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 (Fig. 1A).
Hatchery release data in the ECS were obtained from Ningde Oceanic and
Fishery Bureau by adding the number of official L. croceahatchery release data in the Zhejiang and Fujian province (Fig .1A).
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.