Abstract: As Dongting Lake is one of the two biggest lakes still linked with the Yangtze River, its fish resource study becomes important and valuable for the evaluation of lakes in the river basin. Therefore, a monthly survey of fish resource was carried out from September 2002 to June 2004. 111 species belonging to 9 orders and 21 families were recorded, including some cherish and rare species, e.g. Acipenser sinensis Gray, and Myxocyprinus asiaticus. The number of fish species varied within the year, with the highest number 69 species, the lowest 26. The dynamics of diversity index matched well with the number of species, with its fluctuation being relatively even at an average of 2.84±0.38. The number of species and then diversity in connecting areas with water flowing into lakes were higher than those in opening water areas of the lake. The limnicolous fishes accounted for over 50% of individual fishes, among which the common carp Carassius auratus auratus was the most abundant, accounting for 16%. In conclusion, as a linking lake, west Dongting Lake acts as shelter and intercourse grounds for fishes and is a place for the protection and restoration of fish diversity in the lake and also in the Yangtze River. The fact that the percentage of limnicolous fishes increased over recent years at west Dongting Lake should be considered in any project in order to protect the natural fish resource in the lake and also in the river.

Key words: West Dongting Lake, fish diversity, spatiotemporal variation, linking lakes