Spatio-temporal distribution pattern and scale of density distribution for Antarctic krill (Euphausia superba) in the Antarctic Peninsula

Distribution pattern of living resources depends on the spatial scale, and inappropriate scales may lead to misleading results. As a key species in the Antarctic ecosystem, Antarctic krill (Euphausia superba) distribution demonstrates significant spatial-temporal heterogeneity. Therefore, the distribution pattern of this species cannot be predicted effectively. In order to understand the spatial-temporal distribution pattern of E. superba resources at different spatial scales, this study preprocessed scientific survey data into 12 spatial scales (5′×5′ - 60′×60′) at 5′ intervals of latitude and longitude and carried out multi-scale analysis of this species in the Antarctic Peninsula, which is the main distributional region of E. superba resources. And the Moran's I index of E. superba density distribution at different spatial scales was also calculated. The results showed that the spatial patterns of E. superba differed in spatial scales. The density distribution of resources showed a clustering trend at 11 spatial scales. According to the correlogram between Moran's I index and spatial scale, the characteristic spatial scales of E. superba density distribution were determined as 25′× 25′, which was determined by the Moran's I index crossing the point y=0 for the first time, and 15′× 15′, which was determined by the smallest scale with no significant difference between Moran's I index and zero, respectively. This study showed that the method with no significant difference between Moran's I index and zero value was more consistent with the characteristics of E. superba resources. It was, therefore, suggested that 15′× 15′ could be the optimum spatial scale for studying the distribution of E. superba density in this region.