Jialin Liao’s research while affiliated with Xihua University and other places

Total dissolved gas supersaturation (TDGS) due to flood or hydropower station discharge adversely affects the swimming performance of migratory fish, thereby reducing passage efficiency. This study assessed the swimming performance of bighead carp in an experimental vertical slot fishway under varied slot flow velocities of 0.2, 0.25, and 0.3 m/s after 2 h of exposure to different levels of TDGS water. The results demonstrated that increased TDGS levels and flow velocities significantly reduced the fish passage efficiency. Specifically, passage success rates reached 61%, 48%, 37%, and 37% at TDGS levels of 100%, 110%, 120%, and 130% respectively, at a flow velocity of 0.2 m/s. At flow velocities of 0.2, 0.25, and 0.3 m/s with 100% TDGS water, success rates were 61%, 53%, and 47%, respectively. Moreover, increased TDGS levels and increased flow velocities notably extended the passage time in the fishway. Both TDGS levels and fishway flow velocities significantly influenced the swimming trajectories of the fish. Preferences for flow velocities were notably affected by the TDGS levels, whereas preferences for turbulent kinetic energy were affected by both the TDGS levels and the velocities of the fishway flow. In this study, an evaluation method was developed to assess the adverse effects of TDGS on fish passage efficiency based on the following critical parameters: passage success rate, time, trajectory, and preferred hydraulic factor. This study offers valuable insights for optimizing operations and fishway management to enhance fish protection.

During the flood season, high dam discharge rates result in total dissolved gas (TDG) supersaturation. This condition causes gas bubble trauma and can lead to fish mortality, which poses a significant threat to downstream river ecosystems. Assessing the ecological risks of TDG supersaturation is a challenge in waterpower-intensive river basins worldwide. Few studies have explored the impact of TDG supersaturation on fish behaviours, such as aggression and memory, which are crucial for feeding, reproduction, and predator avoidance. In this study, behavioural tests were conducted in a T-maze to investigate the effects of acute TDG supersaturation on swimming behaviour, aggression, and memory in medaka (Oryzias latipes). The results demonstrated that medaka exposed to TDG levels of 115% and 130% for 2 h had significantly reduced swimming performance.At TDG levels of 100%, 115% and 130%, medaka activity rates in the mirror arm of the maze in the mirror test were 44.34 ± 12.88%, 40.27 ± 15.44% and 35.35 ± 16.07%, respectively. Similarly, the activity rates of medaka in the active stimulus arm of the maze in the memory test were 50.35 ± 14.75%, 40.76 ± 12.51% and 35.35 ± 18.47%, respectively. The behaviour of medaka changed with increasing TDG supersaturation. These findings contribute to the development of an ecological risk assessment model for TDG supersaturation based on memory and aggression in fish and provide data for developing management strategies to mitigate the adverse effects of TDG supersaturation.

During the flood season, high dam operations for flood discharge result in total dissolved gas (TDG) supersaturation. This condition causes gas bubble trauma (GBT) and can even lead to fish mortality, posing a significant threat to downstream river ecosystems. Assessing the ecological risks of TDG presents a major challenge in water power-intensive river basins worldwide. Limited research has explored the impact of TDG on fish behaviors such as aggression and memory, which are crucial for feeding, reproduction, and predator avoidance. This study investigated the effects of acute TDG supersaturation stress on swimming behavior, aggression, and memory in medaka. Results indicated that Medaka exposed to 115% and 130% TDG supersaturation for 2 hours showed significantly reduced swimming performance. At TDG levels of 100%, 115%, and 130%, medaka displayed activity rates in the mirror arm of 44.34 ± 12.88%, 40.27 ± 15.44%, and 35.35 ± 16.07%, respectively, and in the active stimulus arm of 50.35 ± 14.75%, 40.76 ± 12.51%, and 35.35 ± 18.47%, respectively. As TDG levels increased, both aggression and memory in medaka significantly declined. The findings of this study could contribute to developing a TDG ecological risk assessment model based on fish memory and aggression, providing essential data for ecological management strategies to mitigate the adverse effects of TDG.