Effects of Temperature and Diurnal Cycle in the Molting Schedule of Mangrove Crab, Scylla serrata (Forskål, 1775)

Abstract

Soft-shell crab farming is gaining popularity since all crab parts can be eaten with almost no discards. However, its biggest challenge is the tedious monitoring every 4-hour interval to check for molting. A total of 90 mangrove crabs weighing 80-100 g were stocked in individual crab trays, recording 24-hour water temperature and incidence of hourly molting for 57 days to provide another basis for monitoring and cues in the molting schedule. Results showed that molting (82.24 %) happens at optimum temperature (Topt) levels, between 27–31°C, with a high incidence of molting (85.29 %) at nighttime when the water temperature is lower and within the Topt. Findings suggested that aside from 4-hour intervals, monitoring of molting for soft-shell crab farming is recommended at nighttime and early morning.