The death of thousands of sea urchins and starfish in a bay near Petropavlovsk-Kamchatsky last month was most likely caused by a powerful storm, prosecutors said Friday.
Water and marine life samples from Avachinskaya Bay did not show any sign of chemical, radioactive or bacteriological contamination, the inter-regional environmental prosecutor's office said.
The authorities did not find any evidence that illegal activity caused the mass deaths, Interfax reported.
In October, vast amounts of dead sea urchins and starfish washed up on the shore near Petropavlovsk-Kamchatsky, the capital of Russia's far eastern Kamchatka region.
Sixty-five dead sea urchins and 12 dead starfish per square meter were found along a 250-meter long stretch of coastline.
At the time, scientists believed that the bay could have been contaminated as a result of industrial waste discharges.