Melting arctic sea ice linked to virus in marine mammals


Loss of ice opens pathways for disease transmission, study shows.


Melting ice is connecting marine mammals, such as these Steller sea lions, that were formerly separated, opening pathways of disease transmission.

NOAA Fisheries, Polar Ecosystems Program

Scientists have linked the decline in Arctic sea ice to the emergence of a deadly virus that could threaten marine mammals in the North Pacific.

Writing in journal Scientific Reports, researchers from the University of California, Davis, US, say phocine distemper virus (PDV), a pathogen responsible for killing thousands of European harbour seals in the North Atlantic in 2002, was identified in northern sea otters in Alaska in 2004, raising questions about when and how the virus reached them.

Their 15-year study highlights how the radical reshaping of historic sea ice may have opened pathways for contact between Arctic and sub-Arctic seals that was previously impossible.

"The loss of sea ice is leading marine wildlife to seek and forage in new habitats and removing that physical barrier, allowing for new pathways for them to move," says corresponding author Tracey Goldstein.

"As animals move and come in contact with other species, they carry opportunities to introduce and transmit new infectious disease, with potentially devastating impacts."

Between 2001 and 2016, Goldstein and colleagues tested ice-associated seals, northern fur seals, Steller sea lions and northern sea otters from Southeast Alaska to Russia along the Aleutian Islands and the Bering, Chukchi and Beaufort seas.

Satellite telemetry data helped them link animal movement and risk factor data to demonstrate that exposed animals have the potential to carry PDV long distances.

They say they identified widespread infection and exposure to the virus across the North Pacific Ocean beginning in 2003, with a second peak of exposure and infection in 2009. These peaks coincided with reductions in Arctic sea ice extent.

"As sea ice continues its melting trend, the opportunities for this virus and other pathogens to cross between North Atlantic and North Pacific marine mammals may become more common," said first author Elizabeth VanWormer.

  1. https://www.nature.com/articles/s41598-019-51699-4
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