时空及环境因子对黄河口及邻近水域斑鰶资源丰度的影响

斑(鰶)(Konosirus punctatus)作为黄河口及邻近海域近年来的优势种,其在生态系统中的作用日趋重要,为研究其资源丰度的变动对生态系统中多种生物的影响,本研究根据2013年6月、8月、10月在黄河口及邻近海域进行的渔业资源和环境调查数据,利用广义可加模型(GAM)分析了该海域夏、秋季斑(鰶)资源丰度分布特征及其与时空和环境因子的关系.结果表明,黄河口及邻近海域斑(鰶)资源丰度呈现明显的季节变化,斑(鰶)资源丰度秋季较高,夏季较低;其主要分布在黄河入海口以北的近岸海域.GAM分析表明,月份、水深、海水表层盐度和浮游植物丰度对斑(鰶)资源丰度分布具有显著影响.斑(鰶)资源丰度随浮游植物丰度的增大而增大;在10m水深范围内随水深增加呈下降趋势;一定盐度范围内,斑(鰶)资源丰度随表层盐度的增加而增大,当盐度达到17时其丰度达到最大.因此,在浮游植物丰度较高的低盐河口水域,斑(鰶)资源丰度较大,这与斑(鰶)的洄游习性、河口区受到淡水径流和海水运动共同作用所形成的环境因子的变动有关.

Generalized additive model reveals effects of spatiotemporal and environmental factors on the relative abundance distribution of Konosirus punctatus in the Yellow River estuary and its adjacent waters

Konosirus punctatus is an important detritus-feeding fish and the prey of many high-trophic-level species in the Yellow River estuary ecosystem.Thus,K.punctatus has large effects on the abundance distribution of many fish species in the waters.The distribution of K.punctatus relative abundance in relation to spatiotemporal and environmental factors were analyzed using generalized additive models (GAM) based on bottom trawl surveys conducted during July,August,and October 2013 in the Yellow River estuary and its adjacent waters.Pearson correlation analysis was indispensable for determining whether factors introduced in the model were significantly correlated,as included variables should be independent.The relative abundance of K.punctatus varied noticeably with resource abundance,being high in autumn and low in summer.Additionally,K.punctatus was mainly distributed in the coastal waters of the northern Yellow River estuary;however,with seasonal decreases in food resources and temperature,the distribution gradually moved to the open sea.A minimum Akaike information criterion (AIC) was used to determine the best-fit.GAM,via a stepwise method.Month,depth,sea-surface salinity,and phytoplankton abundance significantly affected the abundance distribution of K.punctatus in the Yellow River estuary and its adjacent waters.The final model explained 56.96％ of the deviance,with phytoplankton abundance contributing the most (21.04％).Konosirus punctatus abundance generally decreased with depth and increased with increasing phytoplankton abundance and sea-surface salinity.Specifically,abundance was relatively high in phytoplankton-rich waters ＜10 m in depth and with a sea-surface salinity of 17.These conditions may be related to reproduction-related migration,as well as estuarine environmental variation from the combined effects of freshwater runoff and tidal movement.In a future study,more data on quantifiable social and biological factors will increase the reliability of our conclusions.Nonetheless,the results of this study should contribute to the conservation and sustainable use ofK.punctatus in the Yellow River estuary and adjacent waters.