基于贝叶斯Schaefer模型的西北太平洋柔鱼资源评估与管理

Stock assessment and management of Ommartrephes bartramii by using a Bayesian Schaefer model in the Northwestern Pacific Ocean

利用基于贝叶斯统计方法的Schaefer模型分均匀分布、正态分布和随机分布3种方案,对西北太平洋柔鱼资源量进行评估,并对其管理策略做了风险分析。研究认为,在均匀分布的基准方案下,参数r、K和q的后验概率分布与先验概率分布存在较大差异,这表明本研究采用的年渔获量和CPUE数据为贝叶斯资源评估模型提供了足够多的信息。正态分布和随机分布2种方案下模型参数的预测值及估算的最大可持续产量较接近,但小于基准方案。研究认为,3种方案下,1996—2004年捕捞死亡率都远低于限制参考点F0.1,1996—2004年渔获量也小于最大可持续产量,这表明目前西北太平洋柔鱼资源处于良好状况,没有遭受过度捕捞。决策分析表明,在相同的收获率情况下,基准方案得到的2019年资源量和渔获量均大于其它2种方案,但是资源崩溃的概率最大。保守的管理策略应将收获率控制在0.3左右,持续渔获量在13万t左右。

The stock assessment and risk analysis of alternative management strategies for neon flying squid Ommartrephes bartramii were carried out by using a Bayesian Schaefer model,in which three conditions,i.e.uniform,normal and random prior assumptions,are considered.Comparing the prior distributions of model parameters（e.g.r,K and q）with the posterior distributions,they differed greatly under the scenario of uniform prior assumption,indicating that the data provide enough imformation for the value of model parameters.The estimated model parameters and reference points were similar under the scenarios of normal and random prior assumptions,but less than the values under the scenario of uniform prior assumption.The fishing mortalities and total catches from 1996 to 2004 were lower than reference points F0.1 and MSY under three proposed scenarios,indicating that O.bartramii is on an expected sustainable exploited level and it is not in the state of over-fishing and over-fished.A stochastic decision-making framework was developed to incorporate the uncertainties in both the estimates of current fishing mortality（Fcur）and stock biomass（Bcur）and limited reference points of Flim and Blim.The results of decision analysis indicated that under the same harvest rate,the catch and biomass in 2019 from the uniform assumption are highest,which are more than that eatimated from the other two asumptions,but there is the highest probability of the collapse of squid resources.It is concluded that the harvest rate of 0.3 appears to be the best management regulation and the MSY will attain at 130 thousand tons,which balance the desire for high yields and the healthy population.