The high-quality development of the fishery economy (HQDF) is crucial to ensuring the sustainable supply of aquatic products. This study first conducts a theoretical analysis of the potential impacts of the digital economy (DE) on the HQDF and explores the underlying mechanisms. By using provincial panel data of China from 2011 to 2022, comprehensive indicator systems are constructed to measure the development levels of the DE and the HQDF. A two-way fixed effects model is employed to empirically examine the impact of the DE on the HQDF, with a focus on the mediating roles of technological innovation and entrepreneurial activity. The findings reveal that the DE significantly and positively drives the fishery economy towards high-quality development, and these results remain robust across various robustness tests and endogeneity treatments. Additionally, the transmission mechanisms of technological innovation and entrepreneurial activity enhancement are empirically validated. The impact of the digital economy exhibits regional heterogeneity. This study provides a scientific basis for achieving high-quality and sustainable development in the fishery sector, suggesting that fostering the digital economy, technological innovation, and entrepreneurship should be prioritized in policy interventions.

Under carbon emission reduction constraints, accurately assessing the spatial–temporal patterns and drivers of mariculture carbon emissions and sinks is critical for promoting marine economic development and achieving carbon neutrality. This study reviews key components of China’s mariculture carbon and analyzes provincial data from 2008 to 2023 using econometric models to estimate emissions, sinks, and net carbon values. Spatial heterogeneity and spillover effects are examined through geographically weighted regression, Moran’s I, and spatial Durbin models. The findings indicate the following: (1) Both direct and indirect mariculture carbon emissions are rising, with indirect emissions growing faster, notably in Shandong, Fujian, and Guangdong. (2) Shellfish carbon sinks generally dominate; algal carbon sinks are growing rapidly, especially in Fujian, Zhejiang and Shandong. (3) Net carbon values vary by region—positive in Liaoning, Hebei, Shandong, and Hainan, and negative in Jiangsu, Zhejiang, Fujian, Guangdong, and Guangxi. (4) Energy intensity increases emissions; industrial upgrading reduces them. Technological innovation, energy intensity, and ecological constraints enhance sinks. (5) Emission spillovers are positive for energy and negative for structure; sink spillovers are positive for energy and negative for technology; ecological effects are insignificant. Overall, shellfish and algae mariculture play a key role in China’s marine carbon sequestration. Regionalized carbon governance is essential to balance emissions–sinks, and to advance low-carbon mariculture.