The native fish Ayu in Xindian Creek is inhabited in clean and pellucid streams of cold water. However, due to destroyed Ayu’s rehabilitation and plentiful upstream water reservoirs, the indigenous catadromous species Ayu has already gone extinct.

Rebuilding of Xiadian Creek Bitan Weir incorporating the water environment improving project to overcome the existing large-scale weir setbacks, The NTHU professor Dr. Tzeng C. S. optimize fish pass as compensatory habitats and migration corridors for Ayu.