Abstract
For successful economic management of cephalopod fisheries, short-lived squid with a 1-year life span require stock assessment over a short timescale, accompanied by both in-season and real-time stock management. However, insufficient information is available about the dynamic distribution patterns of the squid Uroteuthis duvauceli, Uroteuthis edulis, Loliolus sumatrensis, and Loliolus japonica in China. Such information is vital for establishing a sustainable fisheries management system. In this study, seasonal fishery-independent bottom-trawling surveys were performed from 2018 to 2019 in the southern Yellow and East China Seas to assess the seasonal changes in the distribution of these species. Most U. duvauceli occurred at sea bottom temperatures (SBTs) of 24.52-26.96 °C and sea bottom salinity (SBS) of 30.2-31.54‱ during the summer and at 20.02-22.75 °C and 33.46-34.22‱ during the autumn. Most U. edulis occurred at an SBT of 18.29-19.61 °C and SBS 34.78-35.08‱ during the spring, at 18.63-19.43 °C and 34.43-34.66‱ during the summer, at 8.78-21.81 °C and 34.39-34.77‱ during the autumn, and at 17.90-21.55 °C and 34.34-34.61‱ during the winter. Overall, most L. sumatrensis occurred at 21.00-23.15 °C and 34.11-34.50‱ in autumn. U. duvauceli concentrated in the fishing grounds of Zhoushan during the spring, Lvsi and Zhoushan-Changjiangkou during the summer, Zhoushan and Yushan-Mindong during the autumn, and Wentai-Yushan during the winter. L. sumatrensis mainly occurred in the fishing grounds of Dasha, Changjiangkou-Zhoushan, and Mindong during the summer, Yushan during the autumn, and nearshore areas during the winter. Most L. japonica occurred in the fishing grounds of Haizhou Bay and Zhoushan-Yushan during the spring, Haizhou Bay during the summer, Lvsi during the autumn, and Haizhou Bay during the winter. Our results will be useful for determining the total allowable catch from squid fisheries in these areas in China.