摘要
探索渔业资源丰度与环境因子的关系,并掌握种群分布对环境变化的响应机制,是养护资源、实现渔业可持续发展的基础.然而,渔业资源的变化受多个环境因素的综合影响,这些因素之间存在复杂且相关的关系.目前的研究主要集中于环境因子对种群分布和资源丰度等直接影响,而忽视了环境因素之间的相互作用.为了探索不同环境因子及其相互关系对毛里塔尼亚双拖鲣种群资源量的影响机制与路径,本研究基于2017-2019年毛里塔尼亚海域双拖渔业鲣(Katsuwonus pelamis)单位捕捞努力量渔获量(CPUE),采用结构方程模型(SEM)构建海表面温度(SST)、海表面盐度(SSS)、海面高度异常(SLA)、溶解氧(DO)和叶绿素a浓度(Chl-a)5个环境因子对鲣CPUE直接和间接影响.结果表明:SEM模型具有良好的拟合效果;SST、SSS、SLA、DO和Chl-a对鲣CPUE均有直接影响,其中DO和SLA对CPUE有着显著正相关影响,而SST、SSS和Chl-a对CPUE有显著负相关影响;SST等环境因子还会通过多种路径对鲣CPUE产生间接影响.研究揭示了毛塔海域SST通过直接影响或通过影响其他环境因子而间接影响鲣种群资源变动的潜在机制.
Abstract
Understanding the intricate relationship between fishery resource abundance and environmental factors is paramount for achieving sustainable fishery development and conservation goals.While previous studies have predominantly focused on the direct impacts of environmental factors on stock distribution and resource abundance,the underlying mechanisms remain poorly understood.To address this gap,we investigated the mechanisms through which various environmental factors and their interactions influence the abundance of skipjack tuna populations in Mauritanian waters.Utilizing catch per unit effort(CPUE)data spanning from 2017 to 2019,we employed structural equation modeling(SEM)to construct a comprehensive model assessing the direct and indirect influences of key environmental variables,including sea surface temperature(SST),sea surface salinity(SSS),sea level anomalies(SLA),dissolved oxygen(DO),and chlorophyll-a concentration(Chl-a),on skipjack tuna CPUE.Our findings demonstrate a well-fitting SEM model,revealing direct effects of SST,SSS,SLA,DO,and Chl-a on skipjack tuna CPUE.Notably,DO and SLA exhibited significant positive correlations with CPUE,while SST,SSS,and Chl-a displayed significant negative correlations.Furthermore,environmental factors such as SST exerted indirect effects on skipjack tuna CPUE through multiple pathways,shedding light on the potential impact mechanisms of SST and other environmental variables on skipjack tuna populations in Mauritanian waters.
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