Duration of development in the larval and early juvenile stages H. coarctatus was studied in relation to temperature, and compared at extreme (18 and 6 °C) than at intermediate (9 to 15 °C) temperatures. The results were used to estimate the duration of development from hatching to the third crab stage in the field. Settling and metamorphosis was predicted to occur mainly during June. Biomass increased exponentially during larval development. Juvenile growth was also exponential and was maximum at 9 degree C, and minimum at 18 and 6 °C.