‍Yushu Tibetan Autonomous Prefecture in northwest China's Qinghai Province imposed a permanent ban on the release of non-indigenous fish species into the Sanjiangyuan National Nature Reserve.

The ban was implemented on Jan.1, 2019 to protect local ecology in China's largest natural reserve, the Sanjiangyuan National Nature Reserve. 

The Sanjiangyuan National Nature Reserve, or the Three Rivers Nature Reserve, covers the southern and eastern parts of Qinghai Province. It contains the headwaters of the three great rivers of Asia: the Yellow River, the Yangtze River, and the Lancang River, which is known as the Mekong River in Indo-China Peninsula. Apart from the water and wetland values, the grassland, forest and wildlife protection are also been presented as goals. 

The authorities issued the order after residents and tourists released non-indigenous fish species, such as carp into the waters as part of a Buddhist rite. Many of the fish died and rotted, creating pollution, while others invaded the habitats of different native species.

"The release of non-indigenous species can endanger the native ecology and fish. In other words, native fish are like sheep and non-indigenous fish are like tigers. If the tigers increase, they will endanger the aquatic environment," said Tsering Tashi, director of the Agriculture, Animal Husbandry, Science and Technology Bureau of Yushu Tibetan Autonomous Prefecture. 

The ruling will be enforced jointly by different departments in charge of such affairs as fishing and aquatic, and environment and market supervision. Offenders face punishment including imprisonment.