A study on hydrological and hydraulic features of trachidermus fasciatus migration

Abstract

Trachidermus fasciatus is a Catadromous species. The downstream of Aihe River is a natural habitat of Trachidermus fasciatus along the Yalu River. Generally, the pattern of hydrology and hydraulic has important impact on the life cycle ofdiadromous species, eg, spawning, overwinter, and feeding. The paper analyzes the hydrological and hydraulic features during the period which the young fish migrate upstream for feeding and adult fish migrate into sea for reproduction. According to the research, there is a regular process of discharge swelling and falling, which lasts for a relatively long period of time under both annual and inter-annual hydrologic condition. During swelling period, the daily average discharge varies frequently while being generally stable and lasts for more than 40 days and the average flow velocity is 0.4-0.6m/s; during falling period, the change of daily average discharge is smaller and the period with relatively stable water flow lasts about 30 days, the average flow velocity is about 0.4m/s.