2.1 Fishery data
To investigate how L. crocea population declines in the ECS in the last five decades, we analyzed two data sets on L. crocea in the ECS.
First, we used information from official commercial landing and hatchery release data. Catch data of L. crocea were collected from theChina Fishery Statistical Yearbook . Annual catches during the year 1950 – 2019 in the ECS were calculated by adding the catch landing in the Jiangsu, Shanghai, Zhejiang and Fujian province. Hatchery release data in the ECS were obtained from Ningde Oceanic and Fishery Bureau by adding the number of official L. crocea hatchery release data in the Zhejiang and Fujian province.
Second, to investigate how geographical distribution of L. croceashifts in the ECS, we analyzed a second data set includes both commercial fishery and scientific cruise data in the L. crocea ’s overwintering ground (Fig. 1B). Historical overwintering catches information (1970 – 1982) of L. crocea was obtained from the East China Sea Fisheries Research Institute. The data set contains location and date, as well as the amount (in tons) of annual winter total catch (with 0.5° spatial resolution). Overwintering catch information and life-history parameters (including length and maturation) for L. crocea were obtained from scientific cruise data in the period 2018 – 2019 through a bottom trawl survey in the mid-southern ECS.