秋刀鱼(Cololabis saira)是西北太平洋温带海域的主要捕捞对象之一,也是西北太平洋渔业重要的组成部分。本研究根据北太平洋渔业委员会(NPFC)统计的2003~2017年渔获量数据以及中国秋刀鱼组织提交的单位捕捞努力渔获量数据(Catch per uni...秋刀鱼(Cololabis saira)是西北太平洋温带海域的主要捕捞对象之一,也是西北太平洋渔业重要的组成部分。本研究根据北太平洋渔业委员会(NPFC)统计的2003~2017年渔获量数据以及中国秋刀鱼组织提交的单位捕捞努力渔获量数据(Catch per unit effort, CPUE),基于贝叶斯Schaefer剩余产量模型,分基准方案和敏感性分析方案对西北太平洋秋刀鱼资源状况进行了评估,并对其管理策略做了风险分析。结果显示,基准方案和敏感性分析方案下模型参数预测值以及生物学参考点估计值比较相近。在基准方案下,估算的最大可持续产量(Maximum sustainable yield,MSY)为75.26×10^4 t,最大可持续产量的资源量BMSY为240.14×10^4 t,此时的捕捞死亡率为0.32。在敏感性分析方案下,估算的最大的可持续产量MSY为70.03×10^4t,最大可持续产量的资源量BMSY为232.53×10^4t,此时的捕捞死亡率为0.31。该海域秋刀鱼资源状况良好,未经受过度捕捞。风险评估分析表明,为使秋刀鱼资源可持续利用,需将捕获率设定在0.3左右。展开更多
Based on catch and effort data of tuna longline fishery operating in the South Pacific Ocean, the South Pacific albacore stock was assessed by an improved Schaefer model. The results revealed that the intrinsic growth...Based on catch and effort data of tuna longline fishery operating in the South Pacific Ocean, the South Pacific albacore stock was assessed by an improved Schaefer model. The results revealed that the intrinsic growth rate was about 1.283 74 and carrying capacities vareied in the range from 73 734 to 266 732 metric tons. The growth ability of this species is remarkable. Stock dynamics mainly depends on environmental conditions. The stock is still in good condition. However, the continuous decreasing of biomass in recent years should be noticed.展开更多
在Banach空间中研究一类具有Caputo-Fabrizio分数阶导数且在非局部条件下的脉冲分数阶微分方程解的存在性。利用Schaefer不动点定理,压缩映射原理,Arzela-Ascoli定理,得到了该脉冲分数阶问题至少一个解和唯一解,并用一个例子验证其中一...在Banach空间中研究一类具有Caputo-Fabrizio分数阶导数且在非局部条件下的脉冲分数阶微分方程解的存在性。利用Schaefer不动点定理,压缩映射原理,Arzela-Ascoli定理,得到了该脉冲分数阶问题至少一个解和唯一解,并用一个例子验证其中一个结论。The existence of a class of impulsive fractional differential equations with Caputo-Fabrizio fractional derivatives under non-local conditions is studied in Banach space. Based on Schaefer’s fixed point theorem, compression mapping principle and Arzela-Ascoli theorem, at least one solution and the only solution of the pulse fractional order problem are obtained, and one of the conclusions is verified by an example.展开更多
文摘秋刀鱼(Cololabis saira)是西北太平洋温带海域的主要捕捞对象之一,也是西北太平洋渔业重要的组成部分。本研究根据北太平洋渔业委员会(NPFC)统计的2003~2017年渔获量数据以及中国秋刀鱼组织提交的单位捕捞努力渔获量数据(Catch per unit effort, CPUE),基于贝叶斯Schaefer剩余产量模型,分基准方案和敏感性分析方案对西北太平洋秋刀鱼资源状况进行了评估,并对其管理策略做了风险分析。结果显示,基准方案和敏感性分析方案下模型参数预测值以及生物学参考点估计值比较相近。在基准方案下,估算的最大可持续产量(Maximum sustainable yield,MSY)为75.26×10^4 t,最大可持续产量的资源量BMSY为240.14×10^4 t,此时的捕捞死亡率为0.32。在敏感性分析方案下,估算的最大的可持续产量MSY为70.03×10^4t,最大可持续产量的资源量BMSY为232.53×10^4t,此时的捕捞死亡率为0.31。该海域秋刀鱼资源状况良好,未经受过度捕捞。风险评估分析表明,为使秋刀鱼资源可持续利用,需将捕获率设定在0.3左右。
文摘Based on catch and effort data of tuna longline fishery operating in the South Pacific Ocean, the South Pacific albacore stock was assessed by an improved Schaefer model. The results revealed that the intrinsic growth rate was about 1.283 74 and carrying capacities vareied in the range from 73 734 to 266 732 metric tons. The growth ability of this species is remarkable. Stock dynamics mainly depends on environmental conditions. The stock is still in good condition. However, the continuous decreasing of biomass in recent years should be noticed.
文摘在Banach空间中研究一类具有Caputo-Fabrizio分数阶导数且在非局部条件下的脉冲分数阶微分方程解的存在性。利用Schaefer不动点定理,压缩映射原理,Arzela-Ascoli定理,得到了该脉冲分数阶问题至少一个解和唯一解,并用一个例子验证其中一个结论。The existence of a class of impulsive fractional differential equations with Caputo-Fabrizio fractional derivatives under non-local conditions is studied in Banach space. Based on Schaefer’s fixed point theorem, compression mapping principle and Arzela-Ascoli theorem, at least one solution and the only solution of the pulse fractional order problem are obtained, and one of the conclusions is verified by an example.
