats (e.g., vessel noise, oil spills, and climate change). We can only speculate on threats faced during the winter and spring when the whales’ whereabouts are largely a mystery.

Current Conservation Efforts

In 2008, NMFS designated two areas in Alaskan waters as critical habitat for the endangered North Pacific right whale. One is in the southeastern Bering Sea where most of the eastern population apparently spends the summer and fall.  The other is south of Kodiak Island in the Gulf of Alaska where a few visual and acoustic observations have been recorded since 2000.

In June 2013, NMFS finalized the recovery plan for the North Pacific right whale. The plan assessed the status of the species, described the threats it faces, and laid out the steps needed for the species to recover. The primary focus of the recovery plan is to obtain information on seasonal movements, habitat use, distribution, population size, and trends. In addition, the recovery plan highlights the need for better understanding of the threats affecting the species. However, since its publication, the plan has not been implemented and funding allocated toward promoting the species’ recovery has been far from sufficient, despite the plan calling for expenditures of over a million dollars each year.

The Future/Next Steps

Research is critically needed to understand where North Pacific right whales are located throughout the year, which habitats they use in each season and location, and which human activities and impacts pose the greatest threats to these animals. The eastern population is the responsibility of the United States.

Additional Resources

General Information

NMFS North Pacific right whale species page

International Union for Conservation of Nature (IUCN) North Pacific right whale page

North Pacific right whale – Wikipedia page

Selected Peer-Reviewed Publications

Conservation status of North Pacific right whales. Robert L. Brownell, Jr., et al. 2001. Journal of Cetacean Research and Management (special issue) 2:269-286

Distribution of North Pacific right whales (Eubalaena japonica) as shown by 19th and 20th century whaling catch and sighting records. Phillip J. Clapham et al. 2004. Journal of Cetacean Research and Management 6(1):1-6

The biogeography of the North Pacific right whale (Eubalaena japonica). Edward J. Gregr and Kenneth O. Coyle. 2009. Progress in Oceanography 80(2009):188-198

Soviet catches of right whales Eubalaena japonica and bowhead whales Balaena mysticetus in the North Pacific Ocean and the Okhotsk Sea. Yulia V. Ivashchenko and Phillip J. Clapham. 2012. Endangered Species Research 18:201-217

Historical distribution of right whales in the North Pacific. Elizabeth Josephson et al. 2008. Fish and Fisheries 9:155-168

Genetic analysis of right whales in the eastern North Pacific confirms severe extirpation risk. R.G. LeDuc et al. 2012. Endangered Species Research 18:163-167 

The world’s smallest whale population. Paul R. Wade et al. 2011. Biology Letters 7(1):83-85

Relevant Documents

NMFS 2014 North Pacific right whale stock assessment

NMFS 2013 Final Recovery Plan for the North Pacific Right Whale