渤黄海区域渔船碳排放特征

Carbon emissions from fishing vessels in the Bohai Sea and Yellow Sea

渔船二氧化碳排放是全球温室气体排放评估中通常被忽视的领域,对全球变暖过程具有不可忽略的驱动作用。渤黄海是中国重要的海上粮仓和生态环境治理区域,查明渤黄海渔船生产作业过程对温室气体排放贡献较大的环节,对区域碳循环研究、碳排放管理及减排降碳措施制定具有重要意义。为探明渤黄海区域海洋渔船二氧化碳排放的时空变化特征,揭示渔业生产活动对气候变暖的影响程度,该研究基于2020和2021年的海量渔船管理及动态船位数据,提取了航段位移、航段内渔船航速、发动机负荷因子、排放因子等状态参数,构建了渔船二氧化碳排放动态计算模型,分析了渤黄海区域9种作业类型渔船的二氧化碳排放强度,给出了渔船年度及月度排放的空间分布特征。结果表明:1)渤黄海区域各类机动渔船在2020和2021年的二氧化碳排放总量分别为450万和945万t,总体呈现出近岸低、外海高的分布特征,热点区域主要分布在渤海湾渔场、滦河口渔场、海东渔场、烟威渔场、石岛渔场、石东渔场、海州湾渔场及大沙渔场。2)拖网和刺网渔船是二氧化碳年度累计排放的主要贡献者,但就单船单位航行时长二氧化碳排放量而言,辅助船最高,围网渔船次之。3)不同年份相同月份的渔船二氧化碳排放空间分布呈现出一定的相似性,伏季休渔期开始前强碳源主要出现在黄海中南部区域,休渔期结束后强碳源主要出现渤海中部、山东半岛东部以及黄海中部海域一带,年度内渔船二氧化碳排放重心总体上是由沿岸海域向中部开阔海域方向扩散。该研究通过渔船动静态异质数据推演二氧化碳的时空变化,对评估渔业生产所引起的气候效应具有理论指导作用。

The Bohai Sea and the Yellow Sea have been the essential marine granary and eco-environmental governance areas in China. Wherein the carbon dioxide emission from fishing vessels can be normally neglected to assess the global greenhouse gas(GHG). It is very necessary to identify the specific contribution of the productive fishing vessels to the GHG emission, in order to reduce the carbon emission for the carbon neutral. Taking the Bohai Sea and the Yellow Sea as the research areas, this study aims to explore the spatiotemporal characteristics of carbon dioxide emission from the fishing vessels. A dynamic calculation model of carbon dioxide emission from fishing vessels was established using vessel management and position data,in order to reveal the impact of fishery production activities on climate warming. Nine types of fishing vessels were also selected to analyze the carbon dioxide emissions intensity and spatiotemporal characteristics from 2020 to 2021. Results showed that: 1) The total carbon dioxide emissions of fishing vessels in Bohai Sea and the Yellow Sea were 4.5 and 9.45million tons, respectively, indicating the distribution characteristics of low nearshore and high offshore. Hot spots were distributed mainly in the fishing ground of Bohai Bay, Luanhekou, Haidong, Yanwei, Shidao, Shidong, Haizhou Bay, and Daisha. Every ton of fishing catches emitted approximately 1.57 and 3.27 t of carbon dioxide, respectively, when considering the yield data. 2) Trawler and gillnet fishing vessels were the main contributors to the total carbon dioxide emissions,accounting for more than 70% of the total emissions from all fishing vessels. Among them, the auxiliary vessels were the highest, followed by the purse seiner vessels, in terms of emissions per vessel per unit sailing time. Carbon dioxide emissions per unit sailing time from the single vessel were similar to the trawler, gillnet, stow net, purse seine, auxiliary, and unknown types, whereas, there was the significant difference for the line, and aquaculture types. 3) There was the similar spatial distribution of carbon dioxide emissions from the fishing vessels in the same month in the different years. But the hot spots exhibited a strong spatial difference. Firstly, the hot spots occurred in the central and southern part of the Yellow Sea from January to April, where a high-value belt was extended the southeast from the Haizhou Bay to the East China Sea. Then, there was no carbon dioxide emission in the offshore area from May to August. Eventually, the hot spots were shifted to the central Bohai Sea, the eastern Shandong Peninsula, and the central Yellow Sea from September to December. In general, the center of gravity of carbon dioxide emission from the fishing vessels was transferred from the coastal to the central open waters. The finding can provide a theoretical basis for the transformation of fisheries into the low carbon. Two suggestions were also proposed to reduce the carbon emissions of fishing vessels. One is to accelerate the transformation of fishery production and product formats, and another is to strengthen the carbon emission management of key fishing vessels and key areas. In the end,it can be expected to assess the carbon emission system for the fishing vessels.