抄録
Corbicula japonica is important species in the Teshio River such as fishing product. To keep clam production, it is necessary to investigate habitat condition. Therefore, we have to understand the relationship of elevation and salinity for surviving freshwater clam in the Teshio River. We observed abundance of clam, flow velocity and salinity in the Teshio River. And we conducted to measure salt water boundary using flow velocity of Acoustic Doppler Current Profiler (ADCP). Abundance survey indicates freshwater clam lives widely longitudinal, and elevation more than -1.5m. Observation result of salinity showed sea water run up completely two-layer form. Flow velocity near boundary of fresh and salt water showed a large difference. We estimate the time variation of boundary elevation using ADCP result. This estimation result suggests Corbicula japonica lives in freshwater condition, clam can hardly reproduce due to flow and salinity conditions.
