Bird flu has wiped out half of the breeding elephant seals in South Georgia, according to a study that warns of “serious consequences” for the future of the species.
The remote island in the South Atlantic Ocean is home to the world's largest population of southern elephant seals. Researchers estimate that 53,000 women died from bird flu in 2023.
According to researchers, the population has now fallen by 47%. “It was a pretty significant number,” said lead author Connor Bamford of the British Antarctic Survey in Cambridge. “I didn’t expect it to be so tall.”
In 2024, tourists on cruise ships told researcher Ernest Shackleton's grave has become inaccessible visitors due to “dead seals blocking the way.” But Bamford said it was likely many of the dead animals were never seen because they returned to the sea when they were sick to cool off.
It is possible that direct losses from avian influenza are exacerbated by females becoming physically stressed and abandoning their young.
“We knew there was a high mortality rate – well above normal levels – but it wasn't until we did the before-and-after comparison that we were able to see how high it was,” Bamford said. In the long term, he said, it would have a “dramatic impact on the population.”
The island in the South Atlantic is home to 54% of the world's breeding population elephant seals. The team used aerial photographs of three beaches to compare the 2022 breeding population to 2024. according to the newspaperpublished in the journal Communications Biology.
Mortality rates are particularly high among cubs, and females take three to eight years to begin reproducing.
“One of my colleagues is currently on a ship there and the number of cases this year is lower than last year. This suggests that the virus is circulating in the population,” Bamford said. “I wouldn’t say it’s all over.”
Research shows that avian influenza continuing to spread among bird and mammal species in Antarctica.
“The apparent loss of nearly half of the breeding female population has serious implications for… future population stability,” the researchers said in the paper. “These results highlight the urgent need for ongoing and intensive monitoring.”
The current highly pathogenic strain of avian influenza, H5N1, was originally discovered in Europe and then spread to America. It reached South Georgia in 2023.but it took time to calculate its impact because the islands are so remote.
“The results of this study are heartbreaking,” said Professor Ed Hutchinson, a virologist at the University of Glasgow who was not involved in the study.
“It is unclear how severe the impact of this virus will be on other mammal and bird species in Antarctica and the sub-Antarctic,” he said. “All we can do is wait and watch.
“H5N1 has already had a devastating impact on ecosystems around the world, from seabird colonies in the UK to sea lions in South America. We'll soon know what this will mean for Antarctica.”
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