Hilsha shad (Tenualosa ilisha, Hamilton 1822) is the most commercially important and national fish of Bangladesh, belongs to the family of Clupeidae of the Clupeiformes. The study was conducted to identify the seasonal gonadal cycles through histological study and the peak breeding season combining histological and Gonado Somatic Index (GSI). One hundred and twenty fish samples with an average weight of 756.75±6.25 g was collected from the Tentulia river for the study throughout the year. Monthly mean GSI values of females ranged from 6.36±0.69 to 15.02±1.33. The lowest mean GSI value was found in December and the highest GSI value was in October. From the histological observation of the ovary, early perinucleolar stage, late perinucleolar stage, yolk vesicle stage, yolk granule stage, pre-mature and mature stages were identified. The highest percentage (75%) of mature oocytes and peak breeding season were observed in October and the breeding season continues from October to November. These results will be helpful for fishery managers to impose adequate regulations for sustainable fishery management in Bangladesh.

Oyster and mussel farming along the coasts and the desire to increase fishing revenue have created a boom in these types of farms. An experiment on culture of edible oyster (Saccostrea cucullata) and green mussel (Perna viridis) was performed at Gangamoti estuary in Kuakata, Bay of Bengal coast of Bangladesh from December 2021 to March 2022 to find out the appropriate culture method of the oyster, S. cucullata and green mussel, P. viridis. Initially, the average shell heights of S. cucullata and P. viridis were 8.8±1.62 and 6.9±1.89 cm, respectively; where average weights were153.4±13.23 and 84.78±11.78 g, respectively. After the culture period, oysters shell height and weight grew up to 9.1±1.98 cm and 163.2±12.54 g, respectively in rectangular basket and 8.9±1.45 cm and 157.2±11.31 g, respectively in velon screen bag. In case of oysters, the rectangular basket and velon screen bag displayed the minor progress in specific growth rate, 0.09±0.01 and 0.07±0.03, respectively. But green mussels did not show any growth rate. Oysters cultured in rectangular basket showed total mortality at day-90 and velon screen bag at day-75. Green mussels showed 100% mortality within 21 days of culture. Our experiment was the first attempt to culture these two mollusks in the Kuakata coast of Bangladesh. However, further intensive researches would be required to evaluate the culture feasibility of these two mollusks’ species in the Kuakata coast of Bangladesh.

Clarias batrachus (Linnaeus, 1758) is a popular food fish of Indian sub-continent due to its high nutritional value. Earlier many workers have carried out studies on feeding and breeding biology of this fish species but convulsive information on the same is not available. So, a survey of published literatures on the induced breeding of C. batrachus has been carried out to consolidate the available information. Environmental factors play an important role in regulating reproduction in fishes. Pituitary gland extract, HCG and synthetic hormones viz., ovaprim and ova tide are successfully being tested for the induced breeding of fishes by various researchers under different climatic conditions, with varying degree of success. Chasm of information has been pointed out for further study mainly on age group wise variation in food preference and correlation of breeding periodicity with hydrological parameters and photoperiod.