基于LB-SPR和LBB模型的硇洲岛附近海域中华海鲇种群状态评估

Assessment of the population status of Tachysurus sinensis in the waters near Naozhou Island based on LB-SPR and LBB models

  • 摘要:
    目的 本研究旨在评估硇洲岛附近海域中华海鲇种群的资源状况与捕捞压力,为该区域渔业资源管理与可持续发展提供科学依据。
    方法 基于2016—2023年硇洲岛附近海域底拖网调查获得的中华海鲇体长频率与生物学样本数据(n=2614),采用LB-SPR和LBB两种模型对中华海鲇的繁殖潜力、捕捞压力与资源状态进行了综合评估。
    结果 中华海鲇von Bertalanffy生长参数渐进体长(L)为344.40 mm,LB-SPR模型估算的平均捕捞死亡率与自然死亡率比值(F/M)为5.60,繁殖潜力比(SPR)为0.02~0.03,显著低于常用限值参考点0.20与管理目标0.40,表明种群繁殖潜力已下降。LBB模型进一步指示,资源生物量比(B/BMSY)长期低于0.50,且开捕体长(Lc)远小于最适开捕体长(Lopt,238.43 mm),表明当前捕捞以小个体为主。
    结论 硇洲岛附近海域中华海鲇种群处于过度捕捞状态,且面临生长过度捕捞与繁殖潜力衰退双重问题。为实现种群的可持续利用,建议以提高渔具选择性与提升开捕体长为核心,推动Lc50逐步接近或不低于Lm50,并以SPR为核心构建捕捞控制规则,同时加强幼鱼与产卵栖息地保护。本研究可为数据有限条件下的底层鱼类资源评估与科学管理提供了参考。

     

    Abstract: Tachysurus sinensis is an important demersal fish species inhabiting the coastal waters near Naozhou Island, playing a key role in maintaining energy flow and ecosystem functioning within the sea. This study assessed the resource status and fishing pressure of the T. sinensis population in the waters near Naozhou Island, providing scientific evidence for fisheries resource management and sustainable development in the region. In order to assess the population status and fishing risks under limited data conditions, this study utilized length-frequency and biological sample data (n=2 614) obtained from bottom trawl surveys conducted in the waters near Naozhou Island from 2016 to 2023. Two models, the Length-Based Spawning Potential Ratio (LB-SPR) and the Length-Based Bayesian Biomass Assessment Model (LBB), were employed to comprehensively evaluate the reproductive potential, fishing pressure, and resource status of T. sinensis. The estimated von Bertalanffy growth parameter the asymptotic length (L) was 344.40 mm. The LB-SPR model estimated an average fishing-to-natural mortality ratio (F/M) of 5.60 and a spawning potential ratio (SPR) of 0.02~0.03, significantly lower than the conventional threshold reference point of 0.20 and the management target of 0.40, indicating a substantial decline in the reproductive potential of the population. The LBB model further indicates that the biomass ratio (B/BMSY) remained below 0.50 for most years, and the length at first capture (Lc) is much smaller than the optimal length (Lopt=238.43 mm), suggesting that indicating that the fishery selectively harvests immature individuals. The T. sinensis population in the waters near Naozhou Island is in a state of overfishing, facing the dual issues of growth overfishing and declining reproductive potential. The results suggest the coexistence of growth overfishing and declining reproductive potential. To achieve sustainable utilization of the stock, management measures should focus on improving fishing gear selectivity and increasing the minimum capture size. Efforts should be made to increase Lc50 to gradually approach or exceed Lm50, and fishing control rules should be established based on SPR reference points. Additionally, the protection of juvenile fish and spawning habitats should be strengthened. This study provides a scientific reference for the assessment and management of demersal fish resources under data-limited conditions.

     

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