基于复合种群的阿根廷滑柔鱼资源评估和管理策略评价

Stock assessment and management for metapopulation of Illex argentinus

以西南大西洋阿根廷滑柔鱼为例,利用基于贝叶斯统计方法的Schaefer模型分单一种群和复合种群2种种群方案,对其资源量进行评估,并对其管理策略做了风险分析。研究表明,年渔获量数据和资源丰度指数数据为贝叶斯资源评估模型提供了足够多的信息。单一种群方案和复合种群方案下的模型参数的预测值及估算的最大可持续产量接近,单一种群方案下的捕捞死亡率低于限制参考点F_(lim),复合种群方案下的南部种群存在捕捞死亡率大于限制参考点F_(lim)的年份,但随着捕捞死亡率的减小资源量恢复到良好水平。决策分析表明,在单一种群方案和复合种群方案下,当收获率设定为0.3及以下时,资源能够保持在可持续利用的良好水平,保守的管理策略可将收获率设定在0.2至0.3,相应的持续渔获量为80万t左右。

Stock assessment and management strategy evaluation of Illex argentinus was made based on metapopulation. Single population is the basic hypothesis for the present fishery stock assessment. However, resources are usually composed of several populations and communicate with each other, which can form metapopulation. In this paper, the abundance of I. argentinus is assessed based on Bayesian statistical Schaefer model with single population and metapopulation. The results showed that year capture data and resource abundance index could provide sufficient information for Bayesian stock assessment model. The estimated maximum sustainable yield is similar to prediction value of model parameters for both single population and metapopulation. Catch mortality is lower than Flim for single population, while catch mortality is higher than Flim for south metapopulation. Abundance recovers to good condition with decreased catch mortality. Decision analysis showed that the abundance could keep at sustainable level under single population and metapopulation with yield rate at 0.3. Yield rate should be set between 0.2 and 0.3 for conservative strategy, where the sustainable catch is around 0.8 million tons.