Russia's minister of natural resources says the mass death of marine life off the coast of the Kamchatka region in the Far East is due to "natural causes" and excluded any manmade causes.
Dmitry Kobylkin said in a televised interview on October 23 that the mass death was caused by "toxic algae."
"We have not found any leaks of oil products or any other types of extreme excesses that could lead to the death of aquatic organisms," Kobylkin said.
According to Kobylkin, a special scientific expedition next year will work on finding causes of what might have caused the outflux of toxins from the algae.
In late September, residents of local settlements and surfers complained that the waters near the Kamchatka Peninsula had changed color and a large number of marine animals, such as octopuses, sea urchins, starfish, and others, started dying en mass.
The residents also complained that they experienced sore throats and eyes inflammations after swimming in the area.
Meanwhile, environmental group Greenpeace warned of an ecological disaster in the area.
Greenpeace activists who travelled to the site said they had found yellowish foam on the ocean's surface in several places. The World Wide Fund for Nature (WWF) conservation group said the pollution appeared to be caused by a highly soluble substance.
Russia's Investigative Committee opened a criminal case over the pollution, saying in a statement that they were treating a bloom of naturally occurring algae as the most likely cause.
It said in a statement that elevated levels of phenols -- an oil product -- in water were not critical and had been found in the Avacha Bay on Kamchatka's southern coast since 1970.