Spatial-temporal features and potential pressure of marine vessel activities based on AIS and multi-scales spatial model

Based on the ship automatic identification system (AIS) data,the spatial-temporal feature of fishing vessels and commercial ships activities were identified,and the potential pressure caused by marine ships on ecological red line sea area and marine functional zone in Laizhou Bay were assessed by using GIS spatial analysis and geospatial simulation methods. Results show that maritime vessel activities in Laizhou Bay are concentrated in the southwest sea area and marine functional areas,such as port shipping area,agricultural fishery area and so on; the daily and seasonal variations of fishing vessels are more obvious; the potential pressure of the marine vessel activities in the southwestern sea area of the Laizhou Bay and the northwest of Longkou port area is greater. It is recommended to strengthen the supervision of fishing activities and fishing operations in Laizhou Bay in the 9-11 months of the year. Ecological environment quality monitoring of marine ecological red line areas such as Yellow River Estuary and Laizhou shoal should be carried out,and prevent the harmful effect resulted from commercial vessel activities on the marine environment of culture zone and oceanic pasture surrounding the port and shipping zone

Spatiotemporal distribution of fishing grounds in the Bohai Sea and its adjacent waters based on AIS

Automatic identification system(AIS)is a new type of navigation aid system applied to ship-toship and ship-to-shore. It can monitor vessel activity in real time and plays an increasingly important role in vessel collision avoidance, vessel monitoring, and maritime management. In the past ten years, the popularization and application of AIS transmitters has made AIS-based dynamic trajectory data valuable for scientific research in marine traffic management,marine fisheries management,and marine spatial planning management. With its high spatial and temporal resolution,AIS data provides a good source to reveal the characteristics of maritime traffic activities and fishing intensity. Since the introduction of AIS,significant progress has been made regarding the use of AIS data for identifying fishing behavior,quantifying fishing intensity,and assessing marine ecological stress. However,previous studies lack a description of the overall spatial and temporal distribution pattern of fishing activities in coastal sea areas,which affects the efficiency of marine fishing activity management and marine ecological protection in regional waters. The Bohai Sea and its adjacent waters is one of the important distribution areas of fishing grounds in China,with abundant fishing resources,extensive distribution of fishing ports and fishing vessels, and intensive fishing activities. Nevertheless,in recent decades,due to the impact of overfishing and land-source pollution,fishery resources have been seriously degraded. It is an urgent need to understand the distribution and level of overall fishing activity in regional waters,so as to provide decision-making support for marine fishing activities,marine ecological environment protection,and the restoration of marine fisheries resources. Based on AIS data from marine vessels in the Bohai Sea and its adjacent waters in 2014 and 2018,this study mapped the range of the fishing ground,and analyzed the temporal and spatial distribution characteristics of fishing grounds and their influence factors. First,the speed threshold under fishing states was determined based on the speed frequency density distribution of fishing vessels and a Gaussian mixed model. Secondly,the kernel density estimation and hot spot analysis were combined to map fishing grounds. The standard deviation ellipse method was used to calculate the spatial distribution center of fishing grounds. Then the distribution of fishing grounds for the months and quarters of 2018 and the same MMSI information for 2014 and 2018 were mapped. Finally,based on the statistical analysis and the aggregation index,the quantitative structure and spatial distribution characteristics of fishing grounds were analyzed,and the factors that caused the differences in the spatial and temporal patterns of fishing grounds were discussed. The results showed that there were significant monthly and quarterly differences in the spatial distribution of fishing grounds in the Bohai Sea and its adjacent waters. It was mainly distributed in Yanwei near-shore area and sea area near the Bohai Strait. Except for the summer fishing moratorium period from May to August,the average percentage of the sea area near the Bohai Strait and Yanwei near-shore fishing grounds in the total area of all fishing grounds each month was about 52.10%. While the scale of fishing activity in the Bohai Sea was small,it was scattered only in the coastal waters of Qinhuangdao,northern areas of Huanghua,and Laizhou Bay. The large-scale fishing activities were mainly concentrated from September to December after the summer fishing moratorium,with widespread fishing grounds and marked changes in spatial morphology. Among them,the fishing grounds in September were the largest,with an area of about 15 355.29 km~2. In October,fishing grounds had the highest level of clustering, and the aggregation degree index reached 37.49

Experimental Study on the Influence of Initial Pressure on the Formation Process of C_3H_8 Hydrate

In order to study the influence of initial pressure on the formation process of C3H8 hydrate, the formation process of C3H8 has been investigated in visualization installation in the system of pure water and SDS of 1 950×10^-6 under different initia

