Data from: Processing of acceleration and dive data on-board satellite relay tags to investigate diving and foraging behaviour in free-ranging marine predators

1. Biologging technologies are changing the way in which the marine environment is observed and monitored. However, because device retrieval is generally required to access the high resolution data they collect, use is generally restricted to those animals that predictably return to land. Data abstraction and transmission techniques aim to address this, although currently these are limited in scope and do not incorporate, for example, acceleration measurements which can quantify animal behaviours and movement patterns over fine-scales.
2. In this study, we present a new method for the collection, abstraction and transmission of accelerometer data from free-ranging marine predators via the Argos satellite system. We test run the technique on 20 juvenile southern elephant seals Mirounga leonina from the Kerguelen Islands during their first months at sea following weaning. Using retrieved archival data from nine individuals that returned to the colony, we compare and validate abstracted transmissions against outputs from established accelerometer processing procedures.
3. Abstracted transmissions included estimates, across five segments of a dive profile, of time spent in prey catch attempt (PrCA) behaviours, swimming effort and pitch. These were then summarised and compared to archival outputs across three dive phases: descent, bottom and ascent. Correlations between the two datasets were variable but generally good (dependent on dive phase, marginal R2 values of between 0.45 and 0.6 to > 0.9) and consistent between individuals. Transmitted estimates of PrCA behaviours and swimming effort were positively biased to those from archival processing. 4. Data from this study represents some of the first remotely transmitted quantifications from accelerometers. The methods presented and analysed can be used to provide novel insight toward the behaviours and movements of free-ranging marine predators, such as juvenile southern elephant seals, from whom logger retrieval is challenging. Future applications could however benefit from some adaption, particularly to reduce positive bias in transmitted PrCA behaviours and swimming effort, for which this study provides useful insight.

1. 生物记录技术（Biologging technologies）正在改变海洋环境的观测与监测方式。然而，由于获取其采集的高分辨率数据通常需要回收设备，这类技术的应用往往局限于可预期返回陆地的动物。数据提取与传输技术旨在解决这一难题，但目前此类技术的应用范围有限，例如无法纳入可精细量化动物行为与运动模式的加速度测量数据。
2. 本研究提出了一种全新的方法，可通过阿尔戈斯卫星系统（Argos satellite system）对自由活动的海洋捕食者的加速度计数据进行采集、提取与传输。我们于凯尔盖朗群岛（Kerguelen Islands）的20只断奶后首月出海的幼年南象海豹（Mirounga leonina）身上对该技术进行了试运行。通过回收其中9只返回繁殖群的个体的存档数据，我们将提取传输得到的结果与成熟的加速度计处理流程输出结果进行对比与验证。
3. 提取传输的数据涵盖了潜水剖面5个分段中，猎物捕捉尝试（PrCA）行为耗时、游泳用力程度与俯仰角的估算值。随后我们对这些数据进行汇总，并与存档数据在3个潜水阶段（下潜、底栖停留与上升）的输出结果进行对比。两组数据集的相关性存在差异，但整体表现良好（依潜水阶段不同，边际决定系数R²介于0.45~0.6至>0.9之间），且个体间结果一致。传输得到的PrCA行为与游泳用力程度估算值相较于存档处理结果存在正向偏倚。
4. 本研究的数据是首批通过远程传输获取的加速度计量化数据之一。本文提出并分析的方法可用于深入解析自由活动的海洋捕食者（如幼年南象海豹）的行为与运动模式——这类动物的记录仪回收难度极大。不过未来的应用可通过部分适配进行优化，尤其是降低传输得到的PrCA行为与游泳用力程度估算值的正向偏倚，本研究为此提供了具有参考价值的思路。