Two hypogean species of genus Triplophysa are herein described from two subterranean tributaries of the River Yangtze drainage in Guiyang City, Guizhou Province, China. Triplophysa wudangensis, new species, can be distinguished from its congeners by the combination of the following characters: eye reduced, with diameter 5.1-6.5% HL; interorbital width 33.1-35.8% HL; body scaleless; lateral line complete; posterior chamber of air bladder degenerated; anterior nostril with elongated barbel-like tip; distal margin of dorsal fin truncate; dorsal fin with 7, anal fin with 5, and caudal fin with 14 branched fin rays; vertebrae 4 + 34. Triplophysa qingzhenensis, new species, can be distinguished from its congeners by the combination of the following characters: eye reduced, with diameter 2.1-4.4% HL; interorbital width 25.1-30.4% HL; body scaleless; lateral line complete; posterior chamber of air bladder degenerated; anterior nostril with elongated barbel-like tip; distal margin of dorsal fin truncate; dorsal fin with 7-8, anal fin with 5, and caudal fin with 14 branched fin rays; vertebrae 4 + 36. Molecular phylogenetic analysis supported the validity of these two new species and indicated their close relationship with Triplophysa rosa.

Background: To rehabilitate the depleted fish resources of the Yangtze River Basin, China, a 10-year fishing ban has been implemented. This national initiative has attracted worldwide attention. The present study aimed to explore the ecological process and recovery effectiveness of this complete fishing ban in the Chishui River, the first river where the fishing ban was enacted in the Yangtze River Basin. Changes in fish resources were analyzed based on investigations conducted 5 years before (2012–2016) and 5 years after (2017–2021) the implementation of the fishing ban in four reaches along the longitudinal gradient. Results: A total of 140 fish species, including 127 native and 13 exotic species, were collected during the study period. The number of fish species as well as the diversity indices showed no significant temporal changes. However, 11 native species that had disappeared for many years appeared again after the fishing ban. The occurrence rates of some key protected species, Procypris rabaudi, Acipenser dabryanus, Euchiloglanis davidi and Myxocyprinus asiaticus, increased after the fishing ban, while Coreius guichenoti, Percocypris pingi, Onychostoma angustistomata and Leptobotia rubrilabris showed no obvious recovery. The fish assemblage structure in nearly all reaches (except the headwater) showed significant temporal changes with an increase in the relative abundance of larger body-sized species. The population structure of most dominant species improved greatly with the mean standard length and the mean body weight as well as the proportion of larger-sized individuals clearly increasing. In addition, the density of fishes changed dramatically with the catch per unit effort (CPUE) increasing by 140–210% for different study reaches. Conclusions: The present study confirmed that the complete fishing closure is an effective measure to facilitate fish resources recovery. These results provide valuable references for evaluating the effectiveness of the 10-year fishing ban policy in the entire Yangtze River.

Knowledge of food resource partitioning among sympatric fish species is crucial for understanding the potential mechanisms of species coexistence. Gudgeons (Teleostei: Cyprinidae: Gobioninae) often dominate fish assemblages in the upper Yangtze River. However, little research has been conducted on their trophic interactions. In this paper, seasonal diet and feeding strategy variations of four sympatric gudgeon species,Coreius guichenoti,Coreius heterodon,Rhinogobio ventralis,andRhinogobio cylindricus, were investigated by analysis of intestinal tract contents, aiming to explore whether food resource partitioning occurred among them. Fish specimens were collected during spring (April–May) and autumn (August–October) in 2010 in Hejiang, a free‐flowing stretch of the upper Yangtze River.Coreius guichenoti,C. heterodon,andR. cylindricusshowed omnivorous feeding habits, whileR. ventralisexhibited an obligate carnivore feeding habit. Diet overlap among the four studied species was high, especially in spring. However, changes in feeding strategies were observed in autumn. Specifically,C. guichenotiandR. cylindricusexpanded their dietary niche breadth and consumed detritus, Sinopotamidae or Hydropsychidae as important complementary food resources. In contrast,C. heterodonandR. ventralisreduced their dietary niche breadth and became more specialized on mussels (Limnoperna lacustris). These results confirmed that sympatric fish species can coexist with high diet overlap, and food resource partitioning among these species may also fluctuate with the seasons.