Spatial Characteristics Mining Of Fishing Intensity In The Northern South China Sea In 2018 Based On Multi-Source Ship Position Data

High-precision fishing intensity data is the prerequisite and key to the development of fishing quota management,and it is also an important guarantee for the sustainable development of marine fishery resources.The development of big data,data mining and analysis,and remote sensing earth observation technology provides abundant data sources and technical support for the acquisition of marine fishery fishing intensity data.Accurate,in-depth analysis and visualization of the fishing space of fishing vessels is an important way to master the fishing intensity of fishery resources.Therefore,this article uses multi-source ship position data and takes the northern part of the South China Sea as the research area to excavate and analyze the2018 inter-monthly scale fishery fishing intensity data,in order to provide assistance and decision-making for the development of fishery resources in the South China Sea and the maintenance of marine fishery rights.The research contents include:(1)Based on the big data of the trajectory of the fishing boat AIS(Automatic Identification System),the fishing intensity data of the Chinese fishing boats in the northern South China Sea(Chinese waters)were obtained: combined with Natale et al.[24] existing research cases and expert knowledge in Sweden Experience,statistical characteristics of fishing vessel speed and examples of typical fishing vessel operations.A universal fishery fishing intensity analysis method is applied: fishing intensity is indirectly measured by the density of the track points generated by fishing boats at sea,and the fishing intensity is quantified by the level of the point density grid value.Analyze and dig out the spatial characteristics of fishery resources in the study area,and compare and analyze the fishing intensity obtained by using VBD(VIIRS Boat Detection)data;(2)For previous studies,focus on the use of single data sources such as AIS and VBD To obtain fishing intensity information,there are many practical problems such as limited data signal coverage of ships,discontinuous signal transmission,strong human interference,and VBD can only reflect light trapping fishing boats.From the perspective of adjacent matching and fusion of vector point data of two types of ship position: AIS with high temporal and spatial granularity,high revisit period and high sensitivity VBD,this paper constructs a framework of thinking for obtaining marine fishery fishing intensity information from fishing vessel data from two different sources.With the help of this method framework,an exploratory analysis and mining of the spatial characteristics and laws of the monthly fisheries fishing intensity in the northern part of the South China Sea(including part of the Vietnamese waters)in 2018 were carried out systematically.Research content(1)The results show that:(1)The high-intensity fishing information obtained based on AIS has a good effect in reflecting the fishing intensity within a range of about 50-70 km near the coast.The main reason is that the proportion of small and mediumsized fishing boats is 50.9.%,especially the coastal areas of Guangdong and Guangxi are rich in fishery resources;(2)Affected by the Spring Festival holiday and the summer ban/closed fishing policy in the South my country Sea,the fishing intensity during the banned/closed fishing period is significantly weaker than that of other months,with high intensity The fishing area mainly presents the forms of "clumps","stripes" and "clumps expanding and converging into strips".On the whole,the coastal fishing intensity of Guangdong and Guangxi is higher than that around Hainan Island;(3)Obtaining fishing intensity maps based on VBD is more objective in reflecting the spatial distribution of marine fisheries.Except for some highintensity fishing areas that overlap with the AIS data map,the high-intensity fishing areas are closer to the China-Vietnam Beibu Gulf maritime boundary and near the common fishing area.Therefore,effective integration of the two is a more comprehensive and accurate way to obtain fishing intensity information.Research content(2)The results show that:(1)166,858 AIS point targets covering the study area in 2018 obtained by trajectory interpolation,and 175,016 VBD ship position data obtained by screening are used for proximity matching analysis,and a total of 9837 matches are obtained.the goal.It accounts for 5.33% and 5.21% of the respective inputs of AIS and VBD,of which the target of fishing vessels reaches 28.09%,followed by 24.84% of cargo ships,and 47.07% of other types of ships,indicating that the lights of ships at sea are not limited to the targets of fishing ships.In addition,the analysis shows that large and medium-sized(ships greater than 30 meters)accounted for 64.64% of ships,and Chinese ships accounted for 45.02%;(2)Fisheries in the study area obtained from the three data scenarios of AIS,VBD,and the integration of AIS and VBD Fishing intensity data,in terms of comparative analysis,the fishing intensity information obtained by the fusion data is closer to the actual situation;(3)The fishing intensity characteristics of the northern South China Sea presented by the fusion data mainly include the following:(1)High-intensity fishing areas are mostly distributed in Guangdong Province Near shore(10～20 km from Yangjiang,Maoming),around Hainan Island(10～30 km nearshore of Danzhou,Sanya,Lingshui Li Zu),near shore of Guangxi Zhuang Autonomous Region(10～30 km from Beihai,Weizhou Island)).In addition,the high-intensity fishing areas within 30 km of the coastal area mostly show the characteristics of “clumps”;(2)High-intensity fishing during the summer fishing closure/fishing ban period is mostly distributed in the Vietnamese waters,the Sino-Vietnamese maritime border and the common fishing area;(3)All in 2018 The monthly fishing intensity varies greatly and the characteristics are obvious.Among them,the high-intensity fishing in mid-January and February from January to April mainly showed the characteristics of "clumps",while in March and April,the "clumps" expanded outward and formed a "stripe" trend.The area of high-intensity fishing was It has also expanded.From September to December,the high-intensity fishing areas have been distributed within 30 km of the coast of Yangjiang and Maoming,Guangdong Province;(4)Analysis of fishing intensity data produced by fusion data shows that the fishing intensity in the waters within the borders of China during the fishing ban has increased significantly Changes,but near the maritime boundary and common fishing areas,China and Vietnam still need to coordinate.