Abstract: Fish-based index of biotic integrity (F-IBI) has been widely used in the health assessment of rivers and lakes, which is of great significance for regional ecological restoration and protection. From October 2018 to July 2019, we sampled fish community in Shihoudian Lake, the experimental area of Baiyangdian Lake. Combing with FIBI and ABC curve (abundancebiomass comparison curves), we comprehensively evaluated fish community composition characteristics and water health status. A total of 30 species were recorded, belonging to 4 orders and 10 families. Cyprinidae had 21 species, accounting for 70% of the total number of fish species. The F-IBI evaluation results showed that three sites were evaluated as “good to excellent” in the Bai yangdian Lake experimental area, three sites as “good”, four sites as “general to good”, five sites as “general”, eight sites as “poor-general”, three sites as “poor”, and no sites as “excellent” or “extremely poor”. Overall, autumn and spring showed “generalgood”, and summer showed “poorgeneral”. The ABC curves revealed obvious crossover trend, indicating that the overall state and that both spring and summer were moderately disturbed. The abundance curve in autumn remained above the biomass curve, indicating that autumn was in a serious interference state. Compared with the period between 1950s and 1970s, F-IBI of Baiyangdian Lake showed a downward trend. Overfishing, water pollution, and extreme climate were important factors driving the changes of Baiyangdian fish communities. Fishing forbidden zone should be delimited and the closed fishing season should be extended to strengthen the protection and sustainable use of fish resources.

Key words: fish-based index of biotic integrity, abundance-biomass comparison curve, health assessment, Baiyangdian Lake.