Reproductive Cycle of the Mud Eel, Monopterus Cuchia (Hamilton-Buchanan, 1822) in Bangladesh

Developmental stages of both male and female gonad and estimation of gonadosomatic index (GSI) of Monopterus cuchia investigated over a period of two years. Four developmental stages such as, spermatogonia, spermatocytes, spermatids and spermatozoa were identified in testis. Three developmental stages of oocytes such as, ogenesis (oogonia, early perinucleolus stage and late early perinucleolus stage), vitellogenesis (early vitellogenic oocytes, advanced vitellogenic oocytes and maturation stage) and atretic stage were differentiated in ovary. Maximum mean gonad weight recorded in May for both female (62.82±3.02 g), and male (8.20±0.48 g). The testis at early development stages between October and March contained mostly spermatogonia, spermatocytes and spermatids, although a small amount of spermatozoa was also found in March. The mature testis began to develop in the early April and was prominent from May to July. Highest percentage of oogonia in the ovary recorded in the month of November and highest percentage of early and late perinucleolus stage was recorded in the month of January. Matured oocytes occupied the most areas of the ovary which were observed from March to November but it was prominent in May. Oocytes were ovulated in the spawning period and began to absorb from late July.