North Pacific Right Whale

Species Status

Abundance and Trends

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 presumably many more, whales distributed across the North Pacific before whaling. Today, there are likely no more than 500 whales.

Two populations of North Pacific right whales are recognized, a western population currently found offshore of Russia and Japan, and an eastern population currently found primarily in the eastern Bering Sea (U.S. waters). The most recent population estimate for the eastern population of whales, based on a 2010 study of whales observed on their summer-fall feeding grounds in the southeastern Bering Sea, was approximately 31 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. 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.

The last population estimate for the western stock, based on survey data from 1989 to 1992, suggested approximately 900 individuals, with confidence intervals ranging from 404 to 2,108. However, no current reliable population estimates are available for the western stock.

Distribution

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 data, suggest that they make north-south seasonal migrations, although the extent of those migrations and the winter destinations remain largely unknown.

The summer range of the eastern population includes the Gulf of Alaska and the Bering Sea, with the population primarily known from whales observed on summer-fall feeding grounds in the southeastern Bering Sea. A recent compilation of eastern North Pacific right whale sightings from 2006 to 2023 showed sightings primarily in the central North Pacific and Bering Sea. Sightings have ranged from as far south as central Baja California and Hawaii to the northern waters of the Bering Sea and the Sea of Okhotsk in the summer. Feeding during those sightings was observed throughout the range at different times of year, although concentrated in their Alaska feeding grounds. The study included sightings from the 2017 International Whaling Commission’s Pacific Ocean Whale and Ecosystem Research (IWC-POWER) cruise, which documented 12 unique right whales in the southeastern Bering Sea, over half of which were found east of the critical habitat designated in the 2000s. One individual may have been a juvenile, suggesting ongoing successful reproduction in this very small population. The 2023 IWC-POWER cruise had four additional North Pacific right whale sightings in the Gulf of Alaska.

Due to their small population size and limited sightings data, acoustic monitoring has been implemented in the Bering Sea and northern Gulf of Alaska to detect the presence of North Pacific right whales since the 2000s. Acoustic monitoring has shown that at least some right whales are present in the southeastern Bering Sea from May through early December and in the northern Bering Sea during summer, fall, and winter, which has been confirmed by at least one visual sighting.  Acoustic detections in eastern passes through the Aleutian Islands throughout the year may suggest that they were feeding or transiting in the area, possibly while moving or migrating between the Bering Sea and North Pacific.

The western population of North Pacific 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. A 2021 publication documented 60 sightings 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. Whales from the western population have been sighted outside of their summer feeding grounds, with occasional reports of sightings in winter and spring, primarily along the coast of Japan and the western North Pacific.

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. 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 funded two grants to National Marine Fisheries Service’s (NMFS) 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, and the second grant supported the analysis of passive acoustic data from permanent moorings in the Aleutian Islands and Bering Sea. In 2016, the Commission provided funding to support a NMFS Saildrone passive acoustic survey of portions of the Bering Sea; results were published in the report available here. Research is on-going on a project funded in 2021 using samples from archived museum research specimen’s baleen to explore migratory patterns and overwintering areas of North Pacific right whales.
In 2023, the Commission co-hosted a Whales on the Brink scientific symposium with NMFS and the Smithsonian National Museum of Natural History that featured the North Pacific right whale.

Commission Reports and Publications

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

Commission Letters

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Threats

Due to the limited understanding of North Pacific right whale distribution, movements, biology, and ecology, the threats this species faces remain largely uncertain. 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.

Vessel strikes can cause serious injury or death to North Pacific right whales. The closely related North Atlantic right whales are known to be particularly susceptible to vessel strikes, and North Pacific right whales are likely similarly at risk. North Pacific right whales presumably 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 America 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 recent years, fishermen observed North Pacific right whales further north, near the Bering Strait, another narrow body of water, where they are at increased risk of being hit by ships. 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 this region can be expected to increase further.

North Pacific right whales are also susceptible to entanglement in fishing gear and marine debris, with gillnet and pot/trap fisheries in the Bering Sea and Gulf of Alaska posing a threat, particularly when these fisheries operate within the whales’ critical habitat. None of the right whales photographed in the southeastern Bering Sea had noticeable entanglement scars, but at least two others photographed in NMFS’s North Pacific right whale photo-identification catalog did. Additionally, in 2015, a young right whale was found entangled in aquaculture gear in South Korea, and in 2016, an entangled right whale was reported to have died while being disentangled in Volcano Bay, Hokkaido, Japan. Although entanglements of North Pacific right whales are rarely documented, entanglement in fishing gear is a major source of mortality for the North Atlantic right whales. Additionally, documented entanglements of Western Arctic bowhead whales in areas partially overlapping with the North Pacific right whale range suggest that this threat is present, despite limited documentation.

Climate change is likely to pose significant threats to the North Pacific right whale population, as their range within the North Pacific is already experiencing climate-related impacts, and their small population size exacerbates their vulnerability. The species’ dependence on large aggregations of zooplankton for feeding makes it particularly susceptible to changes in prey abundance and distribution, which could result from changes in oceanographic conditions. Declines in zooplankton availability could cause nutritional stress, reduced reproduction, lower survival rates, and disruptions to migration patterns.

NMFS’s recovery plan for the North Pacific right whale expands on these threats and identifies several others, including vessel noise and oil spills. We can only speculate on threats faced during the winter and spring when the whales’ whereabouts are largely a mystery.

Current Conservation Efforts

NMFS listed the North Pacific right whale as endangered under the Endangered Species Act (ESA) in 1970. 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.

In 2008, NMFS designated two areas in Alaskan waters as critical habitat under the ESA for the North Pacific right whale. One is in the southeastern Bering Sea, where most of the eastern population 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 September 2023, NMFS announced a 12-month determination on a petition to revise the critical habitat designation based on updated scientific data.

In February 2024, NMFS completed a five-year status review that the ESA requires for listed species, concluding that the North Pacific right whale should retain its status as endangered. The review emphasized the critical need to further understand the species’ distribution and seasonal patterns, particularly for wintering areas, assessing overlap with and impacts from shipping and fishing activities, and continuing to identify emerging threats.