Western Gray Whale Population Status (last updated Nov-2012)
The conventional assumption in cetacean science for the last 50-plus years has been that there are two extant geographical populations of gray whales (Eschrichtius robustus), one in the eastern Pacific that migrates annually between Mexico and the Chukchi Sea and one in the west that migrates between the South China Sea and eastern Russia (mainly the Sea of Okhotsk). 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. By comparison, the population in the west has been estimated to number only about 150, including perhaps 30-35 reproductive females. In 2003, the western population was redlisted as Critically Endangered.
Starting in 2010, satellite tagging of gray whales considered to belong to the western population was carried out at Sakhalin Island, eastern Russia. Unexpectedly, the few whales successfully tagged and tracked so far have all migrated towards the east, and the two that were tracked the longest became part of the near-shore fall and spring streams of gray whales migrating between Alaska and Mexico. More satellite tagging in eastern Russia is planned in coming years, and it is clear that the previous paradigm of gray whale population structure needs rethinking.
Gray whales face a number of potential hazards throughout their range, including ship strikes, underwater noise, entanglements in fishing gear, and modification or degradation of their habitat by human activities. Particular concerns have been raised about the potential impacts of offshore oil and gas development on and near the prime gray whale feeding areas off Sakhalin. Petroleum exploration in marine waters around Sakhalin Island began in the 1990s and offshore production started in 1999. Platforms, pipelines and other types of infrastructure continue to proliferate in the region.
Western Gray Whale Advisory Panel (WGWAP)
Since 2004, IUCN has worked with Sakhalin Energy, operator of the huge Sakhalin II project close to the near-shore Sakhalin feeding area, to help that company minimize risks to the whales and habitat. In 2006, as part of this initiative, IUCN created a panel of independent scientists – the Western Gray Whale Advisory Panel (WGWAP) – which provides scientific advice and recommendations on the company’s operations and mitigation measures. The panel, chaired by Randall Reeves, consists of scientists from a range of scientific disciplines and includes several other current CSG members: Bob Brownell, Justin Cooke, Greg Donovan and Doug Nowacek.
Rangewide Conservation Initiative
The remit of the WGWAP is limited largely to oil and gas activities on the Sakhalin shelf. Particularly in light of the deaths of gray whales in fishing gear off Japan, IUCN widened its conservation initiative to encompass other areas and other types of human activity, besides oil and gas development in Russia, that threaten gray whales in Asian waters.
The above four-panel map figure (click here to view in detail) represents an attempt to outline the distribution of gray whales in the North Pacific on a seasonal basis: the summer feeding period (a), the period of southward migration (and breeding) in late autumn (b), the winter calving, early calf rearing and fasting season (c), and the period of northward migration in spring (d). The figure was prepared in October 2016 by a small group of experts consisting of Aimee Lang, David Weller, Greg Donovan, Randall Reeves and John Ford. The figure is posted on this website as a working draft with the expectation that it would be improved and regularly updated by incorporating suggestions from experts.
For details and publications on IUCN’s Western Gray Whale Conservation Initiative go to www.iucn.org/wgwap/
The above provides a background to the gray whale and its conservation. The CSG posts news items and updates about conservation of the gray whale and these can be found on our News page or at the following links:
April 2015- Young Gray Whale Sighted near Tokyo Islands
October 2011- 6 Western Gray whales satellite tracked
February 2011- Western gray whale makes unexpected journey