DIETARY PREFERENCE AND SELECTION OF AN ENDANGERED SMALL-INDIGENOUS SPECIES CHELA Salmophasia bacaila (Hamilton, 1822) FROM THE DHEPA RIVER IN BANGLADESH

Abstract

The present study was investigated on environmental variability and gut contents of the chela fish (Salmophasia bacaila) from the Dhepa River in Bangladesh. Monthly sampling of fish and water quality parameters were performed at three different sites of Dhepa River from September 2017 to February 2018. It was found through PERMANOVA analysis that water temperature, dissolved oxygen and pH varied significantly among the months (PERMANOVA, P = 0.001). Water transparency showed spatio-temporal variation among the months and sites (PERMANOVA, P = 0.001) in the Dhepa River during the study period. Prey analysis determined 13 prey types from the gut contents of the chela fish. The prey species found in fish stomachs were highly dominated by phytoplankton (92.9%), while zooplankton contributed only 7.1% to the diets of chela. About 20 genera of phytoplankton and 7 genera of zooplankton were recorded from the gut of chela fish. PERMANOVA analysis showed a significant temporal (monthly) variation in the prey diversity of chela fish (PERMANOVA, P = 0.01). Overall, the results indicate that chela fish are predominantly plankton feeder. Changes in prey diversity can be predominantly influenced by the variation in abundance and distribution of preys that are likely regulated by the environmental factors in the Dhepa River. This study improves our understanding on the dynamics of key environmental drivers and prey selection of chela fish from a riverine system.