Gray whales undertake one of the longest annual migrations by mammals.To appropriately design mitigation measures across the western gray whales' geographic range, it is crucial to identify the whales' wintering areas and migration routes, and assess their spacio-temporal overlap with threat factors such as fishing gear, vessel traffic and industrial activities.
The available data do not support an unambiguous conclusion on the migratory routes and wintering grounds of the gray whales currently using Sakhalin waters as a summer feeding area. Thanks to initial satellite tagging efforts in 2010 and 2011, it is known that some of them cross the Pacific Ocean in the late fall/early winter, then migrate south along the North American coast to winter breeding lagoons before returning north and west back to Sakhalin. However, recent observations of gray whales in Japan and China (including one known individual that travelled from Sakhalin to Japan before dying in a set net) indicate that the full picture is more complicated and that some of the whales follow a different course in their annual migration.
To learn about western gray whales satellite tagging and see the maps of their dramatic migration across the Pacific Ocean, please follow the link: http://mmi.oregonstate.edu/Sakhalin2011