INVESTIGATION OF THE HABITAT AND SPAWNING GROUND OF HORSESHOE CRAB BY COMBINATION OF READING OF MICRO-GEOMORPHOLOGY ON TIDAL FLAT FROM AERIAL PHOTOGRAPHS AND FIELD OBSERVATION

Abstract

An investigation method of the habitat and spawning ground of horseshoe crab Tachypleus tridentatus was developed by the combination of reading of micro-geomorphology on tidal flat from aerial photographs and Meld observations. The method was applied to the investigation at Nakatsu tidal flat in Oita Prefecture as one of the environmental assessment of the port construction. The method was compared with the ordinary observation method using line transects. Reasonable results were obtained for the investigation of the habitat of larval horseshoe crab.