WUHAN, May 19 (Xinhua) -- The Three Gorges reservoir in central China's Hubei Province has begun an ecological operation to stimulate fish spawning in Yangtze River.

Spawning of the four major Chinese carps, namely black carp, grass carp, silver carp and bighead carp, usually happens when two conditions are satisfied: appropriate water temperature and rising water level.

The section of the river in the province has reached 20 degrees Celsius, a suitable temperature for fish spawning.

The water storage function of the reservoir disrupted the rhythm of flooding to some extent. Thanks to a heavy rainfall forecast to hit the region in the next few days, the Yangtze River flood control and drought relief headquarters has ordered the reservoir to increase water outflow to create a flood peak that stimulates carps to spawn.

The outflow of the reservoir was 14,000 cubic meters per second on Saturday, and will be increased by 1,100 cubic meters per second every day till May 25, when the outflow will reach 20,600 cubic meters per second.

The reservoir has carried out 10 such ecological operations since 2011, and will expand the operation with other reservoirs along the river.