Russian authorities said they are investigating the death of nearly 300 endangered seals, including pregnant females, that have been found washed up on the shores of the Caspian Sea since December 6.
On Monday, the state fisheries agency in Dagestan, told Russian state media that 23 more seals had been discovered at the mouth of the Sulak River north of Makhachkala, the capital of Dagestan.
The dead seals washed up at various places in the southern region of Dagestan, on the edge of Russia that stretches from the Caspian Sea into the Northern Caucasus, including its regional capital Makhachkala, the state fisheries agency told Russian media.
The cause of the deaths is unclear. A team from the Russian Academy of Sciences has arrived from Moscow to investigate.
The Caspian seal is the only mammal living in the Caspian Sea, the world’s largest inland body of water. The seals have been endangered for years due to over-hunting in the sea, which is shared by Russia, Kazakhstan, Azerbaijan, Iran and Turkmenistan.
The states have extensive oil and gas reserves that affect the sea. Pollution and climate change have added to declining water levels, threatening many species in the area.
Since 2008, Caspian seals have been listed as endangered by the International Union for Conservation of Nature (IUCN). Experts say there are now about 70,000, down from more than one million in the early 20th century.
The Caspian seal was included in Russia’s Red Data Book of rare and endangered species this year.
The latest mass seal death is part of a recent string of ecological disasters causing marine wildlife deaths that have sparked environmental fears.
Two months ago, the sea surrounding the Kamchatka peninsula in Russia’s far east was coated in a yellowish foam and beaches littered with dead animals.