Gray whale travels more than 22,000 kilometres, smashes world record

Thursday, April 16, 2015, 11:11 AM -

The round-trip trek of one gray whale has set a new record for the longest mammal migration, covering a distance of more than 22,000 kilometres across the Pacific Ocean.

While this number has astonished researchers, it also raises new questions about the threatened status and behaviour of the species.

The western North Pacific gray whale is listed as critically endangered, but the latest findings indicate that population numbers could be higher than originally thought.

The record-setting whale, known as Varvara ('Barbara' in Russian) swam the great distance over a nearly 6-month period between 2011 and 2012.

She is one of three western grays tracked by a team of scientists from Russia and the United States using satellite-monitored tags.

Unlike other western gray whales, who tend to migrate along the eastern coast of Asia, Varvara took a more transoceanic route. She made her way from the whales' primary feeding grounds off Russia's Sakhalin Island all the way across the Pacific Ocean to Baja, Mexico and back again.

Her journey included visits to the breeding grounds of eastern gray whales, a similar species found off the coast of North America, and one that is not endangered. 

While the eastern and western gray whales have long been thought of as two distinct species, Varvara's trip points to the fact that the two may not be so different after all.

Both the western and eastern gray whales are known to interact in the wild, and share common threats to their existence. Whaling and commercial fishing have decimated the numbers of both species over the years. The eastern population rebounded with the help of conservation efforts, and have a current estimated population of more than 18,000.

Western gray whales were thought to be totally extinct at one point, until a small group was discovered in the waters off Sakhalin Island in the 1970s. Scientists estimate that there are about 150 western grey whales currently living there.

The fact that whales like Varvara are capable of travelling across the ocean's open waters mean that population numbers could be skewed. Western grays may have been misidentified as eastern and vice versa.

Experts say that more studies will be required to determine if this is true ,and if the western gray is actually endangered.

Until then, Varvara maintains an impressive record and well-travelled whale status.

Source: Oregon State University

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