According to authorities, over 2,500 dead seals have been discovered along the southern Russian shore of the Caspian Sea.

Authorities in the Russian province of Dagestan stated that although the cause of the massive die-off was unknown, it was probably the result of natural causes.

700 dead seals were discovered on the coast on Saturday, according to initial reports from local officials. However, the Dagestan section of the Russian Ministry of Natural Resources and Environment later increased that number to roughly 2,500.

The Caspian Environmental Protection Center’s Zaur Gapizov stated in a statement that the seals most likely passed just a few weeks ago. He continued by saying there was no indication they had been killed or captured in fishing nets.

Federal Fisheries Agency experts and prosecutors examined the coastline and gathered information for laboratory analysis, which did not immediately detect any pollutants.

Numerous instances of mass seal fatalities in the past have been attributed to natural causes. At least three of these instances were reported this year in Kazakhstan, which has a lengthy Caspian coastline.

The number of seals in the Caspian varies greatly according to data. According to the fisheries department, there are between 270,000 and 300,000 Caspian seals overall, although the Caspian Environmental Protection Center estimates there are just 70,000.