Reproductive Cycle of the Endangered Sarpunti, Puntius sarana (Hamilton, 1822) in Bangladesh

Abstract

Successive developmental stages of both male and female gonads and estimation of gonado-somatic index (GSI) of Puntius sarana (Hamilton 1822) were investigated over a two year period (October 2002 to September 2004). From the histological analysis, four developmental stages such as spermatogonia, spermatocytes, spermatids and spermatozoa were identified in testes. 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 distinguished in ovaries. Maximum mean gonad weight was recorded in June for both females (8.92±0.01 g) and males (4.48±0.21 g). The testes at early development stages between October and March contained mostly spermatogonia, spermatocytes and spermatids, although a small amount of spermatozoa was also found in late March. The mature testes began to develop in early April and were prominent from May to September. Highest percentage of oogonia in the ovary was recorded in the month of November; while the highest percentages of early perinucleolus stage and late perinucleolus stage were recorded in the month of January. Vitellogenesis (matured oocytes) occupied the most areas of the ovaries which were observed from May to mid September but was prominent in June. All oocytes did not mature at the same time. Only the matured oocytes ovulated in the spawning period while immature oocytes gained maturation under way of vitellogenesis and released at the second spawning time in the months of August and September.