The coastal provinces differ in their level of economic development, geographic location, and climatic conditions. Therefore, they also show different locational characteristics in the development of marine fisheries. To further understand the spatial and temporal evolution of carbon emissions, carbon sinks, and net carbon emissions, the following analysis is carried out at the provincial level.
4.2.1. Provincial Characteristics of Carbon Emissions
Table 3 shows that, among the nine Chinese coastal provinces, only Guangdong and Guangxi showed a decreasing trend in overall carbon emissions. Carbon emissions increased in the remaining seven provinces, and the most significant increase was seen in Hainan. In 2005, Zhejiang had the largest carbon emissions, reaching 4.744 million tons. While this total was much higher than other provinces, Zhejiang’s growth and increment were better compared with other provinces. The province with the least carbon emissions was Hebei, which was also related to the smaller farming scale in Hebei. The increase in Hebei was relatively large, which indicates that Hebei’s marine fishery needs to increase the implementation of energy conservation and emission reduction. In 2020, the provinces with the most and least carbon emissions were still Zhejiang and Hebei, but the gap between the two had narrowed. The province with the largest increase in carbon emissions was Hainan. Although Hainan’s carbon emissions were not high among the nine provinces, they had almost doubled from 2005 to 2020. Therefore, the carbon emission reduction work of China’s marine fishery can be appropriately tilted to Zhejiang and Hainan.
Figure 2 can reflect the trend of carbon emissions in nine provinces during this period. Regionally, the northern provinces include Liaoning, Hebei, and Shandong; the eastern provinces include Jiangsu and Zhejiang; and the southern provinces include Fujian, Guangdong, Guangxi, and Hainan. Carbon emissions were increasing in both the northern and eastern provinces, with the southern provinces performing better than the other two regions.
Most of the provinces showed slight fluctuation, but the trend of fluctuation was obvious in Zhejiang and Hebei. Since 2005, Zhejiang has implemented the upgrading and technological transformation of its shipbuilding industry, erasing the former of its shipbuilding as “small, scattered and low”. However, the rapid development of Zhejiang’s shipbuilding enterprises also made its carbon emissions be firmly at the forefront of China. In 2007 and 2012, there was a significant increase in carbon emissions in Zhejiang. In 2011, the State Council of China approved the Zhejiang Marine Economic Development Demonstration Zone Plan, which elevated the construction of marine economic development demonstration zones to a national strategy. This plan has driven the expansion of factory farming areas in Zhejiang, leading to a rapid increase in carbon emissions. Aquaculture engineering and equipment integration support was not enough, and it restricted, to a certain extent, the implementation of carbon emission reduction in Zhejiang marine fisheries. In 2008, Hebei’s carbon emissions increased significantly. On the one hand, Hebei continued to promote factory farming, excellent breeding selection, and other technologies. On the other hand, Hebei’s investment in science and technology for marine fisheries was weak. These factors led to notable fluctuations in Hebei’s carbon emissions. During the 11th Five-Year Plan period, Hebei promoted the transformation of marine fishery development from a quantity–speed type to a quality–benefit type. As a result, Hebei’s carbon emissions reduced for a period, starting in 2008. Yet, the shortage of scientific and technical personnel and the outdated instrumentation of Hebei’s marine fisheries caused a high growth rate of its carbon emissions.
Guangdong’s carbon emissions were on a steady downward trend. As a major aquatic province in China, Guangdong’s factory farming area was expanding. Nevertheless, Guangdong’s carbon emissions decreased rather than increased, indicating the healthy development of Guangdong’s marine fisheries. Guangdong strictly controlled its fishing intensity, promoted high-yield and low-consumption operations, and vigorously developed “deep blue fisheries” to achieve resource conservation and environmental friendliness. In addition to Guangdong, the carbon emissions of Guangxi were also declining. Guangxi had only one significant increase in emissions in 2008. The power of motorized fishing vessels in Guangxi was high that year, and then it started to fall back. In recent years, the marine fishing system in Guangxi gradually became more established, and the structure of fishing vessel operations became more reasonable, so carbon emissions showed a decreasing trend. Guangxi actively established fishery science and technology innovation platforms and accelerated the technical research and promotion application of marine fishery. Guangxi has a wealth of marine fisheries resources but they are currently underutilized and have great potential for development. When vigorously developing these fishery resources, Guangxi needs a good resource and ecological monitoring system to ensure the smooth development of the fishery.
