基于夜间灯光数据的南海渔业捕捞动态变化研究

发布时间：2018-08-10 20:29

【摘要】：南海是我国重要的渔业资源基地之一,渔业资源保护和渔业作业安全关系着我国渔业经济稳定、人民财产安全。然而,随着南海周边国家鼓励并加快其深海渔业资源的开发,对渔业资源的争夺向深水区迈进,我国渔业资源被掠夺事件频发,这已严重威胁我国渔业资源安全和海洋主权完整。针对南海渔业资源过度捕捞的开发形势、南海渔业作业空间信息匮乏等现象,本研究通过Suomi NPP卫星VIIRS DNB夜间灯光数据提取了南海夜间渔船作业点信息;采用重点渔场分析策略,实现南海夜间灯光渔场的月季动态变化分析;结合不同渔区划分结果,从点、面、区域三个维度,动、静结合地分析了渔场时空动态变化规律和南海周边国家和地区夜间灯光捕捞时空变化规律。以期为南海渔业资源的开发、海洋渔业冲突的维权与海洋安全管理提供支撑和决策辅助。研究内容包括:(1)根据渔船夜间捕捞作业在夜间灯光数据中的特征,采用均值滤波及阈值提取等方法,剔除干扰的虚警因子,提取了海上渔船灯光信息,并在此基础上分析了南海夜间渔业生产的季节特征。(2)基于南海夜间渔船灯光提取结果,经过核密度分析,采用夜间灯光重点渔场分析策略,进行夜间灯光渔船作业动态变化研究,通过作业强度峰值点提取及阈值分割,提取了南海夜间灯光重点渔场。在此基础上,对比重点渔场的月季分区域范围变化,分析了南海夜间灯光渔场的月季动态。(3)按照不同的渔区划分方法(按水深划分和按地理位置及作业习惯划分),划分了南海主要渔区。基于不同渔区划分的南海夜间灯光捕捞作业及强度进一步分析;针对南海周边重点渔业生产国家和地区夜间渔业生产,进行时空动态变化分析,从而建立南海夜间周边国家或地区渔区数据集。研究结果表明:(1)南海夜间灯光渔业生产季节变化明显,按生产旺盛程度顺序:春季(32.11%)秋季(26.28%)夏季(24.23%)冬季(17.39%)。南海夜间灯光渔业生产强度年际变化趋势相似,大部分水域年内呈现双峰分布规律。越南东部和泰国湾年内呈现单周期分布,其中,泰国湾峰值出现时间与其他水域不同步。(2)南海夜间灯光渔业空间上具有条带和团块状分布、且集聚性强的特点。重点渔场具有明显扩张又收缩的周期动态变化特征:珠江口附近海域特点是"多点分散,连接扩张,纬向条带聚集分布";北部湾特点是"团块状聚集扩张";越南东部特点是"多点分散,连接扩张,经向条带聚集分布";泰国湾特点是"多点分散,连接扩张,沿岸向中心团状聚集分布"。(3)夜间灯光渔业生产广泛分布在整个南海海域,其捕捞强度按不同的水深,从强到弱依次为:近海(51.90%)沿岸(37.52%)深海(5.67%);按周边国家地理位置和作业习惯,前四位从强到弱依次为:中国禁渔区(12°N以北)(38.87%)、越南(22.46%)、印度尼西亚(11.56%)、泰国(11.03%)。南海夜间灯光渔业总体上呈现年内双周期分布规律,是中国实行休渔制度的主要结果,对保护渔业资源至关重要。
[Abstract]:The South China Sea is one of the most important fishery resource bases in China. The protection of fishery resources and the safety of fishery operation are closely related to the stability of fishery economy and the safety of people's property. However, with the encouragement and acceleration of the exploitation of deep-sea fishery resources by the countries around the South China Sea, the competition for fishery resources is moving towards the deep-water areas, and the fishery resources are plundered frequently. In view of the overfishing situation in the South China Sea and the lack of spatial information of fishery operations in the South China Sea, this study extracts the information of night fishing vessel operation points in the South China Sea from the night light data of the Suomi NPP satellite VIIRS DNB, and adopts the key fishery analysis strategy. In order to explore the fishery resources in the South China Sea and conflict with the marine fishery, the dynamic changes of the fishery and the nocturnal light fishing in the countries and regions around the South China Sea were analyzed from three dimensions of point, area and region. The research contents include: (1) According to the characteristics of nocturnal light data of fishing vessels, the false alarm factor of interference is eliminated by means of mean filter and threshold extraction, and the light information of fishing vessels is extracted. On this basis, the nocturnal fishery production in the South China Sea is analyzed. (2) Based on the results of light extraction from night fishing boats in the South China Sea, the dynamic changes of night light fishing boats were studied by using nuclear density analysis and night light key fishing grounds analysis strategy. The key night light fishing grounds in the South China Sea were extracted by peak point extraction and threshold segmentation. (3) The main fishing areas in the South China Sea were divided according to different fishing area division methods (according to water depth, geographical location and operating habits). The night light fishing operations and intensity in the South China Sea were further analyzed based on different fishing areas. The results show that: (1) The seasonal variation of nocturnal light fishery production in the South China Sea is obvious, in the order of production vigor: spring (32.11%) autumn (26.28%) summer (24.23%) winter (17.3%). The interannual variation trend of nocturnal light fishery production intensity in the South China Sea was similar, and most of the waters showed a bimodal distribution pattern in the year. The main fishing grounds are characterized by obvious periodic dynamic changes of expansion and contraction: the sea area near the Pearl River Estuary is characterized by "multi-point dispersion, connection expansion, zonal band aggregation and distribution"; the Beibu Gulf is characterized by "mass aggregation and expansion"; the eastern Vietnam is characterized by "multi-point dispersion, connection expansion, meridional band aggregation and distribution"; (3) The nocturnal light fishery production is widely distributed in the whole South China Sea, and the fishing intensity is in the order of strength to weakness: offshore (51.90%) coastal (37.52%) deep sea (5.67%); and the top four fisheries are in the order of strength to weakness according to the geographical position and operating habits of the surrounding countries. The nocturnal light fishery in the South China Sea generally presents a two-cycle distribution pattern within a year, which is the main result of China's Fishing Moratorium System and is of vital importance to the protection of fishery resources.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S97

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