North Pacific Right Whale

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 currently found offshore of Russia and Japan, and an eastern population currently 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 approximately only 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 considered by experts to number no more than 50 whales, making it one of the smallest known populations of large whales in the world. No photo-id matches have been made between the animals in the Bering Sea and those in the Gulf of Alaska, opening the possibility that they are separate sub-populations. Researchers judged that four of the individuals in the documented southeastern Bering Sea feeding aggregation in the 2000s 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 roughly 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. Acoustic monitoring has continued to detect the presence of right whales in the Bering Sea and some surrounding areas since the 2000s. In the last several years, scientific surveys have searched for North Pacific right whales in Alaskan waters but have found few individuals and none far outside previously known areas of occupation.

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. 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. A recent Japanese publication documents 60 sightings of North Pacific right whales made on research cruises between 1994 and 2016, involving 83 individuals and 10 calves.  The whales were concentrated in southern half of the Sea of Okhotsk, and far offshore southeast of the Kamchatka Peninsula.

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 to date 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. In addition, the monitoring has shown that North Pacific right whales occur in the northern Bering Sea during summer, fall, and winter, which has been confirmed by at least one visual sighting. In recent years, North Pacific right whales have been detected as far north as the Bering Strait, which may reflect a response to ocean warming or to oscillations in oceanographic conditions that influence the availability of prey affected by water temperature. Finally, right whales have been detected acoustically in two eastern passes through the Aleutian Islands throughout the year suggesting that they were feeding or transiting there, perhaps while moving or migrating, between the Bering Sea and North Pacific.

Ship-based, visual and passive acoustic marine mammal surveys conducted by the National Marine Fisheries Service in the Gulf of Alaska in 2013, 2015 and 2021 have detected small numbers of North Pacific right whales in the Gulf of Alaska in a small area called the Barnabas Trough, just south of Kodiak Island and within the critical habitat zone for the species. An international, ship-board, and passive acoustic survey in the Bering Sea during summer, 2017documented the presence of 12 unique right whales in southeastern Bering Sea, over half of which were found east of the critical habitat that was designated following the surveys in the 2000s. One individual may have been a juvenile, suggesting ongoing successful reproduction in this very small population.

A few sightings of North Pacific right whales outside of the known summer-fall feeding grounds have been made in recent years in both the western and eastern North Pacific, which could provide clues about other feeding grounds or wintering grounds. In the last decade, there have been a handful of sightings or acoustic detections of single individuals in the northeast North Pacific: in 2013, 2018, 2020 and 2021 off British Columbia or Washington State and in 2013 near the Quinn Seamount. In 2016 and 2017, there were three sightings of 1-2 individuals in Southern California. 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 15 years, and researchers have sighted right whales off northern Japan in the spring and summer. In the same region, 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. In October 2016, an entangled right whale was reported to have died while being disentangled in Volcano Bay, Hokkaido, Japan. In August 2018, a right whale was sighted off the Chukotka Peninsula, Russia, well north of almost all other sightings, and genetically linked to whales in the eastern population. In February 2022, a unique sighting by fishermen discovered at least two right whale foraging in the Bering Sea northeast of Unimak Pass. Although there have been acoustic detections of right whales in the Bering Sea during winter, this was the first visual sighting and confirmation that they are feeding in winter.

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; research results from this study were published in 2019 (see Selected Peer-Reviewed Publications in Additional Resources). 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. Research results from this study were published in scientific papers in 2018 and 2019 (see Selected Peer-Reviewed Publications in Additional Resources). In 2016, the Commission provided funding to support NOAA Fisheries’ Saildrone passive acoustic survey of portions of the Bering Sea; results were published in the report available here. See “Selected Peer-Reviewed Publications” in Additional Resources section for links to the publications mentioned here. Research is on-going on a project funded in 2021 using samples from archived museum research specimens baleen to explore migratory patterns and overwintering areas of North Pacific right whales.

Commission Reports and Publications

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

Commission Letters

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Threats

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 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 the responsibility of the U.S. federal government.

The closely related 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, at least twice a year, the Great Circle shipping routes that link North American and Asia. The number of crossings could be greater given that they may move back and forth between feeding areas in 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. In the last five years, North Pacific right whales have been seen further north, including in the Bering Strait, another narrow body of water, where they are at increased risk of being hit by ships.

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 elsewhere on this page, a right whale became entangled in aquaculture gear in South Korea in 2015.

Research published in March 2020 estimated the vulnerability of marine mammals to global warming and found the North Pacific right whale to be one of the most vulnerable species in the world.

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.

Currently, the NOAA Fisheries is conducting a five-year review of the ESA status of North Pacific right whales. The Commission commented that it “is not a aware of any evidence that might suggest the status has changed since 2012.”

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.