One of the world's only two populations of North Pacific right whale (Eubalaena japonica) has declined to the point where it will probably not survive.

According to new research published online June 30 in Biology Letters, a journal of the Royal Society in London, the eastern population of North Pacific right whale has shrunk to approximately 30 members, only eight of which are female, possibly making it the world's smallest whale population.

The eastern population of this whale species lives in the Bering Sea off the coast of Alaska. A genetically distinct western population in Russia's Sea of Okhotsk is believed to number as few as 300 or as many as 900 whales. The two populations are considered isolated from one another and have not been known to mingle. Neither population is well studied because the whales are so rare.

The paper calls the near-disappearance of the species a "direct consequence of uncontrolled and illegal whaling, and highlights the past failure of international management to prevent such abuses." The researchers also warn of the increased possibility of whale deaths due to ship strikes as ice over the Northwest Passage melts.

The study was led by Paul Wade of the National Oceanic and Atmospheric Administration's Alaska Fisheries Science Center, whose team conducted both aerial photographic surveys and genotyping of tissue samples from right whales in the Bering Sea. The photographic surveys revealed 31 unique whales, whereas the genotyping identified just 28.

Until 2000, scientists thought that there was just one species of right whale. Research has since shown that there are actually three species, of which the North Pacific right whale is the most endangered.

Photo: North Pacific Right Whale by John Durban, NOAA.