山东南部近海口虾蛄空间分布特征及其季节变化

为研究山东南部近海口虾蛄分布特征及其影响因素,根据2016年10月,2017年1月、5月、8月在该海域进行的底拖网调查,利用Moran’s I指数和分布重心法等分析方法,比较分析了2016—2017年4个季节口虾蛄空间分布特征及空间自相关性。结果发现,山东南部近海口虾蛄相对生物量各季节间差异明显,由高至低依次为夏季春季秋季冬季,其中口虾蛄春季相对生物量为0.75 kg/h,夏季相对生物量为3.02 kg/h,秋季相对生物量为0.65 kg/h,冬季相对生物量为0.22 kg/h。口虾蛄分布重心表现出明显的季节特征,春、夏季分布重心位于水深20～30 m,秋、冬季分布重心位于30～50 m。口虾蛄的分布在各季节均呈现显著空间正相关,Moran’ I指数由高至低依次为秋季(0.34)春季(0.30)夏季(0.28)冬季(0.16)。研究表明,不同季节口虾蛄分布重心的变化可能与其繁殖习性等生活史特征有关,而分布的空间聚集性可能与口虾蛄偏好淤泥质粉砂和砂-粉砂-黏土的底质环境相关。

Spatial distribution characteristics and seasonal variation of Oratosquilla oratoria in the southern coastal waters of Shandong Province

The present study analyzed the spatial distribution of Oratosquilla oratoria in the southern coastal waters of Shandong Peninsula based on bottom-trawl surveys in October 2016, January 2017, May 2017 and August 2017. We used center of gravity and Moran''s I index to estimate the distribution center of this species, compared the seasonal differences of spatial autocorrelation, and explored the potential influential factors of the spatial patterns. This study found substantial seasonal variations in the relative biomass of O. oratoria, which showed the highest relative biomass of 3.02 kg/h in summer, followed by 0.75 kg/h in spring, 0.65 kg/h in autumn and 0.22 kg/h in winter. The center of gravity showed remarkable seasonal changes, with the corresponding water depth ranging from 20 m to 30 m in spring and summer and from 30 m to 50 m in autumn and winter. The distributional pattern of O. oratoria was relatively consistent, exhibiting significantly positive spatial autocorrelation in four seasons. Moran'' I index was the highest in autumn (0.34), followed by spring (0.30) and summer (0.28), and was the lowest in winter (0.16). According to Moran'' I scatterplots, we identified survey sites with strong influence on biomass concentration. The seasonal changes in spatial distribution of O. oratoria might attribute to its spawning activities, and the biomass concentration implied that muddy silt and sand-silt-clay were the preference of sediment types of O. oratoria. We discussed the implications of our results for the management of O. oratoria and put forward the priorities for future fisheries research on spatial analyses.