Effects of water temperature on survival, development and feeding of larvae of the horsehair crab Erimacrus isenbeckii (Crustacea, Decapoda, Brachyura) reared in the laboratory

Abstract

To determine the optimal rearing temperature for the larval horsehair crab Erimacrus isenbeckii, newly hatch-ed larvae were reared in groups of 50 in 2-L beakers, the water temperature in which was regulated to 6, 9, 12, 15, 18, 21°C, respectively. Survival rates of larvae were high in the beakers at 6 to 15°C; however, mass mortality occurred in the beakers at 21°C from the third to fourth zoeal stage and at 18°C from the fifth zoeal stage through megalopa to first crab stage. The number of days required to reach each larval stage decreased with increasing temperature to 15°C. The coefficient of variation of the number of days required to reach the first crab stage was high in the beakers at ≥15°C. Carapace length tended to increase with decreasing temperature. The numbers of prey eaten by larvae were high at 9 to 15°C. We concluded that the optimal rearing temperature range for larvae of the horsehair crab was from 9 to 12°C.