Peninsula Valdés, in the Argentine province of Chubut, is home to the largest continental colony of elephant seals in the world .
By the end of 2023, it was approaching 60,000 individuals, when an outbreak of avian influenza killed nearly all the pups born that year and up to 60% of the breeding females in the highest density areas.
A year and a half later, Argentine scientists warn in an article published in the journal Marine Mammal Science that the community has gone from being out of danger to being considered vulnerable and estimate that it will take decades to reverse the effects of the disease. According to a census, of the approximately 18,000 elephant seal pups born in 2023 on the peninsula, 97% have died .
Many newborns of this species do not survive their first year of life, hunted by sharks, sea lions and killer whales, among other predators.
If the virus had stopped there, researchers predicted it would take the colony about a decade to recover. But the census conducted at the end of 2024 — pending the inclusion of the results of the aerial images — shows that it has also decimated the females of reproductive age: in the areas of highest density, up to 60% fewer were counted than in previous years, and in the others, the decline was about 30%.
The death of thousands of specimens of this popular mammal has concerned the authorities of Chubut and the local legislature has approved a law declaring the protection of the species Mirounga leonina throughout the province, including colonies formed outside the boundaries of the protected natural area of the Valdés Peninsula.
(Online Union)