GAO Shilin, BAIYIN Baoligao, XU Fengran, LIU Feng, DENG Huanhuan, SHANG Xu

Abstract: The Ayu is a rare and environmentally sensitive species in the Nanxi River. Due to anthropogenic activities,the habitat of Ayu has been destroyed,resulting in a drastic reduction in the Ayu population. To restore the water eco-environment for the Ayu's habitat, the field investigation and analysis have been conducted on the water quality and benthic algae of Ayu's habitat in the Nanxi River. Results indicate:(1) the water quality in the spawning grounds during the spawning periodandin the fattening grounds during the fattening periodare relativelygood, providing favorable water quality environment forspawning and fattening the Ayu;(2) the water quality in themidstream spawning groundsand in the downstream tidal river reaches during the anadromous migration period are relatively bad, affecting the migration of Ayu from the lower river reaches to the fattening grounds;(3) abundant benthic algae (diatom as the major part) have beenfoundin the spawning and fatteninggrounds,providing favorable nutrimentenvironment forspawning and fattening the Ayu. To protect and restore the Ayu,it is suggested that thecomprehensive management of water environment should be carried out in the downstream tidal reaches of Nanxi River,with focus on the reduction of TN.

Keywords: Nanxi River; Ayu; habitat; ecological survey

(Journal of China Institute of Water Resources and Hydropower Research, Vol. 16, No. 3, 2018)