基于LIME模型的海州湾小眼绿鳍鱼资源评估

Stock assessment of Chelidonichthys spinosus in Haizhou Bay based on the length-based integrated mixed effects model (LIME)

  • 摘要:
    目的 本研究旨在利用基于体长的集成混合效应模型(LIME),对数据有限的海州湾小眼绿鳍鱼资源状况进行评估,并对模型关键参数进行敏感性分析。
    方法 本研究利用2013—2023年海州湾渔业资源调查获取的小眼绿鳍鱼体长频率数据,运用LIME模型评估了该种群的捕捞死亡系数和相对生物量等参数。通过对参数hM分别设置±25%的误差,以及构建短时间序列开展了模型的敏感性分析,评估产卵潜力比SPR及捕捞死亡系数F的变化,利用平均相对误差(MRE)指标反映了评估结果受影响的大小。
    结果 2013—2023年海州湾小眼绿鳍鱼的捕捞死亡系数较高(F=2.09−2.72),显著高于其生物学参考点F30=0.81。其补充量呈波动下降趋势,产卵潜力比SPR范围为 0.106~0.129,表明资源已处于过度利用状态。敏感性分析表明,自然死亡系数M对评估结果影响显著,而陡度h的影响较小。时间序列的长度对LIME模型的估算结果有重要影响,且对捕捞死亡系数F的影响大于SPR。
    结论 海州湾小眼绿鳍鱼资源已处于过度捕捞状态。LIME模型能够利用体长频率数据评估资源开发状态,但对自然死亡系数和数据时间长度等条件的敏感性较高,使用时需谨慎估算相关参数并考虑鱼种生活史特性和数据适用性。

     

    Abstract: Driven by environmental changes and fishing pressure, the stock status of Chelidonichthys spinosus has changed significantly in Haizhou Bay in recent years. However, due to the lack of data such as yields and fishing efforts, stock assessments are challenging for this species and the status of fishery exploitation remains unclear. In this study, we used length-frequency data obtained from the fishery surveys in Haizhou Bay from 2013 to 2023 to assess the stock status of C. spinosus using the Length-based Integrated Mixed Effects (LIME) model which is based on non-equilibrium assumptions. The uncertainty of the LIME model was further considered, and sensitivity analyses were conducted on parameters such as the steepness(h) in the stock-recruitment relationship, the natural mortality coefficient(M), and the length of the time series data. The results showed that the fishing mortality coefficients of C. spinosus were relatively high (F = 2.09 - 2.72) in Haizhou Bay from 2013 to 2023, significantly exceeding the biological reference point F30 = 0.81. Recruitment of C. spinosus showed a fluctuating and declining trend, with the spawning potential ratio (SPR) ranged from 0.106 to 0.129, indicating that the stock was heavily overfished. The sensitivity analysis showed that the natural mortality coefficient (M) had a significant impact on the assessment results, while the impact of the steepness (h) was relatively small. The length of the time series had a significant effect on the estimation results of LIME, with a greater impact on the bias of F than on SPR. We highlight that LIME is capable to assess the stock status based on length-frequency data and is suitable for data-limited fisheries; however, it is sensitive to parameters such as natural mortality, and caution should be taken when the model is implemented in practice, regarding the estimation of critical parameters, the life history characteristics of target species, and the feasibility of survey data.

     

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