Blue whale foraging and movement ecology

This archive contains data used in a study of the movement and foraging ecology of blue whales in the eastern North Pacific, specifically the Monterey Bay region off central California, USA. The study was published in Ecology Letters in 2022 and is entitled, “Oceanic giants dance to atmospheric rhythms: Ephemeral wind-driven resource tracking by blue whales.” As of this writing, the article does not yet have a DOI. <br> The published analyses were conducted in MATLAB. However, to make the data and reproducibility of analyses more widely accessible, both data and processing code have been translated into R for this archive. <br> 1) Acoustic vector sensor (AVS) data from the MARS observatory Annual periods of blue whale acoustic presence were analyzed across two years to examine the directional distribution of whale call origin around the MARS cabled observatory. Quality controlled data include the time, bearing, and call index of all manually validated seconds for which the blue whale B-call index exceeded a value of 1.25. Analysis results from these data appear in Figures 4 and 5 of the paper. The data files are AVS_2019-2020.RData and AVS_2020-2021.RData, and the example processing code is AVSprocessing.R. <br> 2) Modeled received levels at the MARS observatory The geographic domain over which received signal is sufficient to reliably estimate the direction of blue whale B-call origin from the MARS cabled observatory was approximated by modeling of acoustic transmission loss. These data appear in Figure 2C of the paper. Model results represent received level (underwater dB) at the MARS cabled observatory, assuming appropriately specified intensity, depth, and frequency of the sound source (blue whale B call) and oceanographic physical conditions during the time of year when blue whale calling is most active in the study region. The data file is ModeledReceivedLevel.RData, and the example processing code is ModeledReceivedLevelPlot.R. <br> 3) Animal-borne tag data Data from a biologging tag deployed on a blue whale were used to validate an acoustic vector sensor on the MARS observatory. These data appear in Figure 3 of the paper and include information about whale behaviors (diving, calling, lunge feeding) and surface position from GPS. In addition to data on identified behavioral events, underlying hydrophone and accelerometer data used to identify behaviors during the period of matchup with MARS AVS data are included. The data file is Tag_bw191101-70.RData, and the example processing code is Tag_bw191101-70plot.R. <br> 4) Forage species aggregation data The area scattering (sa) within forage species’ patches in the upper 200 m above the MARS observatory, presented in Figure 5E of the paper, are in the file MARS_sa.RData.

本存档包含用于一项研究的数据集，该研究聚焦美国加利福尼亚州中部近海蒙特雷湾海域的东太平洋蓝鲸活动与觅食生态学。此项研究于2022年发表于《Ecology Letters》，论文标题为《Oceanic giants dance to atmospheric rhythms: Ephemeral wind-driven resource tracking by blue whales》。截至本说明撰写时，该论文尚未获取数字对象标识符（Digital Object Identifier，DOI）。

已发表的分析工作基于MATLAB完成。为提升数据与分析可复现性的普适性，本存档中的数据与处理代码均已转换为R语言实现。

1) 声学矢量传感器（Acoustic Vector Sensor, AVS）数据（源自MARS观测站）
本研究分析了两年间蓝鲸声学出现的年度周期，以探究MARS缆式观测站周边蓝鲸叫声来源的方位分布。经质量控制的数据包含所有经人工验证的有效秒数对应的时间、方位角与叫声指数，其中蓝鲸B叫声指数均高于1.25。基于该数据集得到的分析结果对应论文中的图4与图5。相关数据文件为AVS_2019-2020.RData与AVS_2020-2021.RData，示例处理代码为AVSprocessing.R。

2) MARS观测站模拟接收声级数据
本部分通过声学传输损失建模，近似得到了可通过MARS缆式观测站可靠估算蓝鲸B叫声来源方位的信号接收地理范围。该数据集对应论文中的图2C。模型结果表征了MARS缆式观测站处的接收声级（水下分贝），假设声源（蓝鲸B叫声）的强度、深度与频率参数设置合理，且研究区域内蓝鲸叫声活跃时段的海洋物理条件符合实测状态。相关数据文件为ModeledReceivedLevel.RData，示例处理代码为ModeledReceivedLevelPlot.R。

3) 动物搭载式生物记录标签（biologging tag）数据
本部分使用部署于蓝鲸身上的生物记录标签数据，以验证MARS观测站的声学矢量传感器性能。该数据集对应论文中的图3，包含蓝鲸的行为信息（潜水、鸣叫、突进捕食）与GPS获取的海面位置数据。除已识别的行为事件数据外，还包含用于匹配MARS AVS数据时段内行为识别的原始水听器与加速度计数据。相关数据文件为Tag_bw191101-70.RData，示例处理代码为Tag_bw191101-70plot.R。

4) 饵料物种聚集数据
本部分包含MARS观测站上方200米水层内饵料物种斑块的面积散射系数（area scattering, sa）数据，对应论文中的图5E，存储于文件MARS_sa.RData中。