SYNCHRONISATION OF MOLTING AND OOGENIC CYCLES IN A CONTINUOUSLY BREEDING POPULATION OF THE SAND CRAB EMERITA ASIATICA ON THE MADRAS COAST, SOUTH INDIA

Abstract

Abstract In the mole crab Emerita asiatica, the female reproductive cycle is repetitive; when the pleopodal embryos undergo development, there is a concurrent maturation of oocytes within the ovary making it ready for the next spawning. However, molting occurs after hatching of the larvae from the pleopods and before spawning. In E. asiatica, the developmental changes of setae on the pleopods and the extent of epidermal retraction were used to define the molt cycle stages. Contrary to earlier reports on embryo-carrying decapods, in E. asiatica the first sign of molting, viz., the retraction of epidermis, is evident even before the hatching of the embryos. The premolt stages advance further up to D1, at a time when the pleopodal embryos hatch. No female at the time of embryo hatching is in the intermolt. Both ovarian index and total ovarian proteins gradually increase from the intermolt stage C1 to C3, thereupon maintaining the same level up to spawning. In continuously reproducing females (size class 23–3...