Abstract: The Chishui River is the last undammed first-order tributary of the upper Yangtze River Basin. It originates from the Wumeng Mountains in Zhenxiong County, Yunnan Province, and flows for nearly 437 km before drain into the upper Yangtze River in Hejiang County, Sichuan Province. Because of locating in the transitional region of the Yun-Gui Plateau and Sichuan Basin, habitat heterogeneity in the Chishui River is very high, ultimately leads to a rich biodiversity in both fish species and other aquatic organisms. Previous investigations revealed that the Chishui River inhabited 141 native fish species in its mainstream and tributaries, 46 of these species are endemic to the upper Yangtze River. It is widely expected that the Chishui River will play more important roles in fish conservation as the construction of cascade hydropower stations in low Jinsha River. In this paper, fish investigations were conducted in Chishui reach during the period from 2011 to 2013, in order to understand the present status of major commercial fish species in the Chishui River. Fish specimens were sampled monthly by a combination of different fishing gears, including fixed gill-nets, drift gill-nets, longline, shrimp pots and falling nets. A total of 58 fish species, belonged to 3 orders, 10 families and 47 genera, were collected during the study period. Among the species collected, Sinibrama taeniatus, Ancherythroculter kurematsui, Ancherythroculter wangi, Hemiculterella sauvagei, Hemiculter tchangi, Platysmacheilus nudiventris, Acrossocheilus monticolus, Bangana rendahli, Procypris rabaudi, Parabotia bimaculata, Leptobotia elongate, Sinogastromyzon szechuanensi, Liobagrus marginatoides were endemic to the upper Yangtze River. The fish assemblage was dominated by 13 species, namely Hemibarbus labeo, Spinibarbus sinensis,Saurogobio dabryi, Pelteobagrus vachelli, Mystus macropterus, Rhinogobio typus, Leiocassis crassilabris, Squalidus argentatus, Cyprinus carpio, Siniperca chuatsi, Pseudobagrus truncates, Carassius auratus and Silurus asotus, which collectively accounted for 92.61% (by amount) and 93.82% (by weight) of the total catches. Most individuals caught were small-sized with the body length <200 mm and the body weight < 100 g. Evident miniaturization tendency were detected in both fishing targets and fishing size compared to history data. Overfishing, water pollution, channel improvement and illegal dredging might be the main causes responsible for these changes. In order to effectively protect the Chishui River, which considered as the last refuge of endemic fish species, complete fishing closures and establishing of coordination management mechanism were suggested.

Key words: the Chishui River, fish resource, conservation