Melting Arctic Ice Is Creating Greater Viral Threats to Seals

An adult male ribbon seal lays on the ice. (Photo courtesy of NOAA)

(CN) – As viruses travel through melting Arctic ice due to climate change, sea mammals like harbor seals will be more susceptible to certain pathogens that could kill them as they travel between the North Atlantic and the North Pacific oceans, according to a new study published on Thursday.

New water routes will allow for contact between populations that were previously isolated from each other and that could mean the shifts in sea ice will be accompanied by widespread exposure.

Researcher Tracey Goldstein with the University of California Davis and her colleagues analyzed the timeline of the phocine distemper virus (PDV) that killed large amounts of harbor seals between 1988 and 2002. The virus was also found in the North Pacific in 2004, according to the study published in the journal Scientific Reports.

Arctic sea ice is melting faster than it can re-freeze in the winter and this trend has ramped up the last few decades.

According to the National Snow & Ice Data Center, Arctic sea ice cover averaged 2.19 million square miles this past October, which is the lowest in the 41-year continuous satellite record.

Researchers found that when PDV was introduced into the North Pacific, it infected ice seals, steller sea lions, northern fur seal and sea otters. The team studied the exposure, risk factors and patterns of transmission collected over a 15-year period.

Infection with PDV in the North Pacific in 2003 and 2004 was widespread, with over 30% of animals testing positive for the virus. The infection rate ebbed and flowed through 2009, but the chances of infection were 9.2 times higher in animals sampled in 2004 and 2009, relative to other years, according to the study.

This coincided with open water routes in 2002, 2005 and 2008, which were detected using satellite photos.

Study results show exposure and infection extensive in the North Pacific after 2002. Study authors say open waters could mean more routes for sea mammals, but also increases the risk of pathogens to cross between oceans as Arctic sea ice continues to melt.

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