A multidisciplinary approach to study the feeding behavior of Grey-eel catfish (Plotosus canius) in exploring the blue economy of the Bay of Bengal

Abstract

The feeding ecology of fish is closely related to its population dynamics, and knowledge can help to understand resource allocation, habitat preferences, prey selection, predation, evolution, competition, and the transfer of energy within and between ecosystems. Therefore, this research aimed to examine the data on the feeding habits of a commercially important catfish, Plotossus canius from two different regions (Chattogram and Cox’s Bazar) of Bangladesh. The live fish were collected from the local fishermen and gut content was assessed and different gastrointestinal indices like visceral somatic index (VSI), hepatosomatic index (HSI), intestine somatic index (ISI), condition factor (K), relative condition factor (Kn), and relative length of gut (RLG) were measured. Gut content analysis showed that crustaceans (45%), bivalves and mussels (36%), arthropods, and isopods (11%) were the dominant food items in P. canius. Measured gastrointestinal indices revealed that fishes from the Chattogram region had significantly higher VSI, HSI, ISI, K, and Kn values compared to the fishes from the Cox’s Bazar region. Histologically, it was observed that the villi of the intestine are longer and more branching in the anterior part of the gut than they are short and unbranched in the posterior part. At the indoor level, P. canius preferred crab meat compared to the marcel (mixture of clam and mussel muscle) and trash fish (tilapia). The findings of the present study may be helpful for understanding the food and feeding habits as well as in improving the domestication and culture of this species in the future of this commercially important fish species