Spatial niche and differentiation of major nekton species in Yueqing Bay, Zhejiang, China

Abstract

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.