Impact of marine ranching demonstration areas on regional ecological efficiency - Trial evidence based on the SCM

The establishment of marine ranching demonstration areas is crucial for restoring offshore fishery resources, fostering ecosystem harmony, and creating blue "carbon sinks" in China. While their ecological benefits are evident, their impact on surrounding areas remains uncertain. This study takes the first batch of national marine ranching demonstration areas established in 2015 as a quasi-natural experiment and uses synthetic control methods to empirically evaluate the effects and mechanisms of their construction on regional ecological efficiency. Results show heterogeneous impacts, with positive effects in Jiangsu and Liaoning but negligible elsewhere. Mechanism analysis reveals that marine ranching demonstration areas enhance ecological efficiency through economic growth, and industrial structure optimization. Differences in marine ranching types and regulations influence their impact, with public welfare-oriented marine ranching showing greater positive effects compared to aquaculture-oriented ones. Overall, these findings hold theoretical and practical implications for advancing modern marine ranching construction.