Abstract: Spawning ground is an important place for the survival and reproduction of aquatic organisms. At different stages of life history, Oncorhynchus keta has different requirements for environmental factors. Based on the data of water quality, hydrology and aquatic organism survey during the breeding, hatching and migrating period of salmon in the lower reaches of Huma River from autumn 2017 to spring 2018, we used the fuzzy membership function and analytic hierarchy process to standardize the calculation and weight assignment of the environmental indices of salmon spawning ground. We established the evaluation model of salmon spawning ground to compare the suitability across different seasons. The results of standardization showed that water quality and hydrological factors in the lower reaches of the Huma River could better meet the environmental requirements of salmon spawning grounds. Weight analysis results showed that water temperature, dissolved oxygen, and sediment were the most important factors affecting the suitability of salmon spawning grounds in the lower reaches of the Huma River, followed by ammonia, pH and water depth, in autumn, winter, and spring. The results of the evaluation model showed that the suitability index of salmon spawning grounds in autumn, winter and spring were 0.839, 0.652 and 0.743, respectively. Our results indicated that the eco-environment suitability of salmon spawning grounds in the study region was good, with the best in autumn, followed by spring, and worse in winter.

Key words: Daxing’an Mountains, vegetation phenology, eco-geographical region., GIMMS NDVI 3g