Abstract:

In order to understand the invasion status and hazards of alien fishes in three major rivers of Fujian, from March to April 2023, 10 sites were sampled in the west branch of Jiulongjiang River, Zhangjiang River and Tingjiang River to investigate the species composition, quantity, and distribution of alien fishes by using flow gill nets and ground cage nets. The degree of harm was evaluated based on weight proportion of alien fishes in the catches. The survey results showed that there were 7 species of alien fishes, including Coptodon zillii, Sarotherodon galilarea, Oreochromis niloticus, Parachromis managuensis, Pterygoplichthys pardalis, Clarias gariepinus, and Labeo rohita. The species number of alien fishes in the three rivers was 6, 5, and 2, with a quantity proportion of 58.97%, 81.35%, and 45.22%, and a weight proportion of 65.53%, 82.52%, and 41.28%, respectively. Alien fishes had distributed in the three rivers and became the main group of fishes, with the majority being tilapia such as C. zillii, S. galilarea, and O. niloticus. The degree of harm caused by alien fishes in all three rivers was high. This study investigated the invasion status of alien fishes in rivers, providing basic data support for the protection of fish diversity and the prevention and control of alien invasive species.

Key words: major rivers of Fujian, invasion of alien fishes, hazard assessment