DISSERTATION RESEARCH: Fine-Scale Pelagic Predator-Prey Interactions: Hawaiian Spinner Dolphins and the Mesopelagic Boundary Community

“超大规模中上层捕食者-猎物的相互作用：夏威夷旋转海豚和中层边界”惠特洛·W·L·奥博士生：Kelly J.Benoit-BirdSpner海豚在夏威夷的夜间以小鱼、虾和鱿鱼为食。它们的猎物白天在很深的地方，但每晚都在靠近水面和海岸线的地方迁徙。旋转的海豚跟随猎物的运动。它们随着猎物的迁徙向近岸和近海移动，潜入猎物最丰富的深处。旋转海豚还专门在高密度的猎物区域觅食，这些小区域的猎物比它们周围的动物更多。然而，其他对中上层捕食者的研究并没有表明这种类型的重叠与猎物。将使用扫描声纳同时收集旋转的海豚捕食者和猎物的数据，扫描声纳是一种设备，可以在三维中绘制捕食者和猎物的位置和丰度。用扫描声纳从船上跟踪觅食的海豚，并测量捕食区的密度和几何形状。这些特征的变化将被观察为海豚觅食，以观察它们如何影响猎物的行为。海豚可能使用回声定位，这是一种自然的声纳系统，来寻找它们的猎物。然而，这个系统是如何被野生动物用来觅食的，还没有研究。为了开始了解回声定位在觅食中的作用，回声定位点击率，即单个声纳信号，将在测量海豚与食物的距离时进行测量。如果旋转的海豚正在使用回声定位来寻找食物，那么随着海豚离猎物越来越近，点击的次数和它们的生产率应该会增加。这项工作将确定远洋捕食者是否可以与猎物在小范围内重叠，哪些行为允许这种情况发生，以及回声定位在海豚寻找食物中扮演什么角色。

"Fine-scale pelagic predator-prey interactions:Hawaiian spinner dolphins and the mesopelagic boundary"Whitlow W. L. AuDoctoral Student: Kelly J. Benoit-BirdSpinner dolphins in Hawaii feed at night on small fish, shrimp, and squid. Their prey is very deep during the day but migrates close to the surface and near the coastline every night. Spinner dolphins follow the movements of their prey. They move inshore and offshore along with their prey's migration and they dive to the depths at which their prey is most abundant. Spinner dolphins also forage specifically on high-density prey patches, small areas that have more prey than those around them do. Other studies of pelagic predators, however, have not shown this type of overlap with prey. Data will be collected on both spinner dolphin predators and their prey simultaneously using scanning sonar, a device that will allow the location and abundance of predator and prey to be plotted in three-dimensions. Foraging dolphins will be tracked from a boat with the scanning sonar and the density and geometry of prey patches will be measured. Changes in these characteristics will be observed as the dolphins forage to observe how they affect the behavior of their prey. Dolphins probably use echolocation, a natural sonar system, to find their prey. How this system is used by animals in the wild to forage has however, not been studied. To begin to understand echolocation's role in foraging, the rate of echolocation clicks, individual sonar signals, will be measured while measuring the distance of the dolphins from their food. If spinner dolphins are using echolocation to find their food, the number of clicks and their production rate should increase as dolphins get closer to their prey. This work will determine if pelagic predators can overlap with their prey at small scales, which behaviors allow this to happen, and what role echolocation plays in dolphin's search for food.