June 30, 2010

North Pacific Right Whales Face Extinction

According to a study released on Tuesday, the world's smallest known whale population has dwindled to about 30 individuals, only eight of them females.

The Bering Sea and Gulf of Alaska once swarmed with tens of thousands of North Pacific right whales.

However, according to the International Union for the Conservation of Nature (IUCN), hunting in the 19th century wiped out most of them, with up to 30,000 slaughtered in the 1840s alone.

The Soviet Union's poaching during the 1960s claimed several hundred more, making Eubalaena japonica the most endangered species of whale on Earth.

"Its precarious status today ... is a direct consequence of uncontrolled and illegal whaling, and highlights the past failure of international management to prevent such abuse," said the study, published in the British Royal Society's Biology Letters.

The eastern North Pacific right whale falls below the IUCN's threshold of likely viability as a species.

The study, which was led by Paul Wade of the Alaska Fisheries Science Center, said that the limited number of females is a big threat.

A genetically distinct population of right whales in the western Northern Pacific is in slightly better shape with several hundred individuals.  However, it is also listed as "critically endangered" on the IUCN's Red List, which is the most scientifically respected index of threat level.

"The probability of ship-strike mortalities may increase with the likely future opening of an ice-free Northwest Passage," the researchers note.

Wade and colleagues used two standard methods for measuring whale populations in order to carry out their census.

One was based on photos taken during visual sightings from airplanes between the years 1998 and 2001 and again in 2008.  Photos were taken from ships during sightings between the years 2005 and 2007.

The other involved collecting biopsy tissue samples to gather genetic material, with a total of 43 taken over 10 years.

The two independent methods provided nearly the same results, with 31 individuals seen through photography and 28 through genotyping.


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