Carbon budget and driving factors in marine fisheries in Liaoning Province, China

Marine fisheries are valuable oceanic carbon sinks that store and sequester carbon. They act as both “carbon sources” and “carbon sinks”, and this is particularly important to achieve the established carbon peak and carbon neutrality goals. The amount of carbon sequestered by fisheries and its economic value in Liaoning Province from 2006 to 2020 were calculated based on the China Fisheries Statistical Yearbook, the Calculation Reference of Oil Consumption for Oil Price Subsidy of Domestic Fishing Vessels, and the China Statistical Yearbook. Then, a cubic exponential smoothing method was applied to a time-series forecasting model to predict the same parameters for 2021–2030, and the factors controlling the amount and economic value of carbon sequestered in fisheries in Liaoning Province were examined using gray correlation analysis. The results showed that 1) the surplus of income and expenditure for carbon sequestration in marine fisheries in the region decreased each year from 2006 to 2020, and the deficit is predicted to intensify in 2021–2030. 2) The maximum surplus of carbon (sequestration minus emissions) was 256.36×10⁴ tons and the maximum deficit was 29.99×10⁴ tons, with an average of 116.66×10⁴ tons per year. 3) The total amount of carbon sequestered by shellfish and algae was 241.67×10⁴ tons, 83% of which was attributed to the aquaculture industry, with little change. 4) The average amount of carbon emissions form marine fishing was 164.52×10⁴ tons per year, almost 50% of which was attributed to trawling. The amount of carbon sequestered from marine fishing could not compensate for carbon emissions after 2017. 5) The total economic value of sequestered carbon of marine fisheries of Liaoning Province was 27.423 billion Yuan, with an annual average of 1.828 billion Yuan. 6) The total amount and economic value of carbon sequestered in marine fisheries continued to decline and were positively correlated. 7) The amount of sequestered carbon was also positively correlated with fishing yields, shellfish production, and macroalgal culture. The amount and economic value of carbon sequestered in marine fisheries in Liaoning Province were significantly influenced by national policies, fishing yield, number of employees, area of shellfish and macroalgal aquaculture sites, and the total power of fishing vessels (which determined the vessels’ carbon emissions). To protect marine biodiversity and promote the sustainable development of marine fisheries in the area, it is recommended to integrate multiple aquaculture systems, reduce high-energy-consuming fishing operations, and strengthen the monitoring of highly polluting fishing vessels.