基于GAM模型的东海中南部大黄鱼资源密度分布及其与环境因子的关系

Relationship Between Spatial-Temporal Distribution of Larimichthys crocea with Environment Factors in South Central East China Sea Based on Generalized Additive Model

为探究大黄鱼(Larimichthys crocea)资源密度与海洋环境因子之间的关系,本文基于2018年秋季和2019年春季东海中南部两个航次渔业资源调查数据,采用广义加性模型(Generalized additive model,GAM)对大黄鱼资源密度及其与环境因子的关系进行了研究。研究表明,大黄鱼尾数密度和生物量密度秋季为106.2 ind/km^(2)和6.57 kg/km^(2),春季为7.9 ind/km^(2)和0.45 kg/km^(2)。春季大黄鱼分布重心位于鱼山渔场,秋季分布重心南移进入温台渔场。广义加性模型分析结果表明:春秋两季最优模型均由离岸距离、温度、盐度组成,其中秋季最优模型的温度和盐度因子均为底层水体,而春季环境因子均为表层水体;春秋两季大黄鱼生物量密度均随温度上升而下降;秋季随着底层盐度的增加先上升后下降,最适底层盐度为33.7;春季随表层盐度升高而呈单调增加趋势。春季和秋季大黄鱼分布受到了不同水层环境的影响,这是由其栖息和繁殖特性的季节变动所导致的。本研究结果阐明了春秋季东海中南部大黄鱼资源分布情况及其对海洋环境因子的响应。

Larimichthys crocea is an important marine economic fish species in China,and its wild resources are declining and difficult to be restored.Understanding the relationship between the spatial-temporal distribution of L.crocea and marine environment factors should aid to providing an important basis for its resource protection and scientific restoration.In this study,based on the near-bottom trawling survey and environment observation data collected in the south-central East China Sea in autumn 2018 and spring 2019,using generalized additive model(GAM),we investigated the temporal and spatial distribution of L.crocea resources and the surrounding environmental factors of the sea area.The results showed that the resource and biomass density of L.crocea were 106.2 ind/km^(2) and 6.57 kg/km^(2) in Nov.,2018 and 7.9 ind/km^(2) and 0.45 kg/km^(2) in Apr.,2019,respectively.In spring,the distribution center of L.crocea located in Yushan Fishing Ground,and in autumn,the distribution center of L.crocea moved south to Wentai Fishing Ground.GAM model fitting results showed that the optimal model in both spring and autumn consists of offshore distance,temperature,and salinity.In autumn,temperature and salinity are associated with the bottom water,while in spring,environmental factors are associated with the surface water.In both seasons,the biomass resource density of L.crocea showed a monotonic decreasing trend with the increase of temperature.The biomass resource density increased and then decreased with the increase of bottom salinity in autumn,and the optimum bottom salinity was 33.7.Biomass resource density showed a monotonic increasing trend with the increase of surface salinity in spring.The distribution of L.crocea in different seasons was influenced by the environment of different water layers,which was caused by the seasonal change of its habitat and reproduction characteristics.The results of this study clarified the current status of the East China Sea L.crocea resource and the distribution of environmental factors along its migratory rout.