Gametogenic cycle with seasonal variation of Perna viridis in Moheskhali Channel, Bangladesh

Abstract

Green mussel (Perna viridis) is one of the most potential mariculture shellfish species not only in context of Bangladesh but also for the world. A thorough study on the reproductive biology of P. viridis and determination of the accurate spat collection time is essential to develop the green mussel culture technology. Therefore, the main purposes of this study was to determine dynamics of the gonadal development accurately through histology, and to find how condition index (CI) is linked with the spawning of the green mussel. Twenty green mussel were collected each month from November 2017 to October 2018 from Moheskhali Channel, Chawfaldandi, Cox’s Bazar. Collected samples were brought to the laboratory to measure body length, body weight, muscle weight, and dry weight. The general reproductive condition of the population were assessed by calculating mean gonadal index (GI). From the histological analysis, the sex ratio of male and female was found tas 1:0.93 and no evidence of hermaphroditism in P. viridis were documented. There was a significant relationship between length and weight where R² value was found to be 0.92, indicating a positive correlation between this parameters. The male CI value was relatively higher than female. The highest value of female and male GI were observed to be 2.1 and 2.4 in the month of January and February, respectively, and a minor increase was observed in the month of June. GSI (gonadosomatic index) value was found to be generally higher in male than female. The study confirmed that the spawning of green mussel occurred twice in a year with major spawning season from November to March and a very minor spawning during the month of June to July. However the study will be helpful for naturally occurring green mussel stock management and to develop future aquaculture aspect in Moheskhali Channel.