STUDY ON FEEDING BIOLOGY OF HILSHA (TENUALOSA ILISHA) IN THE COASTAL WATERS OF CHATTOGRAM

Abstract

Hilsha (Tenualosa ilisha) is the national fish, engages the most important open water single species fishery in Bangladesh. This study was designed to describe about the feeding biology of Hilsha (T. ilisha) in coastal waters of Chattogram. For this research work, fishes were sampled from February, 2019 to January, 2020 and collected from 3 stations in coastal waters of Chattogram, Bangladesh and laboratory analysis conducted from Marine Bioresource Science Lab, Chattogram Veterinary and Animal Sciences University, Chattogram. To analyze gut content, seasonal variation of food and feeding habits and length and weight relationship with their food and feeding habits were analyzed in the study. To determine the whole condition, various methods such as numerical method, frequency of occurrence method, index of fullness method, point’s method and statistical analysis (Correlation and Regression Analysis) were performed to complete the study. According to point’s method, higher amount of plankton found in stomach content in winter than other season of the year. By correlation and regression analysis, (401-500) g and (301-400) g had consumed highest amount of plankton. In index of stomach fullness method, 3/4 full found in 3 different sizes (21-30cm, 31-40cm, 41-50cm) of Hilsha (T. ilisha) fed phytoplankton much more than zooplankton. There was no empty stomach found throughout the study. 93% phytoplankton and 7% zooplankton were found in gut analysis where Bacillariophyceae (57%), Chlorophyceae (29%), Dinophyceae (4%), Cyanophyceae (2%), Pyrrophyceae (2%) and Copepoda (2%), Cladocera (1%), and Rotifera (4%) were found in the gut. From the analysis, it was found that T. ilisha was preferred phytoplankton to zooplankton. It also was observed that, Bacillariophyceae and Chlorophyceae was the most preferable food item to Hilsha shad (T. ilisha). This study describes biology of Hilsha, existing Hilsha conversation and management strategy and its influence on Hilsha.