is an important economic fish species from coastal China. It is also one of the few large-scale catch species that maintain a high yield in China. Studies have shown that the relationship between fork length and body weight differs between seasons and areas. To better understand the seasonal and sexual variations in relationships between the fork length and weight (, we used the trawl survey data at the East China Sea fishing grounds from October 2018 to March 2019 and constructed a generalized linear model and nine linear mixed models. Based on the collected 367 samples, the relationship between fork length and body weight () is obtained, in which the estimated mean value of condition factor a is 3.022×10^-5, and the estimated mean value of allometric growth parameter b is 2.794. Both the Bayesian Information Criterion (BIC) value and the root mean square error (RMSE) value indicated that the most complex linear mixed model (i.e. month and gender have random effects on both parameters ) had the best performance. According to the results of the difference analysis between the best model and the generalized linear model, the relationship between the fork length and weight of <0.01). In the best model, was higher in October and November (feeding period) and lower in December and January (overwintering period), while was higher in males and lower in females. It can be concluded that the relationship between the fork length and weight of was significantly affected by season and sex. The linear mixed model allows the easier combination of season and sex, which would be of great value in the heterogeneity studies of fish life history traits.