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

“精细尺度的远洋捕食者-猎物相互作用：夏威夷旋流海豚和中远洋边界”Whitlow W. L. audr . Student: Kelly J. benoat - bird夏威夷旋流海豚在夜间以小鱼、虾和鱿鱼为食。它们的猎物白天在很深的地方，但每晚都会靠近海面和海岸线。飞旋海豚跟随猎物的动作。它们随着猎物的迁徙而向近岸和近海移动，它们潜入猎物最丰富的深处。飞旋海豚还专门在高密度的猎物斑块上觅食，这是一个比周围猎物更多的小区域。然而，其他关于远洋捕食者的研究并没有显示出这种与猎物的重叠。研究人员将利用扫描声纳同时收集飞旋海豚捕食者和猎物的数据，这种设备可以在三维空间中绘制出捕食者和猎物的位置和数量。用扫描声纳从船上跟踪觅食的海豚，并测量猎物斑块的密度和几何形状。这些特征的变化将在海豚觅食时被观察到，以观察它们如何影响猎物的行为。海豚可能使用回声定位，一种天然的声纳系统，来寻找猎物。然而，野生动物是如何利用这个系统来觅食的还没有被研究过。为了开始了解回声定位在觅食中的作用，在测量海豚与食物的距离时，将测量回声定位的咔哒声，单个声纳信号的速率。如果飞旋海豚使用回声定位来寻找食物，那么随着海豚离猎物越来越近，它们的点击次数和产出率应该会增加。这项工作将确定远洋捕食者是否可以在小范围内与猎物重叠，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.