The western Pacific population of gray whale (Esrichtiius robustus) is one of only two surviving populations of this species in the world. Although historically both populations were brought near to extinction by commercial whaling, the eastern Pacific population, which migrates annually between Mexico and Alaska, has recovered substantially and now numbers about 20,000 individuals. By comparison, the western Pacific population, or western gray whale is estimated at about 150 individuals, including perhaps some 36 reproductive females in 2012. They are believed to migrate between eastern Russia and China, however the 2010-2011 satellite tagging of whales off Sakhalin revelead some new insights in their migration.
IUCN has been concerned by the status of western gray whales for many years. Through its Species Survival Commission (SSC), IUCN has collaborated with a joint USA-Russian research project launched in the mid-1990s to examine the conservation status, behavior, and distribution of the whales as well as their associated threats. As a result of this research project, in 2003 the western gray whale population was listed in the IUCN Red List of Threatened Species™ as critically endangered.
The population has also been the focus of international concern, including the International Whaling Commission (IWC), which calls year after year for urgent measures to protect the population, and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) which has listed the western gray whale as a species threatened with extinction.