Collaborative Research Weddell Seal Foraging: Behavioral and Energectic Strategies for Hunting Beneath the Antarctic Fast-Ice

威德尔海豹（Leptonychotes weddellii）已经适应了一个对呼吸空气的捕食者来说非常具有挑战性的环境，为了在南极海岸广阔的、未破碎的坚冰下有效地觅食。这些适应能力使威德尔海豹能够在憋气20分钟或更长时间的情况下在深海捕食猎物。这类似于狮子或其他大型陆地捕食者在定位、追捕和捕获猎物时屏住呼吸。此外，威德尔海豹在潜水结束时必须回到同一个洞，或者知道其他呼吸孔的位置。如果找不到呼吸孔，海豹就会溺水而死。这项研究将调查威德尔海豹在南极快冰环境中觅食的行为和能量适应。为了实现这一目标，我们将在觅食潜水过程中测量威德尔海豹的水下行为、运动表现（游泳速度、划水频率和幅度、三维运动）和能量代谢。对不同环境条件和猎物类型下的一般觅食策略、觅食行为、觅食机制、游泳方式、觅食代谢成本和觅食效率的假设进行了检验。到目前为止，还不可能详细调查海洋哺乳动物的觅食行为。为了完成这项研究，一个小型视频系统和数据记录器将被安装在海豹的背部，并在南极麦克默多湾一个孤立的冰洞自愿潜水期间测量氧气消耗。在一个孤立的冰洞里放置一只带仪器的海豹是研究威德尔海豹潜水行为的标准方案。视频系统和数据记录器将记录下海豹头部的视频图像和动物前方的直接环境。此外，仪器将记录时间、深度、游泳速度、指南针方位、水温、胃温和环境声音。对深度、游泳速度和方位等数据的计算机分析将使调查人员能够重建海豹潜水的三维水下路径。这项新技术已全面投入使用，并已在其他海洋哺乳动物身上得到应用。对海洋哺乳动物觅食行为和猎物的观察一直是并将继续是海洋哺乳动物觅食生态学研究进展的主要障碍。威德尔海豹可能是研究深潜鳍足动物觅食行为和能量学的最佳物种，因为：1)它们潜水能力的数据是可用的；2)麦克默多湾的隔离冰洞协议使记录仪能够可靠地连接和恢复；3)当它们被放置在隔离的冰洞里时，它们每天都要潜水觅食。这项拟议的研究将调查觅食的行为和能量方面，以更好地理解在有限的大气氧气限制下获得深度食物资源的特殊挑战。此外，该研究将极大地促进我们对威德尔海豹在南极快冰环境中作为大型捕食者的觅食生态的理解。

Davis 9614857 Fuiman 9708151 Williams 9618384 To forage efficiently beneath the extensive, unbroken fast ice along the Antarctic coast, Weddell seals (Leptonychotes weddellii)have adapted to an environment that is very challenging for an air-breathing predator. These adaptations enable Weddell seals to hunt for prey at depth while holding their breath for 20 minutes or longer. This is analogous to a lion or other large terrestrial predator holding its breath while it locates, pursues and captures prey. In addition, Weddell seals must return to the same hole at the end of a dive or know the location of other breathing holes. Failure to locate a breathing hole will result in a seal's death by drowning. This study will investigate the behavioral and energetic adaptations that enable Weddell seals to forage in the Antarctic fast-ice environment. To achieve this goal,the underwater behavior, locomotor performance (swimming velocity, stroke frequency and amplitude, and three dimensional movements)and energy metabolism of Weddell seals will be measured during foraging dives. Hypotheses on general foraging strategies, searching behavior, searching mechanics, modes of swimming, metabolic costs of foraging and foraging efficiency for different environmental conditions and prey type will be tested. Until now, it has not been possible to investigate the foraging behavior of marine mammals in detail. To accomplish this study, a small video system and data logger will be attached to the seals' backs and oxygen consumption will be measured during voluntary dives from an isolated ice hole in McMurdo Sound, Antarctica. Placing an instrumented seal in an isolated ice hole is a standard protocol for studying the diving behavior of Weddell seals. The video system and data logger will record video images of the seal's head and the immediate environment in front of the animal. In addition, the instrument will record time, depth, swim speed, compass bearing, water tem perature, stomach temperature and ambient sound. Computer analysis of data on depth, swim speed and bearing will enable investigators to reconstruct the three-dimensional, underwater path of seals'dives. This new technology is fully operational and has been used on other marine mammals. Observing the foraging behavior and prey of marine mammals has been and continues to be a major obstacle to the advancement of studies on their foraging ecology. The Weddell seal may be the single best species in which to study the foraging behavior and energetics of deep diving pinnipeds because: 1) data is available on their diving ability, 2) the isolated-ice-hole protocol in McMurdo Sound enables recorders to be attached and recovered reliably, and 3) they make daily foraging dives when placed in the isolated ice hole. The proposed study will investigate both behavioral and energetic aspects of foraging to obtain a better understanding of the special challenges of obtaining food resources at depth while being constrained by limited access to atmospheric oxygen. In addition, this study will greatly advance our understanding of the foraging ecology of Weddell seals as large predators in the Antarctic fast-ice environment.