The Russian Federal Agency for Fishery's regional branch said on Saturday that about 700 dead seals were found near an oil depot in Makhachkala's Kirovskiy district. Caspian seals die in bunches and are found on Dagestani shores every few years, with the latest episodes recorded in 2016 and 2020.
"As a result of autopsies, a large volume of samples was collected to conduct a detailed bacterial analysis, virological studies, including the study of tissues for the COVID-19 virus. The materials were sent to laboratories in Moscow and Astrakhan for research. Natural factors were recognized as the main version of the death of the Caspian seal," the ministry said in a statement.
The study of internal organs' condition did not confirm the hypothesis of their intoxication with heavy metals or pesticides, according to the ministry.
The ministry specified that the new episode of seal death would not critically affect their population, since it is stable and ranges from 270,000-300,000 animals.
Meanwhile, Caspian Nature Conservation Center head Zaur Gapizov told Sputnik on Sunday that the number of seals found dead in the area in the past few days has increased to 1,700 and their condition suggests they died about two weeks ago.
"We did not find any signs of violent death or remains of fishing nets. The actual number of dead seals is likely much higher," Gapizov said, adding that the center's shore patrol, along with inspectors from the Federal Agency for Fishery and employees of other environmental agencies, continue to explore the coast.
The Caspian seal is an endemic and the only marine mammal species found in the Caspian Sea that plays a unique role in the marine ecosystem. Cases of detection of dead seals off the Caspian coast in Dagestan have increased in recent years. The Federal Agency for Fishery believes the most likely cause of the seals’ death is the release of natural gas abundant in the Caspian Sea.