Changes in Seasonal Spatial Distribution Patterns of Euprymna berryi and Euprymna morsei: The Current and Predictions Under Climate Change Scenarios

Given their small size and low value in commercial fishing and aquaculture, little is known about the seasonal spatial distribution patterns and characteristics of the bobtail squid <i>Euprymna berryi</i> and <i>Euprymna morsei</i> in seas around China. Thus, we conducted seasonal bottom-trawling surveys in the southern Yellow and East China Seas during 2018 and 2019. Our results showed that <i>E. berryi</i> migrated from inshore areas (Yushan fishing grounds) during the summer and autumn to offshore areas (Wentai fishing grounds) during the winter. In contrast, <i>E. morsei</i> migrated from shallower water areas during the spring to deeper water areas during the winter. The highest abundance of <i>E. berryi</i> versus <i>E. morsei</i> was found in areas where temperatures were 25.29-28.02 °C compared with 19.54 °C (33.43-34.04‱ versus 34.43‱), respectively, during the summer; 20.99-21.69 °C compared with 21.98-22.70 °C (34.07-34.50‱ versus 33.80-33.60‱), respectively, during autumn; and 17.13-20.36 °C compared with 10.51-13.49 °C (34.23-34.46‱ versus 31.69-33.42‱), respectively, during winter. We predict that suitable habitats for <i>E. berryi</i> would expand more northward under SSP585-2050, whereas those for <i>E. morsei</i> would shrink into more northern locations under SSP370-2100 and SSP585-2100. The SSP245-2100 and SSP585-2100 scenarios had the most negative impacts on the distributions of both species. Such insights improve our understanding of the population dynamics and habitat requirements of both species to support their population management and exploitation in response to future climate change.