Approximately 10,000 tons of farmed fish, mainly sturgeon, escaped downstream into the middle and lower reaches of the Yangtze River via a discharge of water from a dam, an event experts believe could spell disaster for the endangered Chinese sturgeon in the wild.
An official with the Ministry of Agriculture's office supervising the fishery of the Yangtze River Basin told the Global Times on Wednesday that authorities are trying to catch the fish to control the damage. Meanwhile, they are also monitoring the ecological environment in the river's middle and lower reaches.
Authorities have said flooding was the fundamental cause of the ecological disaster.
Due to heavy rain this summer, water was discharged from the dam at Geheyan hydropower station on the Qingjiang River - a tributary of the Yangtze River in Hubei Province - on July 19, the first flood discharge from the dam in 18 years, news site thepaper.cn reported.
Some of the fish were killed, but many escaped to other areas of the Yangtze River, such as Dongting Lake in Hunan Province and Poyang Lake in Jiangxi Province, an anonymous official told thepaper.cn. "They are everywhere!" he said.
The release of the farmed fish will be a huge disaster for the Yangtze River's ecological environment and its aquatic wildlife, Wei Qiwei, a researcher at the Yangtze River Fisheries Research Institute, told thepaper.cn.
"Those fish, including … Siberian sturgeon and kaluga sturgeon, normally will not come to the Yangtze River … If they escape from the fish farms, they will go compete with local animals for food and territory."
Wei said the Kaluga sturgeon was originally native to Northeast China's Heilongjiang Province and is bigger and more ferocious than most fish in the Yangtze's freshwater environment, so it can hunt and eat other aquatic animals in the Yangtze River easily.
"The genetic pollution is even more dangerous," Wei explained. The non-native sturgeon will mate with Chinese sturgeon in the Yangtze, mixing the genes of the two species and eventually ensuring an end to purebred Chinese sturgeon.
The Chinese sturgeon (Acipenser sinensis) is an endangered species designated for "first level" protection on China's national list of protected wild animals.
