Page 148 - 《水产学报》2025年第7期

刘啟庆，等 水产学报, 2025, 49(7): 079511

Flow tolerance of juvenile Lateolabrax maculatus

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LIU Qiqing , HUANG Liuyi , LUO Yan , LIU Xiao , LIU Bo ,
WANG Run , BI Chunwei , YOU Xinxing
College of Fisheries, Ocean University of China, Qingdao 266003, China

Abstract: Sea cage aquaculture is an important industry for marine fish production in China. With the compression of offshore
cage farming space and the requirements of ecological and environmental protection, the development of deep-sea cage culture
is an inevitable trend to promote the high-quality development of mariculture industry. Flow velocity has an important impact
on fish behavior, physiology and growth. Studying the swimming performance of fish is of great significance for the optimal
stocking specifications of deep-sea aquaculture species, improving the design and operation of aquaculture facilities, and pro-
moting the high-quality and orderly development of deep-sea aquaculture. Lateolabrax maculatus is an important aquaculture
species in offshore and deep-sea cages in northern China. However, due to its own swimming ability research and the influence
of flow on its swimming behavior is not clear, it is impossible to provide scientific basis for the site selection, breeding equip-
ment design and stocking specifications of deep-sea cages for the fish. To evaluate the flow tolerance of juvenile Lateolabrax
maculatus, this study investigated critical swimming speed (U crit ), burst swimming speed (U burst ), endurance swimming time,
and their correlations with 14 morphological traits using a fish behavioral experimental circulating flume with specimens of
(9.61±0.74) cm body length. Through ethological research methods, we analyzed tail beat frequency, swimming states, and
swimming trajectories under varying velocities. Results demonstrated that absolute U crit and U burst were (0.69±0.05) m/s and
(0.86±0.05) m/s respectively, while relative values reached (7.12±0.4) BL/s and (9.09±0.48) BL/s (BL represents the body
length of experimental fish, BL/s indicates the swimming speed in body lengths per second). The endurance swimming time
was measured (200.83±45.73) min at 0.6 m/s, but showed dramatic decline at 0.7 m/s. Significant positive correlations (P<0.05)
were identified between swimming performance (absolute U crit and U burst ) and most morphological traits, except for first dorsal
fin length, second dorsal fin length, ventral fin length, and caudal fin length (P>0.05). Tail beat frequency exhibited significant
positive correlation with velocity (P<0.05). When the flow velocity was ≥ 4 BL/s, the relative swimming distance of Lateolab-
rax maculatus decreased significantly, the proportion of countercurrent forward swimming time decreased significantly, the
proportion of countercurrent static swimming time increased, and the proportion of downstream backward time decreased with
the increase of flow velocity. The swimming area of the experimental fish was reduced, and it could only move in the corner of
the flume at high flow velocity (6 BL/s). Based on swimming performance analysis, we recommend considering partial mor-
phological traits (tail length, head length, and trunk length) alongside body length for stock selection. For juvenile L. maculatus
aquaculture facilities, maximum flow velocity should not exceed 6.24 BL/s, while behavioral considerations suggest maintain-
ing velocities below 4 BL/s. The results of this study can provide a reference for the site selection of sea cage aquaculture, the
design and construction of breeding facilities and the determination of stocking specifications of L.maculatus farming.
Key words: Lateolabrax maculatus; critical swimming speed; burst swimming speed; endurance swimming time; morpholo-
gical traits; swimming behavior
Corresponding author: HUANG Liuyi. E-mail: huangly@ouc.edu.cn

Funding projects: National Key Research and Development Program of China (2024YFD2400300); Qingdao Marine Science
and Technology Innovation Demonstration Project (23-1-3-hysf-2-hy)

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