Abstract:This research investigated the resources of Neosalanx taihuensis, and Hemisalanx brachyrostralis in the Xiangxi River, a tributary to the Three Gorges Reservoir. Sampling was conducted at at four sites (i.e. Xiakou, Yanguan, Qiaojiaba and Guanzhuangping) in the river during October 2006 and October 2007. At Xiakou, Yanguan and Qiaojiaba, The number of individuals of N. taihuensis and H.brachyrostralis was counted for 3 to 5 fishmen's daily harvest every quarter, i.e. in October 2006, January, April, July, and October 2007; while at Guanzhuangping, the icefish was collected at three water depths in the column, i.e 5 m, 10 m and 15 m respectively. Sampling was conducted using a lift net (area: 15 m × 15 m; mesh size: 2-3 mm) 2 or 3 times each month. During sampling, the major physical and chemical factors of the water were measured. Growth characteristics of N. taihuensis and H. brachyrostralis were analyzed. The results showed that (1) The average water temperature from January through March is 8.4℃ for many years in the Xiangxi River; The average minimum water temperature in February was 5.9℃ for years. The season with the water temperature suitable for the incubation of ice-fish was between December and March. (2) The pH of Xiangxi River ranged from 7.5 to 9.5 around the year, and is usually about 8.5, which is good for reproduction and growth of both species. (3) The contents of major nutrition varied among the sampling sites, and could basically support the growth of ice-fish. (4) Individuals of 5-6 cm standard length accounted for 96.2% of the harvest of N. taihuensis. The fullness index of N. taihuensis and H. brachyrostralis are (0.004±0.0004) g/cm3 and (0.002±0.0003) g/cm3 respectively, which was significantly different between the two species (P<0.001). Spatial pattern of the populations and the impacts of fishery harvest and fishing intensity on population dynamics of both species were also discussed. (1) The N. taihuensis and H. brachyrostralis live in all the tributaries in the Three Gorges Reservoir in Hubei Province. Abundance declined gradually upward along each stream. N. taihuensis is dominant compared to H. brachyrostralis in the harvest. (2) The applying of lift net using light to trap ice-fish has induced dramatically decline of ice-fish abundance, and changed the size structures of the populations. In October 2006, the percentages of individuals in 50-60 mm, 60-70 mm and larger than 70 mm standard length in the catch of N. taihuensis were 62.3%, 20.6% and 14.7% respectively; and in October 2007, the percentages were 20.2%, 61.7% and 15.8% respectively. With the increase of fishing intensity, the spawning stock diminished in size structure and declined in abundance., which indicated decline of the N. taihuensis population from overexploitation. (3) The water temperature in the water column from the surface to 10 meter depth is usually constant in most seasons in the Xiangxi River. The N. taihuensis spreads across this water column. While during June through August, water temperature is high in the surface, and the N. taihuensis lives mainly in the water depth between 5 and 10 m, indicating the avoidance of high temperature by N. taihuensis. Water near the rock bank in the river is usually clean with high transparency, where density of ice-fish is usually high.