New-Quality Marine Productive Forces and High-Quality Development of the Marine Economy in China: Mediating Mechanisms and Threshold Effect

With the implementation of China’s strategy to build a maritime power, new-quality marine productive forces have emerged as an important driver of high-quality development in the marine economy. Based on panel data from 11 coastal provinces in China covering the period 2013–2022, this study constructs a comprehensive evaluation index system for both new-quality marine productive forces and the high-quality development of the marine economy. It employs the entropy method to calculate a composite development index and uses panel models, mediation effect models, and threshold regression models to examine the mechanism through which new-quality marine productive forces influence the high-quality development of the marine economy. The study finds the following: (1) New-quality marine productive forces are positively associated with the high-quality development of the marine economy. (2) They are also positively associated with marine science and technology innovation, which in turn is associated with the high-quality development of the marine economy, suggesting a partial mediating role. (3) The level of economic development plays a nonlinear moderating role: the positive association is not significant at lower levels of economic development, strengthens at moderate levels, and weakens at higher levels.