Recent pace of change in human impact on the world's ocean: Commercial fishing - demersal non-desctructive low-bycatch

These are the stressor and impact data for commercial demersal nondestructive low bycatch fishing for the publication: 'Recent pace of change in human impact on the world's ocean' (Halpern et al. 2019). This stressor describes tonnes of demersal fisheries catch using nondestructive and low bycatch gear types. Catch is standardized by Net Primary Productivity. We describe the stressor intensity of demersal nondestructive low bycatch fishing and the corresponding impact on 21 marine ecosystems over 11 years (2003-2013). To determine annual change in impact, we applied a linear regression model to each raster cell. Code used in analyzing these data is available as a zipped GitHub repository, impact_acceleration-1.0.zip, in this dataset's parent (CITATION HERE). These data include the following: Raw stressor intensity rasters for 2003 to 2013. These rasters are created using scripts located in the 'stressors' folder of the 'impact_acceleration' Github repository. Rescaled stressor intensity rasters for 2003 to 2013. Raw stressor intensities are rescaled to values between 0 and 1, using either known or estimated ecosystem thresholds or upper quantile values from the distribution of global stressor intensity values across years. These rasters are created using scripts located in the 'stressors' folder of the 'impact_acceleration' Github repository. Impact rasters for 2003 to 2013 which describe the impact of the stressor based on the vulnerability of 21 marine ecosystems to the stressor. The impact of the stressor is estimated by multiplying the stressor's intensity by the corresponding ecosystem vulnerability where the ecosystem occurs. The average impact of each stressor, across all ecosystems, is estimated by summing the stressor-by-ecosystem vulnerability combinations and dividing by the number of ecosystems within each cell. These rasters are created using scripts located in the 'impacts' folder of the 'impact_acceleration' Github repository. A trend raster describing the average annual change in impact from 2003 to 2013. This raster is created using scripts located in the 'trend' folder of the 'impact_acceleration' Github repository. Files describing the cumulative impacts and additional stressors are provided in other KNB datasets.本数据集对应论文《近期全球海洋人类影响变化速率》（Halpern等人，2019年）中涉及商业性底栖无破坏性低兼捕捕捞的压力源与影响数据。该压力源以吨为单位统计采用无破坏性、低兼捕渔具类型的底栖渔业捕捞量，捕捞量通过净初级生产力（Net Primary Productivity, NPP）进行标准化处理。本数据集覆盖2003至2013年共11年间的底栖无破坏性低兼捕捕捞压力源强度，以及其对21种海洋生态系统产生的对应影响。为测算影响的年度变化，研究团队对每个栅格单元（raster cell）应用了线性回归模型。本数据集父数据集（引用信息待补充）中包含打包为"impact_acceleration-1.0.zip"的GitHub存储库，内含分析上述数据所用的代码。 本数据集包含以下内容： 1. 2003至2013年的原始压力源强度栅格（raster）数据。此类栅格通过"impact_acceleration" GitHub存储库的"stressors"文件夹内的脚本生成。 2. 2003至2013年的归一化压力源强度栅格数据。原始压力源强度通过已知或估算的生态系统阈值，或基于历年全球压力源强度分布的上分位数数值，被归一化至0至1区间内。此类栅格同样通过"impact_acceleration" GitHub存储库的"stressors"文件夹内的脚本生成。 3. 2003至2013年的影响栅格数据，此类数据基于21种海洋生态系统对该压力源的脆弱性，刻画该压力源所产生的影响。压力源的影响通过将压力源强度与对应栅格单元内生态系统的脆弱性相乘得到；所有生态系统的平均影响则通过求和各压力源-生态系统脆弱性组合的数值，再除以每个栅格单元内的生态系统数量估算得到。此类栅格通过"impact_acceleration" GitHub存储库的"impacts"文件夹内的脚本生成。 4. 趋势栅格数据，用于描述2003至2013年间影响的平均年度变化。此类栅格通过"impact_acceleration" GitHub存储库的"trend"文件夹内的脚本生成。 描述累积影响与其他压力源的相关文件已收录于其他生物复杂性知识网络（Knowledge Network for Biocomplexity, KNB）数据集当中。