Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the

Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the middle

reaches of the Changjiang River

LI Mingzheng;DUAN Zhonghua;GAO Xin;CAO Wenxuan;LIU Huanzhang

【期刊名称】《中国海洋湖沼学报（英文版）》 【年(卷),期】2016(034)005

【摘要】Silver carp (Hypophthalmichthys molitrix),bighead carp (Aristichthys nobilis),grass carp (Ctenopharyngodon idella),and black carp (Mylopharyngodon piceus) are the four major Chinese carps and are commercially important aquaculture species in China.Reproduction of these carp has declined since the construction of the Three Gorges Dam (TGD) due to an altered water flow and thermal regime in the Changjiang (Yangtze) River.However,details of the changes in reproduction of the four species are not well understood.To assess the impact of the TGD on reproduction of the four carp,we investigated their eggs and larvae at Yidu City,which is 80 km below the TGD,during 2005-2012.We examined differences in larval abundance of the four species in the Jianli section (350 km downstream of the TGD) before (1997-2002)and after (2003-2012) construction of the TGD.Based on these observations,the first spawning date of the four species was delayed a mean of about 25 days after the dam was constructed.Mean egg abundance in the Yidu section of the river was 249 million and