Cox Sam L, Orgeret Florian, Gesta Mathieu, Rodde Charles, Heizer Isaac, Weimerskirch Henri, Guinet Christophe
Centre d'Etudes Biologique de Chizé U.M.R. 7372 - CNRS & Universitié de La Rochelle Villiers-en-Bois France.
Wildlife Computers Redmond WA USA.
Methods Ecol Evol. 2018 Jan;9(1):64-77. doi: 10.1111/2041-210X.12845. Epub 2017 Jul 27.
Biologging technologies are changing the way in which the marine environment is observed and monitored. However, because device retrieval is typically required to access the high-resolution data they collect, their 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.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 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.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 values of between .45 and .6 to >.9) and consistent between individuals. Transmitted estimates of PrCA behaviours and swimming effort were positively biased to those from archival processing.Data from this study represent some of the first remotely transmitted quantifications from accelerometers. The methods presented and analysed can be used to provide novel insight towards 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.
生物记录技术正在改变观察和监测海洋环境的方式。然而，由于通常需要取回设备才能获取它们收集的高分辨率数据，因此其使用一般仅限于那些可预测会返回陆地的动物。数据提取和传输技术旨在解决这一问题，尽管目前这些技术的范围有限，并且没有纳入例如加速度测量，而加速度测量可以在精细尺度上量化动物行为和运动模式。在本研究中，我们提出了一种通过Argos卫星系统从自由放养的海洋捕食者收集、提取和传输加速度计数据的新方法。我们在20只来自克尔格伦群岛的幼年南象海豹断奶后的头几个月在海上时对该技术进行了测试运行。利用从返回栖息地的9只个体中取回的存档数据，我们将提取的传输数据与既定加速度计处理程序的输出进行了比较和验证。提取的传输数据包括在潜水剖面的五个部分中，用于尝试捕食行为（PrCA）、游泳努力程度和俯仰的时间估计。然后对这些数据进行汇总，并与三个潜水阶段（下降、底部和上升）的存档输出进行比较。两个数据集之间的相关性各不相同，但总体良好（取决于潜水阶段，边际值在0.45至0.6之间，至大于0.9），并且个体之间保持一致。传输的PrCA行为和游泳努力程度估计值相对于存档处理得到的结果存在正偏差。本研究的数据代表了加速度计的一些首批远程传输的量化数据。所提出和分析的方法可用于为自由放养的海洋捕食者（如幼年南象海豹）的行为和运动提供新的见解，从这些动物身上取回记录器具有挑战性。然而，未来的应用可能会受益于一些调整，特别是减少传输的PrCA行为和游泳努力程度中的正偏差，本研究为此提供了有用的见解。
