Natural spawning of Chinese sturgeon during the 175 m tentative impoundment of Three Gorges Dam

The impoundment of the Three Gorges Project (TGP) may influence the natural reproduction of the Chinese sturgeon. From 2009 to 2011, a five-method investigation was conducted to analyse this influence. The Chinese sturgeon reproduced in late November 2009 to 2011, which was about two weeks later than in 2003 to 2006. The water discharge and water temperature did not exhibit any evident difference from 2003 to 2011. The investigation showed that the spawning sites transferred near the Gezhouba dam in 2010 and 2011. The estimated parent Chinese sturgeon greatly increased in 2011, which suggested that stopping the catching of parent fish increased the natural spawning number. The integral survival rate before the fish enters into the sea should be assessed, however. All the monitoring dates from 1997 to 2011 showed that the Chinese sturgeon could finish natural reproduction, while the Three Gorges Dam operated during the 175 m trial impoundment. Yet, spawning time was delayed and water temperature during spa...