海洋中尺度涡对南太平洋长鳍金枪鱼延绳钓渔获量的影响

Effects of oceanic mesoscale eddies on longline catches of Thunnus alalunga in the South Pacific Ocean

摘要:

为了探索南太平洋中尺度涡对长鳍金枪鱼（Thunnus alalunga）渔获量的影响模式,揭示不同类型涡旋与南太平洋长鳍金枪鱼延绳钓渔获量的相关关系,基于涡特征环境数据利用EddyNet深度学习模型自动检测识别南太平洋中尺度涡,结合渔业探捕数据,分析捕捞站点到涡边缘及涡中心的相对距离对长鳍金枪鱼单位捕捞努力量渔获量（Catch per unit effort,CPUE）的影响。结果显示,南太平洋反气旋涡数量通常多于气旋涡,同时半径大于气旋涡。气旋涡和反气旋涡均显示,随着捕捞站点到最近涡边缘外侧的相对距离的增加,长鳍金枪鱼CPUE均呈下降趋势。在涡扰动区域内,反气旋涡的CPUE高于气旋涡,且随着捕捞站点到涡中心相对距离的增加,CPUE逐渐减小。研究表明,中尺度涡相较于背景场对渔获物产量具有积极的调控作用,且反气旋涡和气旋涡对于长鳍金枪鱼空间分布具有不同的影响机制。本研究进一步加深了对海洋中尺度涡与长鳍金枪鱼空间分布之间复杂关系的理解,为渔业捕捞效率的优化和可持续管理提供了科学依据。

关键词:长鳍金枪鱼;中尺度涡;EddyNet深度学习模型;单位捕捞努力量渔获量;南太平洋

Abstract:

In order to explore the modeling of the impact of mesoscale eddies on albacore tuna （Thunnus alalunga） catches in the South Pacific Ocean, and to reveal the correlation between different types of eddies and longline catches of albacore tuna in the South Pacific Ocean, in this study, the EddyNet deep learning model was used to automatically identify and detect mesoscale eddies in the South Pacific Ocean based on eddy feature environmental data, and combined with fishery sounding data to analyze the effects of the relative distances from the fishing stations to the eddy edges and eddy centers on the catch per unit effort （CPUE） of albacore tuna. The results show that anticyclonic eddies in the South Pacific Ocean are usually more numerous than cyclonic eddies and have a larger radius than cyclonic eddies. From beyond the eddy edge, both cyclonic and anticyclonic eddies showed a decreasing trend in CPUE for albacore tuna as the relative distance from the fishing site to the nearest eddy edge increased. Within the eddy disturbance region, the CPUE of the anticyclonic eddy was higher than that of the cyclonic eddy, and gradually decreased as the relative distance from the fishing site to the center of the eddy increased. The study suggests that the mesoscale has a positive regulatory effect on catch yield compared to the background field, and that the anticyclonic and cyclonic eddies have different influence mechanisms on the spatial distribution of albacore tuna. This study further deepens the understanding of the complex relationship between oceanic mesoscale eddies and the spatial distribution of albacore tuna, and provides a scientific basis for the optimization of fishing efficiency and sustainable management of fisheries.

Key words:Thunnus alalunga;mesoscale eddy;EddyNet deep learning model;CPUE;South Pacific Ocean