Around 2,500 seals have been found dead along the shores of the Caspian Sea in Dagestan, South of Russia.
Local authorities are puzzled by the discovery and how the Caspian seals died, but believe it was likely to be due to natural causes.
The number is expected to grow according to the Ministry of Natural Resources of Dagestan, who have ruled out any form of hunting causing the deaths.
They said that from judging their appearance, the seals died about two weeks ago and there were “no signs of violent death, no remains of fishing nets.”
Caspian seals have been classified as endangered and have been on the red list of the International Union for Conservation of Nature since 2008.
The bodies were found at different locations and they announced in their telegram that: “Large numbers are in the Yuzbash area, as well as between the mouths of the Sulak and Shurinka rivers.”
Earlier this year a similar incident occurred where 140 Caspian seals were found dead on the Kazakh beaches of the Caspian Sea.
Caspian seals are the only mammals found in the Caspian Sea and the data available on the number of them vary widely.
The fisheries agency has said the overall number of Caspian seals is 270,000-300,000, while the Caspian Environmental Protection Center put the number at 70,000.
The Caspian Sea, the largest landlocked body of water in the world, is bordered by five countries: Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan.
Earlier in October, hundreds of pilot whales were found dead at the Chatham Islands in New Zealand.
They were stranded near the shark-infested waters of the remote island chain in the South Pacific and nearly 500 whales were washed up in the waters.
The bodies piled up in two separate mass-stranding events reported by residents throughout the weekend.