Limnological Variations and its Effect on Biodiversity of Freshwater Bund Khushdil Khan Dam, District Pishin Quetta Balochistan.

A B S T R A C T This study investigated the seasonal limnological variations and their impact on freshwater biodiversity in Bund Khushdil Khan Dam, District Pishin, Balochistan, from July 2024 to June 2025. Monthly water samples were collected and analyzed for key physico-chemical parameters, including temperature, turbidity, total dissolved solids (TDS), pH, dissolved oxygen (DO), biological oxygen demand (BOD), electrical conductivity (EC), and salinity, following standard APHA methods. Seasonal fluctuations were evident across most parameters: turbidity and TDS peaked during the monsoon, while DO levels were highest in summer and lowest in winter. These variations significantly influenced aquatic biota, particularly zooplankton abundance and biomass. The findings highlight that Bund Khushdil Khan Dam supports biodiversity but faces water quality challenges due to seasonal fluctuations, which may affect fisheries and local water use. Continuous monitoring and management are recommended to maintain ecological balance and ensure sustainable utilization of this freshwater resource