Fishery Biology of Sillago muktijoddhai Collected from Cox’s Bazar Coast, the Bay of Bengal, Bangladesh

Sillago muktijoddhai is a marine fish found along the Bay of Bengal in Bangladesh and the coast of India. However, detailed information on its reproductive biology, length-weight relationship, and feeding habits is lacking. To fill this gap in literature, a research was conducted from August 2022 to October 2023, during which 444 individuals were collected from the Cox’s Bazar coast of the Bay of Bengal, Bangladesh. The total length and weight of the fish ranged from 51.23 to 200.5mm and 2.47 to 71.73g, respectively. Analysis of the sex ratio revealed a dominance of males over females, with a ratio of 1.36:1 (X² = 10.41, P< 0.05). The condition factors indicated that males exhibited a better growth pattern than females. The gonadosomatic index suggested that the peak breeding season occurs in November. Histological observations identified four distinct stages of gonadal development for males: immature, maturing, ripe, and spent. For females, the stages were immature, maturing, mature, and ripe. The absolute fecundity ranged from 6,164 to 30,555 eggs per ovary, with a mean value of 12,176 ± 1,050. The regression coefficient (b) for the length-weight relationship was 3.213, indicating a positive allometric growth pattern. Morphometric analysis of the mouth and relative gut length revealed that S. muktijoddhai is a bottom feeder with carnivorous habits. Gut content analysis showed that crustaceans formed the major component of its diet, although zooplankton, gastropods, bivalves, and sand were also present.