This investigation characterized the relationship between percentage occurrences of three size classes of Hilsa juveniles (3–5, 5.1–10, and 10.1–15 cm) and six biogeochemical parameters (water temperature, chlorophyll-a, turbidity, salinity, dissolved oxygen, and pH) in the lower part of the tidal riverine to the entire estuarine stretch of Hooghly. These relationships helped us determine the ranges of each biogeochemical parameter for different suitability criteria in three seasons, pre-monsoon (February–May), monsoon (June–September), and post-monsoon (October–January). Salinity had the highest weight (0.37–0.39) followed by chlorophyll-a (0.26–0.30) and turbidity (0.12–0.20). The geospatial data of the biogeochemical parameters were interpolated followed by reclassification with the suitability ranges, separately for each season. These reclassified data were integrated into GIS-based modeling by a multi-criteria decision-making technique (analytical hierarchy process) to generate the habitat suitability maps of juvenile Hilsa. The model-derived information was verified with the indigenous knowledge of the fishers regarding the suitable habitat of juvenile Hilsa by conducting group discussions at 13 locations along the entire study area. The degree of agreement/disagreement between the model and the field information was determined by measuring Kendall’s tau (0.81–0.96) and Kappa coefficients (0.77–0.86), which indicated a strong agreement. In total, 3.80%, 10.12%, and 31.08% of the total river-estuarine area considered for the present study were identified as highly suitable for juvenile Hilsa during pre-monsoon, monsoon, and post-monsoon seasons, respectively. This mapping can act as baseline information for the policymakers for sustainable Hilsa fishing keeping in view the livelihood of fishers.

该调查描述了三种体型的 Hilsa 幼鱼（3-5、5.1-10 和 10.1-15 厘米）的出现百分比与六个生物地球化学参数（水温、叶绿素a、浊度、盐度、溶解氧和pH 值）在潮汐河流的下部到整个胡格利河口段。这些关系帮助我们确定了三个季节中不同适宜性标准的每个生物地球化学参数的范围，即季风前（2 月至 5 月）、季风（6 月至 9 月）和季风后（10 月至 1 月）。盐度过之后叶绿素最高重量（0.37-0.39）一(0.26–0.30) 和浊度 (0.12–0.20)。对生物地球化学参数的地理空间数据进行插值，然后根据适宜性范围对每个季节分别进行重新分类。这些重新分类的数据通过多标准决策技术（层次分析过程）集成到基于 GIS 的建模中，以生成幼鱼 Hilsa 的栖息地适宜性图。通过在整个研究区域的 13 个地点进行小组讨论，利用渔民关于幼鱼 Hilsa 适宜栖息地的土著知识验证了模型得出的信息。通过测量 Kendall's tau (0.81–0.96) 和 Kappa 系数 (0.77–0.86) 来确定模型与现场信息之间的一致/不一致程度，这表明一致。总共 3.80%、10.12% 和 31。本研究考虑的河流河口总面积的 08% 被确定为分别在季风前、季风和季风后季节非常适合幼年 Hilsa。该地图可以作为决策者的基线信息，以实现可持续的 Hilsa 捕鱼，同时考虑到渔民的生计。