Page 299 - 《水产学报》2026年第04期

4 期 水 产 学 报 50 卷

Impact of extended fishing moratorium on life-history parameters of
different-sized fishes in the Bohai Sea via coupled aLBI-LBB methods

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LIANG Yaowei , SHAN Xiujuan , HAN Qingpeng , ZHAO Jie ,
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WU Qiang , LI Zhongyi , DAI Fangqun 1
(1. National Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries
Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China;
2. Fisheries College, Ocean University of China, Qingdao 266003, China;
3. Shandong Changdao Fishery Resources National Field Observation and Research Station, Yantai 265800, China;
4. College of Marine Living Resources Sciences and Management, Shanghai Ocean University, Shanghai 201306, China)

Abstract: The summer fishing moratorium (SFM) aims to protect spawners and larvae for fishery resource conservation. To
evaluate the conservation effectiveness of an extended SFM in the Bohai Sea, this study compared the population status and
biological parameters of fish species with different body shapes before and after the policy adjustment. Bottom trawl survey
data from late August were analyzed across two periods that before (2014-2016) and after (2017-2019) the SFM adjustment.
Nine representative species across six body shapes were selected: compressed (Konosirus punctatus, Thryssa kammalensis,
Engraulis japonicus, Sardinella zunasi), ribbon-like (Enedrias fangi), depressed (Callionymus beniteguri), eel-like (Chaeturich-
thys stigmatias), asymmetrical (Cynoglossus lighti), and fusiform (Scomber japonicus). Kernel density estimation was used to
compare length-frequency distributions. Allometric growth parameters b were analyzed using length-weight power functions.
Biological priors, including asymptotic length (L inf ), length at first maturity (L mat ), and optimum length (L opt ), were estimated
using the aLBI (a length-based indicators) method. The robustness of L inf estimates across different bin sizes (0.50–3.00 cm)
was measured by relative error (RE). Finally, L inf and L mat were used as priors for the LBB (length-based bayesian biomass)
model to estimate and compare resource indicators, such as relative biomass (B/B 0 ) and the ratio of natural mortality to growth
(M/K). Results showed significant differences in responses to the extended SFM among fish species. Body lengths showed an
increasing trend for T. kammalensis, S. zunasi, and K. punctatus, while a decreasing trend was observed for E. fangi, C. beniteg-
uri, C. lighti and S. japonicus. Changes in body length for C. stigmatias were not significant. The extension of the summer fish-
ing moratoria resulted in species-specific responses in the allometric growth parameter b. Specifically, for E. fangi, T. kam-
malensis, and E. japonicus the parameter b was significantly greater than 3 (P<0.001) across both periods, indicating positive
allometric growth. RE increased with larger bin sizes; for K. punctatus and C. beniteguri, RE increased and L inf was overestim-
ated when bin sizes exceeded 1.25 cm. B/B 0 showed an improving trend for K. punctatus, E. fangi, C. stigmatias, E. japonicus,
and S. zunasi, but declined for C. beniteguri, C. lighti, and S. japonicus. M/K values remained relatively stable, fluctuating
around 1.5 for most species. In conclusion, the effectiveness of the extended SFM varies by species, and assessment models are
highly sensitive to bin size settings. Practical applications should optimize bin sizes based on biological traits and sample sizes.
Although the extended SFM helps improve the population structure of pelagic fishes, the miniaturization of demersal fishes and
the insufficient spawning biomass in certain populations warrant further attention.
Key words: summer fishing moratorium; biological parameters; stock assessment; effectiveness evaluation; Bohai Sea
Corresponding author: SHAN Xiujuan. E-mail: shanxj@ysfri.ac.cn
Funding projects: National Key R & D Program of China (2024YFD2400405); Special Financial Project of the MARA for
Fishery Resources Survey in the Coastal and Offshore Waters of the Yellow Sea and Bohai Sea; Innovation Team of Fishery
Resources and Ecology in the Yellow and Bohai Seas (2023TD01)

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