This study investigates the effect of weighting predictors on the performance of habitat suitability index (HSI) models using arithmetic mean (AMM) and geometric mean (GMM) methods. The case study focused on the catch data of Caspian Kutum (Rutilus frisii), with habitat parameters including day-time sea surface temperature, near-surface chlorophyll-a concentration, particulate organic carbon concentration, distance from fishing points to the river mouth, and bottom slope. Relative weights of environmental variables and suitability index (SI) fitting were determined using the support vector machine (SVM) technique. Sea surface temperature and particulate organic carbon concentration were identified as the most influential variables, with weights of 0.315 and 0.231, respectively, in explaining fish catch variance. Model performance evaluation revealed that the HSIWGMM model outperformed others, showing the lowest RMSE (training: 0.1818, testing: 0.2540) and the highest correlation coefficient (training: 0.4693, testing: 0.1953). In contrast, the HSIWAMM model showed the weakest performance (training: RMSE = 0.4023, r = 0.3843; testing: RMSE = 0.3858, r = 0.1360).