Excessive carbon emissions will cause irreversible damage to the human living environment. Therefore, carbon neutrality has become an inevitable choice for sustainable development. Marine fishery is an essential pathway for biological carbon sequestration. However, it is also a source of carbon emissions. From this perspective, an in-depth assessment of the performance of carbon emissions and sinks from marine fisheries is required to achieve the goal of carbon neutrality. This paper measured the carbon emissions, carbon sinks, and net carbon emissions of marine fisheries in nine coastal provinces of China from 2005 to 2020 for the first time. Based on the calculation results, the log-mean decomposition index method was used to analyze the driving factors of net carbon emissions. The results suggested that, from 2005 to 2020, both the carbon emissions and carbon sinks of China’s marine fisheries increased, and the net carbon emissions showed a downward trend. There were variations in the performance of carbon emissions, carbon sinks, and net carbon emissions in different provinces, and only Shandong could consistently achieve carbon neutrality. Fujian and Liaoning achieved carbon neutrality in 2020. In terms of the contribution of each factor, the industrial structure was the main positive driver, and carbon intensity was the main negative driver. Based on the empirical results, this paper suggested increasing the implementation of the carbon tax policy, establishing a farming compensation mechanism and promoting carbon emissions trading and international blue carbon trading. The results could give a reference for the energy conservation and emission reduction of marine fisheries while enhancing the ecological benefits of their carbon sinks and helping to achieve the carbon neutrality target.

Addressing the urban–rural income disparity and fostering coordinated urban–rural development pose critical challenges for China in pursuit of its common prosperity strategy during its new phase of development. Regional integration emerges as a pivotal policy tool, which is extensively utilized to facilitate regional development coordination and significantly contributing to overall regional economic growth. This study delves into whether the implementation of regional integration policies generates a common prosperity effect, thereby reducing the disparity in income levels between urban and rural regions. Utilizing city-level panel data spanning from 2000 to 2019 within the Yangtze River Delta region, we treat the expansion of regional integration as a quasi-natural experiment and employ a time-varying Difference-in-Differences model to identify the integration’s common prosperity effect. Furthermore, we leverage mediation effect models to unravel the mechanisms through which integration influences the urban–rural divide in income. Our findings reveal that the expansion of integrated regions contributes to narrowing the urban–rural income gap with these results remaining robust across multiple tests. Urbanization and marketization are pivotal mechanisms driving the reduction in the urban–rural income disparity in integrated regions. Additionally, heterogeneity analysis uncovers significant spatial and temporal variations in the urban–rural income gap narrowing effect of integration expansion. Specifically, over time, the effect transitions from a significant negative impact to an insignificant positive one, while spatially, significant negative effects are observed in Jiangsu and Zhejiang provinces, contrasting with insignificant positive effects in Anhui province. This study offers fresh perspectives on the nexus between regional integration and the urban–rural income disparity, laying a scientific groundwork to evaluate the impacts of urban agglomeration integration and optimize policies aimed at fostering regional integration and coordinated urban–rural development.