Page 193 - 《水产学报》2025年第7期

张金玉，等 水产学报, 2025, 49(7): 079514

Effects of light environment on behavioral traits and
upstream swimming activeness of juvenile Hypophthalmichthys molitrix

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ZHANG Jinyu 1,2,3 , SHI Xiaotao 1,2,3 , LIN Chenyu 1,2,3* , XIANG Lulu 1,2,3 , HUANG Jie ,
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SHI Shangshang , YANG Zijing 1,2,3 , LI Weidong 1,2,3 , WEI Lang 6
1. Hubei International Science and Technology Cooperation Base of Fish Crossing Dam Technology,
Three Gorges University, Yichang 443002, China;
2. Three Gorges Reservoir Ecological Environment Engineering Research Center, Ministry of Education,
Three Gorges University, Yichang 443002, China;
3. Institute of Fish Conservation, Three Gorges University, Yichang 443002, China;
4. Hubei Dangyang River Levee Management Bureau, Dangyang 444100, China;
5. Three Gorges New Energy Pumped Storage Power Generation (Golmud) Co., Ltd., Golmud 816000, China;
6. Power China Guiyang Engineering Corporation Limited, Guiyang 550081, China

Abstract: This study investigates the effects of phototaxis and behavioral traits of fish under different light conditions on their
upstream swimming activeness to facilitate fish migration past dams and improve the efficiency of fish passage facilities in
China. The experiment used juvenile Hypophthalmichthys molitrix, a key economic fish species in China, as the test subject. By
analyzing their phototaxis, stress degree, activeness, and light-oriented activeness under varying light wavelengths and illumin-
ance levels, we assessed how these factors influence upstream swimming activeness at different flow velocities. ① Under red
light, the preferred illuminance range for H. molitrix was 3.268-5.444 lx; under blue light, the acceptable illuminance range was
0.033-10.511 lx; under green light, the acceptable and preferred illuminance ranges were 0.367-74.489 lx and 3.776-9.833 lx,
respectively; under white light, no distinct preference or acceptable illuminance range was observed. ② The stress degree of H.
molitrix under red and green light initially increased and then decreased with rising illuminance, whereas under blue light, it
increased monotonically. The activeness of H. molitrix under red and green light increased steadily with illuminance, while
under blue light, it exhibited a fluctuating upward trend. ③ The upstream swimming tendency of H. molitrix was primarily
influenced by light preference and stress degree. When stress degree was low, upstream swimming activeness increased with
higher light-oriented activeness; conversely, when stress degree was high, upstream swimming activeness decreased as light-
oriented activeness increased. To optimize fish passage efficiency, we recommend: a 10 lx red light source at the facility
entrance can attract fish. Shaded areas inside the passage, combined with intermittent 1 000 lx green light sources, can promote
sustained upstream movement. Near hazardous turbine intake zones, a combination of 1 000 lx blue light and a 0.35 m/s flow
velocity can deter fish from approaching. This study provides theoretical and data-driven support for optimizing fish protection
engineering in various fish passage scenarios.

Key words: Hypophthalmichthys molitrix; light environment; flow velocity; upstream swimming efficiency; fish passage
Corresponding author: LIN Chenyu. E-mail: linchenyu@outlook.com
Funding projects: National Natural Science Foundation of China (52179070, 52279069)

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