Research on the Synergistic Effect of the Composite System for High-Quality Development of the Marine Economy in China

The key to achieving the high-quality development of the marine economy (HDME) is to facilitate synergy through the coordination of marine elements. By adopting a perspective concerning complex systems, this paper presents a comprehensive framework—the composite system for high-quality development of the marine economy (CSHDME)—that synergistically integrates the five dimensions of “economy—technology—ecological—society—culture” in the marine domain. Building upon this framework, in this paper, we construct a CSHDME synergy evaluation index system using relevant data from 11 coastal provinces in China from 2010 to 2020. We utilize the subsystem orderliness degree model and composite system synergy degree model to calculate the degree of subsystem orderliness and degree of composite system synergy for the CSHDME as well as analyze the development status of the CSHDME subsystem and the degree of CSHDME synergy. The results indicate that: (1) the five-dimensional subsystem of the CSHDME exhibits an overall trend of year-on-year growth, with significant development disparities; (2) the degree of the synergy of the CSHDME is characterized by strong regional differences, strong fluctuations, instability, and low synergy; (3) the degree of the synergy of the CSHDME demonstrates the spatial evolution characteristics of low synergy, strong differences, strong fluctuations, and high agglomeration; and (4) the degree of orderliness and development speed of subsystems affect the degree of the synergy of the CSHDME. Therefore, measures such as the rational allocation of marine resources, accurate improvement of shortcomings, optimization of the spatial layout, and strengthening of regional cooperation should be considered to further promote the synergistic development of the CSHDME.