They would probably have been killed by a release of gas at the bottom of the Caspian Sea.
At least 2,500 seals of an endangered species have been found dead on Russian beaches, the local ecology ministry said.
The bodies of the mammals were discovered on tens of kilometers of coast in Dagestan, specified this Sunday evening the ministry of this Russian republic of the Caucasus.
Laboratory expertise is underway to determine with certainty the causes of the tragedy, added this source.
A species threatened by pollution and poaching
Interviewed on the Russian television channel Rossia 24, the head of the Russian Nature Monitoring Agency, Svetlana Radionova, indicated that it would be necessary to wait until the end of the week to have the first results of the analyzes in progress and to establish whether water pollution actually played a role in this ecological disaster.
She recalled that a similar slaughter, with nearly 2,000 seals found dead, had taken place at the end of 2020 on the beaches of Dagestan and Azerbaijan.
The Caspian seal, the only species of seal present in this sea bordering five countries (Azerbaijan, Iran, Kazakhstan, Russia, Turkmenistan), is threatened by both pollution and poaching.
At the start of the 20th century, it had more than a million seals, of which only 68,000 adult specimens remain today, i.e. less than 7%, according to the International Union for Conservation of Nature (IUCN), which considers the "endangered" species.
Intensely hunted until recently, this mammal now suffers from industrial pollution which makes it particularly sterile.
It also suffers from the drop in sea level caused by climate change.
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