ABARES Fisheries Status Report map data: Southern Bluefin Tuna Fishery (SBTF): fishing intensity and maximum area fished, annual map data for 2010 to 2020

This dataset presents maps of fishing intensity and maximum area fished of ocean waters within the Southern Bluefin Tuna Fishery (SBTF).

The data were prepared as part of the annual ABARES Fishery Status Report series, which provides an independent evaluation of the biological and economic status of fish stocks managed solely or jointly by the Australian Government. The data were produced by ABARES from data supplied by the Australian Fisheries Management Authority (AFMA).

The data are presented annually, by fishing season which runs from 1 December to 30 November for this fishery. For example, for this fishery, the 2019-20 year runs from 1 December 2019 to 30 November 2020.

The data are polygon vector format, stored in an ESRI file geodatabase, prepared using ArcGIS Desktop ArcMap version 10.6.

There are two sectors in this fishery: purse-seining in the waters off eastern South Australia and longlining off the southern end of the east coast of Australia. These sectors are referred to, respectively, as purse-seine and longline.
Fishing intensity in this fishery is defined differently in the two sectors of the fishery. Fishing intensity in the purse-seine sector is defined as the total fishing effort, measured as the number of operations, divided by the total area fished in square kilometres. Fishing intensity in the longline sector is defined as the total catch, measured in kilograms, divided by the total area fished in square kilometres. In both cases, effort and catch are measured over the period of the fishing season. Fishing intensity is presented as classified data in low, medium and high intensity classes. The data attributes include the class, the range of values in the class and the unit of measure. The classification used may vary from year to year, depending on a range of environmental and economic factors.

Maximum area fished is defined as the maximum area within which fishing occurred during a given fishing season as polygon cells of one degree of longitude by one degree of latitude (approximately 111 kilometres x 111 kilometres). A cell is included if any fishing activity occurred anywhere within that one degree by one degree cell. Note that cells included in this dataset may also partially cover land.

The data supplied by AFMA were filtered to remove activity by fewer than five boats within the area of analysis in order to conform with AFMA’s Information Disclosure Policy (https://www.afma.gov.au/about/fisheries-management-policies/information-disclosure-fisheries-management-paper).

本数据集提供了南蓝鳍金枪鱼渔业（Southern Bluefin Tuna Fishery, SBTF）管辖海域的捕捞强度与最大捕捞面积分布图。

本数据集作为澳大利亚农业与资源经济科学局（Australian Bureau of Agricultural and Resource Economics and Sciences, ABARES）年度渔业状况报告系列的组成部分编制完成，该系列报告可独立评估由澳大利亚政府单独或联合管理的鱼类种群的生物学与经济现状。数据集由ABARES基于澳大利亚渔业管理局（Australian Fisheries Management Authority, AFMA）提供的原始数据制作生成。

本数据集按捕捞年度逐年发布，该渔业的捕捞季为每年12月1日至次年11月30日。例如，该渔业的2019-20捕捞季对应2019年12月1日至2020年11月30日。

数据采用多边形矢量格式，存储于ESRI文件地理数据库中，使用ArcGIS Desktop ArcMap 10.6版本编制。

该渔业分为两个作业分区：南澳大利亚州东部海域的围网作业，以及澳大利亚东海岸南端的延绳钓作业，二者分别简称为围网分区与延绳钓分区。

两个作业分区的捕捞强度定义存在差异：围网分区的捕捞强度以总捕捞作业次数计量的总捕捞努力量，除以以平方千米为单位的总捕捞面积；延绳钓分区的捕捞强度则以千克计量的总渔获量，除以以平方千米为单位的总捕捞面积。两类指标的统计周期均为完整捕捞季。捕捞强度以低、中、高三级分类数据形式呈现，数据属性包含分类等级、该等级的数值区间与计量单位。分级标准每年可能因一系列环境与经济因素发生调整。

最大捕捞面积指给定捕捞季内发生捕捞作业的最大范围，以经度1度×纬度1度（约111千米×111千米）的多边形网格单元表示。若1度×1度的网格单元内存在任何捕捞活动，则将其纳入统计范围。需注意，本数据集包含的网格单元可能会部分覆盖陆地。

为符合澳大利亚渔业管理局（AFMA）的信息披露政策（https://www.afma.gov.au/about/fisheries-management-policies/information-disclosure-fisheries-management-paper），AFMA提供的原始数据已进行过滤处理，剔除了分析区域内作业船只数量少于5艘的捕捞活动。