Life History and Population Dynamics of Tenualosa ilisha of Sundarban Estuary in Bay of Bengal, India for Sustainable Fishery Management

The population structure of Hilsa Shad (Tenualosa ilisha), a choicest table fish, in the estuaries of India, Bangladesh and Myanmar of Bay of Bengal has been studied by different methods and each provided complementary data on population structure. Considering the present scenario of climate change, increasing pollutant load in Indo-Bangladesh and its effect on reproduction and maturation a thorough and detailed understanding of the life cycle of Hilsa is a pre requisite criteria. However, understanding of the life history of anadromous Hilsa Shad, considering the widespread climatic changes, would be immensely important. Further, in view of increasing pollutant loads in the Indo-Bangladesh estuary region, the important area of Hilsa reproduction and maturation, a detailed work on the life history strategies of Hilsa is also need of the hour. Results of such studies would be important for sustainable management of this highly economic biological resource. The present paper deals with the aspects of life history and population dynamics of Hilsa Shad in Sundarban estuaries. The data collection was done during the period of June 2011 to March 2012 at Frasergunje Fishing Harbour and offshore, northern Bay of Bengal. The length and weight of total 617 Hilsa fish were measured under this study. Monthly variations of length and weight, length frequency distribution, monthly variation of the allometry coefficient, movement pattern, and catch per unit effort were estimated. The exploitation rate of Hilsa species was found to be 0.78 and the maximum sustainable yield was 11700.18 tonnes whereas the annual catch was 18126.00 tonnes. Highest weight of adult Hilsa was recorded during the monsoon i.e. the months of June, July and August. The result of relative yield per recruitment indicated that the mortality due to current fishing period and pressure were high. Widespread fishing of juvenile and growing Hilsa (< 500 g) declined the Hilsa population considerably losing the economic advantage. The present paper dealt with life history parameters like, growth, exploitation, mortality, stock assessment for sustainable management of Hilsa population. In our study we have observed over harvest of Hilsa fish, especially Jatka (<500 gms and <230 mm) from West Bengal coastal areas