The carbon emissions of Fujian and Hainan had been growing steadily. Fujian started to build the modern marine industry development base in 2009, which provided an opportunity to develop its marine fishery. Fujian has abundant water resources and a relatively complete fishery infrastructure in terms of fishery development. However, in developing marine fisheries, Fujian should pay attention to industrial structure optimization and expand its advantages. Hainan has been continuously optimizing the internal structure of fisheries and accelerating infrastructure construction in recent years. However, due to insufficient investment in fishery science and technology and a lack of talents, there was still a big gap between the development of its fishery and the more advanced provinces. Consequently, Hainan needs to increase investment in scientific research, strengthen the support force of science and technology, and control carbon emissions while developing marine fisheries.
The carbon emissions of Liaoning, Jiangsu, and Shandong were also fluctuating, but the fluctuation was not as noticeable. These provinces all attached great importance to the development of marine fisheries but were still searching for a development model suitable for themselves. During the 13th Five-Year Plan period, Liaoning issued the “Guiding Opinions on the Development of Fishery Industry in Liaoning Province”, highlighting that Liaoning needs to speed up the transformation of the fishery development model. In this period, Liaoning has increased scientific investment in areas such as marine engineering equipment and energy, and it has carried out essential technology research. New fishery species, marine robots, and other marine science and technology achievements have emerged one after another. As a result, there was a period of decline in Liaoning’s carbon emissions from 2016 onwards. Liaoning has a good foundation of marine resources and is actively developing ecologically healthy aquaculture and sustainable fishing. However, while developing marine fisheries, Liaoning needs to speed up the construction of fishery infrastructure and reduce the pollution of carbon emissions to the environment. As an important part of the Yangtze River Delta region, Jiangsu has convenient logistics channels for developing marine fisheries. Jiangsu released a special action plan for marine fisheries in 2017 stating the aim of reducing the environmental impact of fisheries production. Jiangsu launched a fishing boat renovation program. Jiangsu eliminated old fishing boats, renovated several energy-consuming and inefficient fishing boats, updated a group of high-quality marine fishing boats, and completed the establishment of safety equipment for fishing boats. Consequently, carbon emissions in Jiangsu declined from 2017 onwards. Since the implementation of the marine fishing vessel renewal project in 2012, Shandong has improved the quantity and quality of fishing vessels through construction and renovation. As a result, there was a marked increase in carbon emissions in Shandong. In 2016, Shandong introduced the policy of oil price subsidy for fisheries fishing and aquaculture. This policy guided the fishing fishermen to reduce the number of vessels and to switch to production and ecological restoration, so that the number and power of fishing vessels were further reduced and fishing intensity was effectively controlled. The carbon emissions of Shandong’s marine fisheries have also been gradually reduced since 2016.
It can be noted that the fishery development gap between the provinces was gradually decreasing. Different provinces should rely on their resource endowments to seize the opportunity for marine fisheries development. While developing marine fisheries, provinces need to pay attention to the green and low-carbon concepts, form a stable development space, and reduce the environmental pressure on the ocean.
4.2.2. Provincial Characteristics of Carbon Sinks
As shown in
Table 4, only the overall carbon sink of Hainan was on a decreasing trend. The remaining eight provinces saw an increase in carbon sinks, and Hebei had the most significant increase. In 2005, Shandong’s carbon sink was the largest, reaching 2.247 million tons. Hainan had the lowest carbon sink at 0.047 million tons, and its sink was still declining. In 2020, Fujian surpassed Shandong as the largest carbon sink, reaching 3.506 million tons. Hainan still had the lowest carbon sink, with only 0.018 million tons. The gap in carbon sinks between the coastal provinces was growing. The province with the largest increase in carbon sinks was Hebei, which almost doubled its carbon sinks in 2020 compared to 2005. In terms of both the number and the growth rate of carbon sinks, Hainan was lagging. Therefore, the shellfish and algae aquaculture in China’s marine fisheries requires increased efforts to promote Hainan.
Figure 3 reflects the changing trend of carbon sinks in nine coastal provinces from 2005 to 2020. The carbon sinks in the northern provinces of Hebei, Liaoning, and Shandong fluctuated and eventually showed an upward trend. The carbon sink values of Jiangsu and Zhejiang in the eastern provinces were not as good as those of other regions but were on the rise as a whole. Fujian has an abundant and steadily increasing carbon sink among the southern provinces.
