Ydesen Kristina S, Wisniewska Danuta M, Hansen Janni D, Beedholm Kristian, Johnson Mark, Madsen Peter T
Zoophysiology, Department of Bioscience, Aarhus University, C. F. Moellers Alle 3, Building 1131, 8000 Aarhus C, Denmark
Zoophysiology, Department of Bioscience, Aarhus University, C. F. Moellers Alle 3, Building 1131, 8000 Aarhus C, Denmark Section for Marine Mammal Research, Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
J Exp Biol. 2014 Jul 1;217(Pt 13):2239-43. doi: 10.1242/jeb.100016. Epub 2014 Apr 15.
A key component in understanding the ecological role of marine mammal predators is to identify how and where they capture prey in time and space. Satellite and archival tags on pinnipeds generally only provide diving and position information, and foraging is often inferred to take place in particular shaped dives or when the animal remains in an area for an extended interval. However, fast movements of the head and jaws may provide reliable feeding cues that can be detected by small low-power accelerometers mounted on the head. To test this notion, a harbour seal (Phoca vitulina) was trained to wear an OpenTag (sampling at 200 or 333 Hz with ± 2 or ± 16 g clipping) on its head while catching fish prey in front of four underwater digital high-speed video cameras. We show that both raptorial and suction feeding generate jerk (i.e. differential of acceleration) signatures with maximum peak values exceeding 1000 m s(-3). We conclude that reliable prey capture cues can be derived from fast-sampling, head-mounted accelerometer tags, thus holding a promising potential for long-term studies of foraging ecology and field energetics of aquatic predators in their natural environments.
理解海洋哺乳动物捕食者生态作用的一个关键要素是确定它们在何时何地以及如何在时空上捕获猎物。鳍足类动物身上的卫星标签和存档标签通常仅能提供潜水和位置信息，觅食行为往往是根据特定形状的潜水或动物在某一区域停留较长时间来推断的。然而，头部和下颚的快速运动可能会提供可靠的进食线索，这些线索可以被安装在头部的小型低功率加速度计检测到。为了验证这一概念，一只港海豹（Phoca vitulina）经过训练，在四台水下数字高速摄像机前捕食鱼类时，在其头部佩戴一个OpenTag（采样频率为200或333Hz，±2或±16g限幅）。我们发现，猛扑式进食和吸食式进食都会产生加加速度（即加速度的微分）信号，其最大峰值超过1000 m s(-3)。我们得出结论，可靠的猎物捕获线索可以从快速采样的头戴式加速度计标签中获得，因此在自然环境中对水生捕食者的觅食生态和野外能量学进行长期研究具有广阔的前景。
