The Songjiang District Water Authority has retrieved about 250 kilograms of dead fish from a river in Songjiang district in Shanghai since Wednesday, the Oriental Morning Post reported Sunday.
The cause of death of the fish is so far unknown. Samples have been sent to the Shanghai Municipal Agricultural Commission for further study, according to the report.
Residents who walked past the Sijingtang River on March 29 found the putrid, dead fish and reported the case to the Songjiang District Water Authority, the report said.
The district water authority first retrieved about 150 kilograms of dead fish on Wednesday, and 100 kilograms two days later, Gao Yunchu, director of the Songjiang District Water Authority, told the Oriental Morning Post.
Investigations of nearby factories showed that they did not discharge poison pollutants into the river and have nothing to do with the incident, said Cao Haiyun, an official for the Songjiang Environmental Protection Bureau.
Investigations also showed that dead fish did not affect the water quality, Cao added.
The fish may have been killed by people who wanted to catch them, Gao told the Oriental Morning Post.
The fish may have been shocked to death with electricity, because residents saw people trying to catch fish with electricity in the evening, another official surnamed Xu from the Songjiang Environmental Protection Bureau told the Shanghai Evening Post.