1Minamiizu Station, National Center for Stock Enhancement, Fisheries Research Agency, Minamiizu, Shizuoka 415-0156, 2Department of Marine Biosciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, 3Tamano Station, National Center for Stock Enhancement, Fisheries Research Agency, Tamano, Okayama 706-0002, Japan
To determine the optimal rearing temperature for the larval horsehair crab Erimacrus isenbeckii, newly hatched 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.