Kadar Julianna, Ladds Monique, Mourier Johann, Day Joanna, Brown Culum
Department of Biological Sciences Macquarie University Marsfield Australia.
Department of Conservation National Office Wellington New Zealand.
Ecol Evol. 2019 Jul 27;9(16):8933-8944. doi: 10.1002/ece3.5323. eCollection 2019 Aug.
Distinguishing the factors that influence activity within a species advances understanding of their behavior and ecology. Continuous observation in the marine environment is not feasible but biotelemetry devices provide an opportunity for detailed analysis of movements and activity patterns. This study investigated the detail that calibration of accelerometers measuring root mean square (RMS) acceleration with video footage can add to understanding the activity patterns of male and female Port Jackson sharks () in a captive environment. Linear regression was used to relate RMS acceleration output to time-matched behavior captured on video to quantify diel activity patterns. To validate captive data, diel patterns from captive sharks were compared with diel movement data from free-ranging sharks using passive acoustic tracking. The RMS acceleration data showed captive sharks exhibited nocturnal diel patterns peaking during the late evening before midnight and decreasing before sunrise. Correlation analysis revealed that captive animals displayed similar activity patterns to free-ranging sharks. The timing of wild shark departures for migration in the late breeding season corresponded with elevated diel activity at night within the captive individuals, suggesting a form of migratory restlessness in captivity. By directly relating RMS acceleration output to activity level, we show that sex, time of day, and sex-specific seasonal behavior all influenced activity levels. This study contributes to a growing body of evidence that RMS acceleration data are a promising method to determine activity patterns of cryptic marine animals and can provide more detailed information when validated in captivity.
区分影响物种内活动的因素有助于增进对其行为和生态的理解。在海洋环境中进行连续观测是不可行的，但生物遥测设备为详细分析运动和活动模式提供了机会。本研究调查了通过视频 footage 校准测量均方根（RMS）加速度的加速度计，能为理解圈养环境中雄性和雌性杰克逊港鲨鱼（）的活动模式增添哪些细节。线性回归用于将 RMS 加速度输出与视频中记录的时间匹配行为相关联，以量化昼夜活动模式。为了验证圈养数据，使用被动声学跟踪将圈养鲨鱼的昼夜模式与自由游动鲨鱼的昼夜运动数据进行比较。RMS 加速度数据显示，圈养鲨鱼呈现夜间昼夜模式，在午夜前的深夜达到峰值，日出前下降。相关性分析表明，圈养动物与自由游动鲨鱼表现出相似的活动模式。野生鲨鱼在繁殖后期迁徙出发的时间与圈养个体夜间升高的昼夜活动相对应，表明圈养中有某种形式的迁徙不安。通过直接将 RMS 加速度输出与活动水平相关联，我们表明性别、一天中的时间以及特定性别的季节性行为都会影响活动水平。本研究为越来越多的证据做出了贡献，即 RMS 加速度数据是确定隐秘海洋动物活动模式的一种有前景的方法，并且在圈养中得到验证时可以提供更详细的信息。
