Gray whale off coast of Namibia swam halfway around the world to get there

Gray whale
Gray whale breaching. Credit: Merrill Gosho, NOAA, Public Domain

A combined team of researchers from Durham University and Sea Search Research and Conservation NPC, has found that a gray whale spotted off the coast of Namibia traveled halfway around the globe to get there. In their paper published in the journal Biology Letters, the group describes collecting a tissue sample from the whale and comparing its DNA with other whales in other parts of the world.

Back in 2013, fishermen reported seeing a gray whale swimming around in Walvis Bay off the coast of Namibia—a very unusual sight since gray whales had not been seen in these waters before. Eventually, the reports made their way to oceanographers and zoologists and a team of researchers was formed to find out more about the whale. A was sent and the team aboard managed to obtain a small from the 40-foot whale.

Back in their lab, the researchers conducted a DNA analysis of the and then compared it with other whale samples held in biotechnology databases. They found a match—the gray whale swimming in Walvis Bay was directly related to a western population of gray that normally live in the North Pacific. Western are endangered; researchers believe that there are only 200 left in the world. Thus, sightings have been few—most have occurred off the coasts of Alaska and Russia.

Once the whale's original home had been found, the researchers began looking at different routes it might have taken to make it to a southwest part of Africa. They found it could have taken a Canadian route through the Northwest Passage. But it also could have swum down and around South America or even across the Indian Ocean. Also unclear is why the whale made such a long journey—whichever route it took would have taken it halfway across the planet, a trip that marks a record travel length for a mammal. The researchers suggest it could have been responding to warming temperatures in its natural home or it could simply have become lost.


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More information: A. Rus Hoelzel et al, Natal origin of Namibian grey whale implies new distance record for in-water migration, Biology Letters (2021). DOI: 10.1098/rsbl.2021.0136
Journal information: Biology Letters

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Citation: Gray whale off coast of Namibia swam halfway around the world to get there (2021, June 9) retrieved 20 June 2021 from https://phys.org/news/2021-06-gray-whale-coast-namibia-swam.html
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