Modeling the growth of red sea bream (Pagrus major) in cage culture: A comparative evaluation of nonlinear models

The economic success of marine aquaculture for commercially significant species like Pagrus major hinges on predictable production cycles and efficient management. However, the growth dynamics of P. major in net-cage culture conditions are complex, shaped by fluctuating environmental variables and intensive management inputs, making accurate prediction of its growth trajectory a persistent industry challenge. Therefore, developing a robust and reliable growth model is a critical necessity for the sustainable development of the P. major industry. To address this practical need, a one-year growth monitoring study was conducted. Three nonlinear growth models, Logistic, Gompertz, and Von Bertalanffy, were fitted to the body weight data. The goodness-of-fit of these models was evaluated based on statistics such as the coefficient of determination ( R ²), Akaike information criterion (AIC), and Bayesian information criterion (BIC). The results showed that among the three models, the Logistic model provided the best fit for the body weight of net-caged P. major ( R ² = 0.980, lowest AIC and BIC values). Based on this model, the predicted asymptotic body weight ( A ) was 370.7 g. The age at the inflection point ( T i ) was 11.6 months, with a corresponding body weight at the inflection point ( W i ) of 185.3 g, and the maximum monthly weight gain ( M g ) was 43.9 g. The growth of P. major followed a sigmoid curve and exhibited distinct phasic characteristics: a relatively slow initial growth, a subsequent rapid growth period, and a decelerated growth rate in the later stage. These growth phase transitions coincided temporally with the dynamic changes in water temperature and salinity. This study provides a scientific basis and a practical model for the precision management, determination of optimal harvest size and timing, and evaluation of the economic efficiency of P. major aquaculture. • A pioneering comparison of growth models for a key cage-cultured fish species. • The Logistic model best describes the body weight growth of cage-cultured Pagrus major . • Water temperature is the key driver of growth, while salinity limits the early stages.