Page 144 - 《水产学报》2026年第01期

1 期 石小涛，等：复杂变化水力环境下的草鱼稳定偏好水流速度 50 卷

Stabilized preferred flow velocity of Ctenopharyngodon idella under
complex dynamic hydraulic conditions

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SHI Xiaotao , BAO Chunpeng , WANG Yan , XU Xu , SU Xinyi , WU Shuai ,
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SONG Nianxiong , CHEN Xiaolong , SUN Junjian , WANG Yuanming , LI Minne 1,2*
(1. Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education,
China Three Gorges University, Yichang 443002, China;
2. Hubei International Science and Technology Cooperation Base of Fish Passage,
China Three Gorges University, Yichang 443002, China;
3. State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China)
Abstract: This study investigated whether Ctenopharyngodon idella exhibits a consistent range of preferred flow velocities
under complex dynamic hydraulic conditions. C. idella, a commercially important species in the Yangtze River Basin (total
length: 20.5-25.5 cm), was selected as the research subject. Laboratory experiments were conducted in an open recirculating
flume with variable-frequency control, where three characteristic flow scenarios were established. Each scenario consisted of
three parallel flow areas of equal width arranged along the streamwise direction. These areas represented all possible combina-
tions of three velocity levels (low, medium and high): Condition I (high-low-medium: 0.65-0.32-0.47 m/s), Condition Ⅱ (low-
high-medium: 0.27-0.78-0.48 m/s), and Condition Ⅲ (low-medium-high: 0.23-0.43-0.91 m/s). The upstream swimming
behavior of C. idella under three complex hydraulic conditions was comparatively analyzed by coupling fish trajectories with
background flow fields, and Boolean operations on probability density functions were applied to quantify the preferred flow-
velocity ranges of C. idella. The results showed that: ① fish residence time increased with decreasing flow velocity, indicating
a clear tendency to avoid high-velocity areas and prefer low to medium flow regions; ② under all conditions, C. idella predom-
inantly occupied areas adjacent to flume sidewalls where lower velocities prevailed, with preferred ranges identified as 0.40-
0.45 m/s and 0.60-0.67 m/s in Condition I, 0.41-0.50 m/s in Condition Ⅱ, and 0.18-0.31 m/s in Condition Ⅲ; and ③ when
background flow distributions were similar (Conditions I and Ⅱ), fish exhibited a stable preference for 0.41-0.45 m/s, whereas
under distinct flow regimes (e.g., Condition Ⅲ different from Condition I and Condition Ⅱ), preference shifted toward areas
with higher probability density and lower velocities. These findings indicate that C. idella consistently prefers low to medium
flow regimes, and C. idella has a stable preferred flow velocity under complex dynamic hydraulic conditions. This study
provides scientific reference to support the ecological design of fishways and flow restoration strategies tailored to the behavi-
oral responses of native fish species.
Key words: Ctenopharyngodon idella; complex changing flow field; preferred flow velocity; swimming behavior; fish conser-
vation
Corresponding author: LI Minne. E-mail: liminne@ctgu.edu.cn
Funding projects: National Natural Science Foundation of China Young Scientists Fund (52509100); Open Fund of the Engin-
eering Research Center for Eco-environment of the Three Gorges Reservoir Region, Ministry of Education (KF2022-10); Open
Fund of the State Key Laboratory of Mountainous River Protection and Control (SKHL2424)

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
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