Abstract
Environmental deterioration in the coastal area become serious in Japan. It is necessary to measure the environmental impact of this on the ecosystem. The biological monitoring is an effective method, but high cost, time consuming and effort are required. Snapping shrimp that makes peculiar pulse sounds are able to find along coastal area. This research examines the validity of using the pulse counts (pulse counts/minute) of snapping shrimp as a biological index. The pulse counts can be simply collected by recording snapping sounds for a few minutes using a hydrophone. The purpose of this study is to investigate the distribution of snapping shrimp along the Japan coastal area, because the inhabitation area is not clear. We observed the pulse counts from 2012 to 2016 at 66 coastal sites along the Sea of Japan. The pulse sound of snapping shrimps were observed in all regions in summer, but weren't observed in the northern end of Hokkaido in winter. The pulse counts per unit area (pulse counts/minute/100 m2) were calculated from the water acoustic receive area using GIS.
