A Spatio-Temporal Changes And Driving Factors Of Global Fishing From 2017 To 2020

Since ancient times,fishing has been an integral part of the development of human society.Fish have been an important part not only to the economy to the world,but also to the economy and well-being of communities.The capture and cultivation of aquatic life in seawater accounts for the majority of fishery products in the world market.The use of big data to monitor and manage fishing activities has become the mainstream of modern society.Therefore,this paper based on remote sensing data analyzes the spatio-temporal changes and driving forces of global fishing since 2017.Firstly,based on VIIRS DNB nighttime light data,global fishery observation data and water depth data,a prediction model of China’s offshore fishing activities was established to forecast the fishing activities of the South China Sea and its neighboring countries in 2017-2020.Secondly,combined with the forecast results and global fishery observation data,the temporal and spatial variation of global fishing activities was analyzed,and the temporal and spatial variation characteristics of global fishing gear were analyzed by using the global fishery observation data.Finally,the driving factors(culture,policy,season,and distance from port)of global fishing activities in 2017-2020 are quantitatively analyzed,and the impacts of COVID-19 on nearshore fishing activities in China,Spain,Japan,and the United States are analyzed.The main conclusions are as follows:(1)The constructed fishery fishing activity prediction model can make up for the shortage of global fishery observation data in the South China Sea and other regions.This paper combines the actual data to verify the accuracy of the predicted data.Data fitting R~2 is 0.72,with ρ equals to 0.89,indicating that the prediction accuracy is high and feasible,and the prediction results show seasonal characteristics.The high-intensity fishing range from 2017 to 2019 is distributed in the offshore and southern waters of Vietnam in the Gulf of Tonkin,and part of the offshore of the Gulf of Thailand,and the fishing range was relatively stable during spring and autumn.In 2020,the impact of COVID-19 reduced the seasons other than spring in the offshore areas of the South China Sea and its surrounding countries.(2)From 2017 to 2020,the global high-intensity fishing effort was mainly concentrated in the offshore of European countries,the offshore of China,the southern waters of Argentina and some waters of the Pacific Ocean.The fishing effort in other waters was less than 50,and the annual and monthly changes showed cyclical characteristics.In 2020,the fishing effort decreased by 5.2% compared with 2019.The global fishing gear was dominated by bottom trawling and longline fishing.Bottom trawling was mainly distributed in high and low latitude offshore,and longline fishing was mainly distributed in mid-latitude Pacific.In 2020,bottom trawler was the main reason for the decline of fishing gear,and longline fishing and other fishing gear had increased.(3)From 2017 to 2019,the quantitative impact of culture and policy on fishing effort was 5.76% and 12.83%,respectively.Therefore,policy had a greater impact on global fishing effort than culture.The global seasonal distribution is Autumn > Spring > Summer > Winter.The seasonal fishing effort increased about 10.54% on average from 2017 to 2019.Compared with 2019,the seasonal fishing effort declined 6.35% on average in 2020.The fishing activities mainly distributed in the area within 30 nautical miles from the ports.The average fishing effort from 30 to 200 nautical miles accounted for about 0.0625% of the total fishing effort.Affected by the COVID-19 policies,the month-on-month growth in four countries in January 2020 showed negative growth.Except for the United States,other countries’ fishing efforts all decreased compared to the previous three years,showing that the no blockade states of the United States were still conducting normal fishing activities.Compared to the first three years,the decline of fishing gear for the four countries was largely due to the use of trawler.