The present study examines the habitat suitability of three selected reaches of the Mathabhanga-Churni River in the wake of the declining river regime and escalating river water pollution. The study portrays the habitat degradation through the lens of the habitat suitability index (HSI) model based on four water quality (turbidity, pH, dissolved oxygen, and water temperature), three reproduction (pool velocity, riffle velocity, and riffle depth), and two food and cover (percentage vegetation cover and percentage pool) variables. Among the water quality variables, depletion in DO (0.4 mg/L) has become the most significant factor for fish habitat degradation. Reach-specific study of HSI reveals high habitat degradation for reach1 (RE1) and reach 2 (RE2) compared to reach 3 (RE3). The seasonality in HSI has also been reflected for all the study reaches. The value of HSI at RE1 depicts that 97.67% of samples of pre-monsoon season belong to the poor habitat category. Moreover, the study of fish species also reveals that the diversity and productivity have declined at a faster rate for RE1 and RE2 compared to RE3. For example, 29, 28, and 21 fish species have disappeared from RE1, RE2, and RE3 respectively since 1983. This typical habitat degradation is induced by lowering of discharge due to longitudinal disconnection of the Mathabhanga-Churni River from the Padma River due to the eastward tilting of the Bengal delta. Moreover, anthropogenic pollution such as discharge of industrial effluents, mixing of municipal sewage, pollutants from agricultural runoff are found to exacerbate habitat degradation. Finally, the study indicates few ways to restore the degraded fish habitat of the river.

本研究调查了马塔班加-库尔尼河三个选定河段在河势下降和河流水污染升级后的栖息地适宜性。该研究通过基于四种水质（浊度、pH、溶解氧和水温）、三种繁殖（水池流速、浅滩流速和浅滩深度）、和两个食物和覆盖（植被覆盖百分比和池百分比）变量。在水质变量中，溶解氧的消耗（0.4 毫克/升）已成为鱼类栖息地退化的最重要因素。针对 HSI 的特定区域研究表明，与区域 3 (RE3) 相比，区域 1 (RE1) 和区域 2 (RE2) 的栖息地退化程度较高。HSI 的季节性也已反映在所有研究范围内。RE1 的 HSI 值表明 97.67% 的季风前季节样本属于不良栖息地类别。此外，对鱼类物种的研究还表明，与 RE3 相比，RE1 和 RE2 的多样性和生产力下降速度更快。例如，自 1983 年以来，RE1、RE2 和 RE3 中分别有 29、28 和 21 种鱼类消失。这种典型的栖息地退化是由于 Mathabhanga-Churni 河与帕德玛河的纵向断开而导致排放量降低导致的。孟加拉三角洲向东倾斜。此外，发现工业废水排放、城市污水混合、农业径流污染物等人为污染会加剧栖息地退化。最后，