Abstract:

To understand the status of fish species diversity and seasonal variation in the Chaozhou section of Hanjiang River, a survey was carried out at five sample sites using fixed gillnets and cage nets from May 2012 to April 2013. In this study, 53 fish species, belonging to 8 orders, 19 families and 48 genera, were collected. Results indicated that Cypriniformes and Perciformes were the dominant groups with 27 and 11 species and accounting for 50.9% and 20.8% of the total species, respectively. Compared with earlier research, there were 13 new species recorded. The dominant species were Megalobrama terminalis, Microphysogobio fukiensis, Squaliobarbus curriculus and Cirrhinus molitorella, which accounted for 65.78% of the total samples. Shannon-Wiener index (H′), Pielou’s evenness index (E′) and Margalef richness index (D) were the highest in summer, followed by those in autumn, winter, and spring; Simpson index (D') was the highest in autumn, followed by those in summer, winter, and spring. A cluster analysis and non-metric multi-dimensional scaling ordination of Bray-Curtis similarity data based on species and abundance showed that the 12 months could be divided into 2 groups at a 38.23% similarity level, i.e. group I comprised six months of summer and autumn, while group II comprised six months of spring and winter, which is consistent with the variations in the diversity indices H', E, D and D'. These results indicated significant seasonal variations in fish resources among seasons. Water temperature and flow were suggested as the key drivers on fish resources in this area. Based on their appearance, 10 major fish species can be divided into two groups; Group A was characterized by small fish that appeared seasonally, while group B contained common species. In addition, it proposes that the habitat protection and the establishment of appropriate fishing regulations are the key measures to protect fish stocks in the Chaozhou section of Hanjiang River.

Key words: Hanjiang River, fish resources, community dynamics, new record, cluster analysis