Affiliation:
1. School of Marine Biology and Fisheries Hainan University Haikou Hainan China
2. State Key Laboratory of Marine Resource Utilization in South China Sea Hainan University Haikou Hainan China
3. Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology Chinese Academy of Sciences Wuhan Hubei China
4. Department of Biological and Environmental Sciences Texas A&M University Commerce Texas USA
Abstract
AbstractLarge dams significantly impact river ecosystems by disrupting connectivity, altering physicochemical variables, and modifying flow regimes. These modifications influence the spatial and temporal dynamics of biological processes and species distributions. While much research has focused on potamodromous species, there remains a gap in understanding the recovery gradients of resident species in dam‐altered rivers. This study examines the responses of larvae of a resident species, the mandarin fish (Siniperca chuatsi), to environmental alterations caused by the Three Gorges Dam (TGD) in the middle reach of the Yangtze River. We hypothesized that larval abundance, feeding, growth, and survival would exhibit longitudinal recovery gradients, improving with the increased distance from the TGD. Our results confirm this hypothesis, showing that larvae further from the TGD exhibited higher abundance, increased feeding intensity, enhanced growth rates, improved survival rate, and earlier peak abundance and hatching dates. Key environmental factors, including water temperature and discharge, increased downstream, while transparency decreased. Major tributary inputs significantly contributed to these recovery gradients. The observed longitudinal gradients in larval attributes mirrored environmental changes, underscoring the TGD impact on population recruitment. These results highlight the broader implications of dam‐induced changes on resident species recruitment, potentially affecting entire fish communities. Our study contributes to understanding the distinct spatial patterns of population trends, providing valuable insights for designing more effective conservation and management practices for resident freshwater fishes in large regulated rivers.
Funder
National Natural Science Foundation of China
National Key Research and Development Program of China
Education Department of Hainan Province