Abstract:

Aims: Lugu Lake, a significant plateau deep-water lake in Southwest China, has not had its fish community reported in several years. 

Methods: This study conducted four field surveys in spring (May) and autumn (October) from 2023 to 2024. Redundancy analysis (RDA) and clustering methods were employed to elucidate the impact of environmental factors on the spatial and temporal diversity of fish communities. 

Results: A total of 14 fish species were identified, categorized into 2 orders, 4 families, and 14 genera, with Cypriniformes being the predominant Order (85.7%). The indigenous fish species found was the Misgurnus anguillicaudatus, while 13 exotic fish species were also recorded, constituting 92.86% of the total species, with Carassius auratus and Pseudorasbora parva being the most abundant. RDA analysis revealed that the fish community structure variation was influenced by NO_₃^⁻-N and pH in spring, and NO_₃^⁻-N and TN in autumn. The biomass curve in autumn, as indicated by the ABC curve, was notably higher than the abundance curve, illustrating an “autumn steady-spring metastable state” pattern. 

Conclusion: To address the challenges faced by the fish community in Lugu Lake, such as the decline of indigenous species and the prevalence of exotic species, it is recommended to focus on conserving indigenous fish, enhancing pollution control, regulating the release of exotic species, and establishing a comprehensive long-term monitoring program.

Key words: fish resources, community structure, diversity index, temporal and spatial variation