Abstract

• A study on the characterization of the ovarian development in the freshwater prawn Macrobrchium johnsoni was conducted. The specimens were from Ayeyarwady segment of Myinmu Township. A total of 1621 specimens (550 ovigerous females and 1071 non-ovigerous females) of M. johnsoni were collected. A total of 20 female prawns were randomly chosen to study the reproductive biology. Four stages of ovarian development were recorded; Stage I ovary (Predeveloping), Stage II ovary (Developing), Stage III ovary (Maturing) and Stage IV ovary (Ripening) according to both morphological and histological observations. The results indicated that freshwater prawn M. johnsoni can spawn the whole year round according to the record of occurrence of ovigerous females, the fluctuation of GSI values and occurrence of oogonia and maturing oocytes throughout the study period. It was assumed that the reproduction of the study species may be continuous type. The present study provides important information on the reproductive biology of crustaceans in general and also can serve as a significant foundation for aquaculture of a freshwater prawn species.