Comparative Assessment of Gastrointestinal Indices and Feeding Habits among Three Species of Jew Fish from the Bay of Bengal, Bangladesh

Abstract

The Bay of Bengal (BoB) is one of the rich marine ecosystems with diverse fish species. Croakers, also known as jewfish are economically important fish species in the BoB. However, very little is known about the life-history traits of the croaker from the BoB. In this study, a total of 105 samples of croakers were collected during the months of September - October 2021 and September-October 2022 from the coast of Dorianogor jele polli of Cox’s Bazar and an extensive analysis of biological indices and feeding habits was conducted on three croaker species - Johnius borneensis, Otolithes ruber and Johnius belangerii. The total length and total weight of the individual sample along with the length and weight of the targeted internal organs were measured to calculate gastrointestinal indices and RLG values. Results found significant variations in these gastrointestinal indices like visceral somatic index (VSI), hepato somatic index (HSI), intestine somatic index (ISI), relative length of gut (RLG) and gonado somatic indices (GSI) values among the studied croaker species. Results showed that J. borneensis exhibited the highest VSI, indicating superior energy storage compared to other species. The HSI values also demonstrated significant difference highlighting distinct nutritional requirements and metabolic activities among the croaker species. In addition, the dietary preferences of the croaker species were investigated through gut content analysis and also found variations in the food compositions and amount of food among three closely related croaker species. The findings of the present study will provide a baseline for valuable insights into the nutritional health, feeding behaviors and reproductive patterns of these croaker species, contributing to a better understanding of their ecological roles in the Bay of Bengal.