The fluctuation trends of Hebei, Liaoning, and Hainan were evident. Shellfish farming is a significant pillar of Hebei’s fishing industry. Due to the rapid expansion of shellfish and algae farming in the northern marine economic circle during the 12th Five-Year Plan period, Hebei’s carbon sink increased steadily from 2011 to 2015. The expansion of the farming scale had led to high farming density in local areas of Hebei, approaching the upper limit of the carrying capacity of the marine environment. The environmental degradation of the sea area threatened the sustainable development of Hebei’s marine fisheries, and, as a result, Hebei’s carbon sink began to decline significantly in 2016. Liaoning published and implemented the Liaoning Modern Sea Ranch Construction Plan in 2011. Focusing on the goal of marine pasture construction, Liaoning carried out actions such as resource restoration and sea farming to guarantee the development of its farming scale. However, the environmental degradation of the northern marine economic zone had also affected shellfish and algae farming in Liaoning, leading to fluctuations in its carbon sink. Hainan’s marine economy has been focused on developing coastal tourism. With the construction of an international tourism island in Hainan, the land for fishing in Hainan was gradually reduced and the space for fishing development was squeezed. At the same time, the development of the Hainan farming industry accelerated the eutrophication of coastal waters, which negatively affected the ecological environment of coastal waters and restricted the sustainable development of the farming industry. As a result, the carbon sink of Hainan started to decline sharply in 2017, which eventually resulted in the carbon sink decreasing instead of rising.
The overall upward trend in Zhejiang, Fujian, Shandong, and Guangxi was relatively stable. As a pilot province for the development of China’s marine economy, the farming industry in Zhejiang has more development opportunities. In the 13th Five-Year Plan for marine ecological protection in Zhejiang Province, the government emphasized the need to actively develop shallow sea shellfish and algae ecological health culture models. Zhejiang implemented the shallow marine aquaculture space expansion project, guided the seawater pond recirculating water aquaculture and industrial recirculating water aquaculture, and developed offshore intelligent deep-water nets, large seine nets, and block nets. Consequently, between 2016 and 2020, the carbon sink in Zhejiang achieved rapid growth. With the development of port-side industries and accelerated urbanization in coastal areas, Fujian’s marine fisheries were gradually withdrawn from some traditional production areas. The fishery showed a trend of gradually increasing aquaculture output and decreasing fishing output yearly. To achieve sustainable growth of carbon sinks, Fujian should strengthen the construction of aquaculture facilities. Shandong has a vast ocean space and huge development potential. In recent years, the mariculture structure of Shandong was gradually optimized and production was steadily increased. However, in 2019 Shandong’s carbon sink had a fallback. Shandong can further improve the fisheries standards system and enhance the quality and safety of its aquaculture products. In the 11th Five-Year Plan period, Guangxi’s farming patterns were outdated, and the application of new farming patterns was not promoted much. Thus, Guangxi’s carbon sink declined in 2007. Guangxi is rich in fish farming resources, and its fishery economy’s structure and industrial layout are gradually being optimized. Guangxi established the monitoring system of the fishery ecological environment and increased the efforts of artificial breeding and releasing. As a result, the carbon sinks in Guangxi have increased steadily since 2008.
Jiangsu and Guangdong were the two provinces with insignificant fluctuation trends. Jiangsu built marine pastures offshore, created seaweed farms, and restored marine ecology, increasing the productivity of the sea. It can be seen that from 2006 to 2012, the carbon sinks in Jiangsu were steadily enhanced. However, the accelerated urbanization of Jiangsu has squeezed the development of fisheries, and the trend of increased pollution of waters and the decline of natural resources has not been fundamentally resolved. Jiangsu requires continuous strengthening of its marine living resources conservation efforts. Guangdong’s mariculture was at the leading position in China. Guangdong has taken “deep blue fisheries” as the focus of optimizing the structure of the fisheries industry. Moreover, Guangdong has established a “marine industrial zone” focusing on deep-water net tank farming. However, the performance of Guangdong’s carbon sinks was unstable and did not achieve a steady rise. In recent years, storm surges and red tide disasters have occurred in the coastal areas of Guangdong, and the government should focus on optimizing the resource environment of Guangdong’s fisheries.
It can be observed that the gap between the carbon sinks of each province was gradually widening. For provinces with more carbon sinks but unstable growth, the government should focus on marine environmental protection and promote the sustainable development of shellfish and algae farming. In provinces with low carbon sinks, the government can increase shellfish and algae farming to form more carbon sinks and neutralize the emitted carbon.