Mapping Method of Fishing Grounds based on Marine AIS Data

Automatic Identification System (AIS) is a ship-to-ship and ship-to-shore system used for ship monitoring. It can automatically and continuously broadcast static and dynamic information about the vessel's position and movement, as well as voyage-related information. More and more research suggests that AIS is not only an effective tool for maritime traffic supervision, but also a good data source for the study of maritime traffic and its related industrial activities. In China, the application of AIS equipment is relatively late. The research based on AIS data mainly focuses on the maritime traffic safety management, such as vessel collision avoidance and traffic flow statistics, while there are few reports in the fishery field. In order to provide technical support for the protection and recovery of inshore fishery resources in China, it is urgent to excavate the information value of AIS data and carry out the research on the spatiotemporal pattern of inshore fishing activities based on AIS data. Therefore, based on AIS data of fishing vessels at sea, this study used the Gaussian Mixed Model (GMM) to identify fishing behavior of fishing vessels and determine the speed threshold of fishing vessels in fishing activities. This study proposed a method combining Kernel Density Estimation (KDE) and Hot Spot Analysis (HSA) to map fishing grounds. The results show that, firstly, compared with single KDE or HSA method, the combination method combined the distance attenuation effect of KDE with quantitative statistical index of HSA, which can not only avoid the problem of range definition of fishing grounds in the KDE process, but also improve the efficiency of data analysis in the HSA process and the scattered distribution effect of fishing grounds in the extraction results of the HSA. The combination method had better application effects and higher efficiency in the mapping of fishing grounds. It provided a quick and simple evaluation method for the rapid acquisition of marine fishing information and the effectiveness evaluation of fishery resources protection and management measures. Secondly, based on the AIS data from September to December 2018, the combination method was used to map the spatiotemporal distribution of fishing grounds around the Bohai Strait. The study found that the fishing grounds around the Bohai Strait were mainly distributed in the inshore areas of Yanwei and the Bohai Strait. The distribution range of concentrated fishing activities in traditional fishing grounds of the Bohai Sea is relatively small, and the distribution range and spatial morphological characteristics of fishing grounds had some variabilities in different months. The results can provide technical methods and decision support for fishing management and marine ecological protection around the Bohai Strait

Situation evaluation on the marine spatial development and utilization in the Laizhou Bay

基于GIS平台绘制莱州湾海域空间开发利用现状分布图,从海域空间开发利用结构、强度和协调性三方面对莱州湾海域空间开发利用现状进行了分析和评价。结果表明:莱州湾海域用海类型基本齐全,但是开发利用结构规模不均衡,开放式养殖、盐业和交通运输用海是其主要类型;莱州湾海域空间开发利用强度较高,呈现出中部>整体>东部>西部海域的特点;海域开发利用活动之间及其与海洋功能区划、海域自然属性分布之间存在着不协调现象。未来,莱州湾海域开发利用需要优化调整用海结构和布局,提高产业开发利用层次;严格限制新增围填海工程,加强对自然岸线资源的保护,加大对海域环境整治和生物资源修复的支持力度

Assessment of potential pressure caused bysea use activities on the eco-environment of bays: A case studyin Laizhou Bay,China

The potential pressure caused by sea use activities on marine eco-environment in Laizhou Bay was quantitatively evaluated based on GIS and geospatial modeling by combining the spatial distribution of marine ecological red line zone.We firstly identified the spatial distribution patterns of all anthropogenic pressures as well as their potential impact on key marine habitats.The general characteristic of spatial distribution of potential anthropogenic pressure on the eco-environment in Laizhou Bay can be described as that in the offshore area is higher than that in the far-shore area and the sequence from high to low is:the bay-head,the east area,the west area.Overall,the high pressure area is concentrated in the sea area within 10 km and the water depth within 5 m.It is worthy to note that a few of marine ecological red line zones,such as marine special protected areas,natural reserves,and important estuarine ecosystems,have already threatened by pressure caused by sea aquaculture and salt industry.The study reveals the spatial distribution pattern of the potential pressure of sea use activities on the marine ecological environment in Laizhou Bay.Accordingly,a few policy suggestions are also proposed at the end to implement the spatial planning of marine ecological red line zones and regulate utilization of sea area

莱州湾海域空间开发利用现状评价

基于GIS平台绘制莱州湾海域空间开发利用现状分布图,从海域空间开发利用结构、强度和协调性三方面对莱州湾海域空间开发利用现状进行了分析和评价。结果表明:莱州湾海域用海类型基本齐全,但是开发利用结构规模不均衡,开放式养殖、盐业和交通运输用海是其主要类型;莱州湾海域空间开发利用强度较高,呈现出中部>整体>东部>西部海域的特点;海域开发利用活动之间及其与海洋功能区划、海域自然属性分布之间存在着不协调现象。未来,莱州湾海域开发利用需要优化调整用海结构和布局,提高产业开发利用层次;严格限制新增围填海工程,加强对自然岸线资源的保护,加大对海域环境整治和生物资源修复的支持力度