Carbon Emission Efficiency, Technological Progress, and Fishery Scale Expansion: Evidence from Marine Fishery in China

China’s technical progress on emissions and vast ocean area make the study for CO2 emission reduction suitable in a marine fishery. This study uses the slack variables of SBM and the Malmquist index to analyze the CO2 emission efficiency of Trawler, Seine net, Drift net, Fixed net, and Angling, along with their efficiency values, distinguishing the impact of technological progress, scale expansion, and technological efficiency. Results show that the CO2 emission efficiency of the Angling and Seine industry is high with the development potential of the low-carbon fishery. Moreover, China’s technological progress is increasing, but the technical efficiency of CO2 emission reduction is declining. Lack of pure technical efficiency is the primary constraint of low-carbon capture fishery, making changes in efficiency show a downward trend. These results expand the research depth of the efficiency impact of technological progress and reveal that technological progress keeps increasing, but the CO2 emission reduction efficiency is decreasing. This indicates that emission reduction requires both technological growth and the technology’s capacity to reduce CO2 emissions efficiently.