Population structure of Indian river shad, Gudusia chapra (Hamilton, 1822) from the Rupsha River, south-west Bangladesh

Abstract

The Indian river shad, Gudusia chapra, is a well-known species of potamodromous fish belonging to the Clupeidae family. The main focus of this study is to state the sex ratio, growth pattern, length-length relationship, form factor, Fulton’s condition factor and relative weight of G. chapra harvested from the Rupsha River (south-west Bangladesh). Altogether 300 specimens (male=166 and female=134) were harvested with the help of commercial fisher folks on seasonal basis (summer, rainy and winter) during 2022. Body weight and length of individual specimen were recorded with digital balance and measuring board. Total length varied between 12.7 to 16.5 cm for males and 13.0 to 17.3 cm for females. Further, body weight ranged between 15.82 to 42.48 g for male and 18.36 to 46.65 g for female. As a whole, both sexes revealed positive allometric growth pattern (b>3.00). Moreover, the length-length relationships were found highly correlated for both sexes. The estimated form factor was 0.0087 indicated fusiform body shape for G. chapra population. The mean Fulton’s condition factor was recorded close to 1 indicated a pleasant health condition for this species. Further, mean relative weight revealed a sound ecological atmosphere regarding prey-predator status. The research outcomes would be helpful to execute a sound management policy in the Rupsha River and connected ecosystem in the south-west Bangladesh.