Eastern and Western Populations
North Pacific right whales are considered to exist in two populations based on geographic distribution: eastern and western North Pacific. The range of eastern North Pacific right whales is believed to encompass the west coast of North America, from the Bering Sea and Gulf of Alaska down to Baja, Mexico and as far west as Hawai’i. The western population ranges from near the Commander Islands off the coast of Kamchatka, along the Kuril Islands, and in the Sea of Okhotsk south to Japan.
There are few reliable estimates of the current number of North Pacific right whales, but it is thought to be in the low 100s. There may have been as many as 37,000 North Pacific right whales before commercial whaling drastically reduced populations in the 19th century.
Eastern Population
The eastern population of North Pacific right whales is one of the smallest large whale populations in U.S. waters. The eastern population is estimated to have fewer than 50 animals. After being hunted extensively in the nineteenth century, they were protected by international treaties in the 1930s and 1940s. Despite these protections, illegal Soviet whaling in U.S. waters during the 1960s decimated the already reduced population, and there have been no signs of recovery since. In fact, for many years, the whales were so rarely seen that sightings of individuals warranted publication.
Since 1996, North Pacific right whales have been found repeatedly in or near a small area of the southeastern Bering Sea, which was designated as critical habitat under the Endangered Species Act in 2008. Even though there have been substantial research efforts in this area in certain years, the entire photographic identification catalog of Bering Sea right whales (as of 2025) only includes 31 confirmed unique individuals, and the genetics archive contains only 32 individuals.
The population in the Bering Sea is thought to number only about 28 whales, with 20 males and eight females. The small number of females is of great concern, and relatively few calves and juveniles have been seen in the last few decades (only five since 2002). Sightings in the Gulf of Alaska are even more rare; several surveys in the Gulf of Alaska have acoustically detected right whales without seeing them. Interestingly, there has never been a photographic match between the Gulf of Alaska and the Bering Sea.
Dedicated aerial surveys, ship surveys, and satellite tagging research on North Pacific right whales in the Bering Sea have not been conducted since 2010 due to a lack of funding. The only current field research on North Pacific right whales consists of a series of acoustic recorders in the Gulf of Alaska and the Bering Sea that can detect their occurrence, and NOAA Fisheries scientists opportunistically joining other marine mammal surveys.
Western Population
The area inhabited by North Pacific right whales from the western stock includes Russian and Japanese territorial and exclusive economic zone waters and some international waters, even in the center of the Sea of Okhotsk. As a result, surveys for whales have generally not been comprehensive. Therefore, information on distribution and abundance from the western stock is limited, and its status is currently unknown.
The only existing estimate of the western North Pacific right whale population comes from three Japanese minke whale sighting surveys in the Sea of Okhotsk conducted between 1989 and 1992. This estimate was 922 animals; however, biases were identified in the survey methodology, and the estimate should be considered unreliable given its low precision. The population estimate for the western stock is likely in the low hundreds.
Most sightings of western North Pacific right whales have occurred in waters off Russia and Japan. Most summer sightings have been in the offshore waters of Kamchatka and the Kuril Islands, while most winter and early spring sightings were off Japan. In the last five years, there have been at least nine reported sightings of western North Pacific right whales, in addition to two dead stranded whales found in Hokkaido, Japan (2023) and Kamchatka (2025). Reports have included numerous behaviors, such as breaching, traveling, and feeding, and some sightings had more than one individual present.
