Seasonal Spatial Distribution Patterns of Abralia multihamata in the East China Sea Region: Predictions Under Various Climate Scenarios

The enoploteuthid squid species Abralia multihamata plays an important role in the epi- and mesopelagic food web. However, little is known about its seasonal and spatial distribution, life history traits, and environmental threats that may affect it. In this study, we used independent scientific bottom trawling surveys conducted in the southern Yellow and East China Seas during 2018-2019 to identify the seasonal spatial distribution characteristics of biomass, number, and size of this species as well as the relationships among these features and measured environmental factors. We also predicted the habitat distribution variations of the species under different climate scenarios (the present, SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) and seasons. The results revealed a continuously increasing individual size from the southern Yellow Sea to the East China Sea in spring, summer, and autumn, which suggests the possibility of growth differences in different water temperature conditions. The seasonal order of regional mean biomass and number was autumn > spring > summer and winter in the study area, and, for size, it was spring > summer and autumn > winter. This result shows that the majorities of recruitment and breeding groups occurred in autumn and spring, respectively. In addition, our results showed that the most beneficial case in terms of average habitat area was SSP3-7.0 in 2050, and the most loss occurred under SSP1-2.6 and SSP5-8.5 in 2100. Few benefits were predicted for the other cases under the various climate scenarios. This study provides a new understanding of the distribution and life history of A. multihamata in the East China Sea region.