About 2,500 seals were found dead on the coast of the Caspian Sea in the south Russiaofficials said on Sunday.
Regional officials initially reported on Saturday that 700 dead seals had been found on the coast, but Russia’s Ministry of Natural Resources and Environment later raised the number to about 2,500.
Authorities in the Russian province of Dagestan said it was not clear what caused the mass deaths, but they were likely to be from natural causes.
Data on the number of seals in the Caspian Sea varies greatly. The Fisheries Agency said the total number of Caspian seals is 270,000 to 300,000, while the Caspian Sea Environmental Protection Center put the number at 70,000.
Caspian seals are listed as critically endangered on the International Union for Conservation of Nature (IUCN) Red List.
Zaur Gabizov, head of the Caspian Environmental Protection Center, said in a statement that the seal most likely died two weeks ago. He added that there was no indication that they had been killed or caught in fishing nets.
Experts at the Federal Fisheries Agency and prosecutors examined the coast and collected data for laboratory research, which did not spot any contaminants immediately. Officials are now awaiting lab test results.
Many previous incidents of seal deaths have been attributed to natural causes. Kazakhstan, which has a long coastline on the Caspian Sea, has reported at least three such incidents this year.
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