Spatial and temporal variations of fish assembly with environmental parameters from two major rivers in Dinajpur district of Bangladesh

The study examined habitat and seasonal variations of fin fish structure and ecological parameters in the Atrai and Dhepa Rivers, Dinajpur, Bangladesh. The researchers collected data from four sampling stations, revealing 15532 individuals from 44 genera and 59 species. Pethia ticto, Chanda nama, Cirrhinus reba, Puntius sophore, and Salmophasia bacaila were recorded as dominated fishes (>4.95%). The fish population was highest in autumn at Mohonpur (MP), while lowest in the monsoon at Karnai Bazar (KB). There were no significant variations across stations for rainfall, dissolved oxygen, pH, transparency, air and water temperatures, and pH. However, significant differences were observed among seasons based on all factors. The study also revealed differences in dominance, Margalef, Shannon, and evenness diversity indices spatiotemporally, except for evenness diversity indices among seasons. The findings could be useful for conservation studies in the future, especially after establishing and managing restricted areas like fish sanctuaries in both rivers. Bangladesh J. Sci. Ind. Res. 59(2), 55-66, 2024