The index of relative importance (IRI), niche breadth, and niche overlap (Qik) of nekton species were calculated using data collected from four fishery resource surveys from May 2016 to February 2017 in Yueqing Bay, Zhejiang Province. The results showed that there were 27 major nekton species (IRI＞100) with higher turnover rates across different seasons, while their niche breadth values differed greatly and showed significant positive correlation with IRI. The niche overlaps of nekton were generally low, with the highest overlap value in autumn and the lowest in spring. The total amount of species pairs with niche overlap over 0.6 (Qik＞0.6) were 14 in the autumn and five in the spring, which represented 15.4% and 7.6% of the total pairs, respectively. Results from the redundancy analysis suggested that the distribution of main nekton species were mainly affected by temperature, salinity and turbidity, which cause ecological differentiation of nekton species.
基于2016年5月至2017年2月在乐清湾进行的4个航次渔业资源调查数据,计算乐清湾主要游泳动物的相对重要性指数(IRI)、生态位宽度及生态位重叠值(Qik).结果表明:乐清湾全年主要游泳动物(IRI＞100)共27种,季节间更替率较高,生态位宽度值差异较大,相对重要性指数与生态位宽度值呈极显著正相关.全年游泳动物的生态位重叠值总体较低,秋季生态位重叠值最高,Qik＞0.6的种对有14对,占总种对数的15.4%;春季最低,Qik＞0.6的种对有5对,占总种对数的7.6%.冗余分析表明,温度、盐度和浑浊度是影响乐清湾主要游泳动物分布的重要因素,主要游泳动物在这些环境因子上存在生态分化现象.
Keywords: Yueqing Bay; niche breadth; niche overlap; redundancy analysis.