Spawning Migration of the Horseshoe Crab, Tachypleus gigas (Millier), in Relation to Lunar Cycle

Abstract

Effects of lunar phases and tidal height on the spawning migration of the horseshoe crab, Tachypleus gigas (Moller), along the northeastern coast of India were studied. Mature pairs of crabs migrate towards the shore and build their nests in sandy beaches for spawning throughout the year with maximum activity during April-October at highest high tides of the full moon and November-February during new moon phases. The tidal height showed a significant correlation with the number of crabs migrating towards the beach for spawning.