The Bering Sea and Gulf of Alaska once teemed with tens of thousands of North Pacific right whales but hunting in the 19th century wiped out most of them, with up to 30,000 slaughtered in the 1840s alone. Poaching by the Soviet Union during the 1960s claimed several hundred more, making the North Pacific right whale probably the most endangered species of whale on Earth. Numbering well under 50, these whales which can reach up to 18 metres in length fall below the IUCN's threshold of likely viability as a species and the the small number of females is especially worrisome. A genetically distinct population of right whales in the western Northern Pacific is in slightly better shape with several hundred individuals, but is nonetheless listed as "critically endangered" on the IUCN's Red List, the most scientifically respected index of threat level.

To carry out the census, researchers used two standard method for measuring whale populations, one was based on photos taken during visual sightings, from airplanes during the period 1998 to 2001 and again in 2008, and from ships in 2005 and 2007. The other involved collecting biopsy tissue samples to gather genetic material, with a total of 43 taken over a 10-year period. The two independent methods yielded nearly identical results - 31 individuals through photography, 28 through genotyping and therefore lending more weight to the grim results.

image (c) NOAA