Abstract：Riverbed substrate is important to many riverine organisms, however, it is normally difficult to study the substrate intensively especially in large and fast flowing rivers. The Chinese sturgeon Acipenser sinensis is a critically endangered fish species, it spawns on a specific riverbed substrate. In this paper, the hydroacoustic and underwater optical video technologies were integrated to study the riverbed substrate at the only remaining spawning area of the fish. Sixteen samples were firstly studied to verify the relationship between acoustic backscattering characteristics (hardness and roughness) and video observed characteristics (embeddedness and medium diameter of the grain). Then eight vertical mobile hydroacoustic surveys were conducted to acoustically map the 16 km spawning reach. The results revealed that the heterogeneous mix of boulder/cobble and sand was the dominant substrate at the spawning reach. However, the embeddedness and medium diameter of the grain varied within the area which tend to affect the spawning site selection of the fish. This study indicated that the combination of hydroacoustic and optical video technologies could be very useful to study the riverbed substrate in river ecological issues.

Hui Zhang , Chengyou Wang , Hao Du, Jinming Wu, Li Shen, Qiwei Wei. Integrating hydroacoustic and optical video technologies to identify the riverbed substrate at the spawning reach of Chinese sturgeon. Advanced Materials Research, 2014, 955-959: 1235-1240.