Abstract
The main objectives of this study were to determine how the weir affect spatial and seasonal distribution of fish assemblages and physicochemical water quality as well as chemical and biological health. Summer monsoon was the key determinant in regulating the weir discharge. It regulates the concentration of total phosphorus and total suspended solids in the downstream weir. The water temperature, concentrations of chlorophyll and chemical oxygen demand were increased due to habitat alterations from running to stagnant type. The relative abundance of tolerant fish was the highest in 2012, 2013 and 2014 during spring and fall but in 2017, the relative abundance of intermediate species was the highest during fall only. The constancy value was the highest for tolerant and exotic fish species whereas sensitive and herbivore fish species were disappeared. Due to the construction of weir, the migration of fishes has been disrupted. Therefore, the abundance of lentic type fish species has been increasing whereas lotic type fish species were on the decline. The overall abundance of omnivores and herbivores were dominant in whole study domain. Moreover, the chemical and biological health was in very poor and poor condition, respectively.
Get full access to this article
View all access options for this article.