Development of a Digital Video/Data Recorder for Monitoring Behavior and Multi-Dimensional Movements of Marine Mammals at Sea

动物传播视频系统的最新发展促进了威德尔海豹（Leptonychotes weddellii）对寒冷黑暗的南极快冰环境的行为和能量适应的研究。PI开发了一种小型模拟视频/数据记录器，可以连接到自由放养的海洋哺乳动物身上，观察它们的水下行为，跟踪它们的三维运动，同时记录它们周围环境的数据。目前的努力将建立在这一成功的基础上，并将技术提升到一个新的水平。视频/数据记录仪将被重新设计，包括以下新功能：长达30小时的数字视频记录、用于地面地理定位的全球定位系统（GPS）、长达14天的数据记录，以及尺寸缩小50%。开发包括先进的数字视频/数据记录器和操作软件的规格。新的视频/数据记录仪将由加尔维斯顿的德克萨斯农工大学和双鱼设计公司（San Diego， CA）共同设计和制造。该系统将由两部分组成。第一个将是一个小型铝外壳，用于微控制器和压力、游泳速度、指南针方位、环境温度、环境溶解氧、环境光照水平、倾斜、俯角和滚转传感器。使用31千兆字节或更大的迷你硬盘驱动器来存储压缩的数字视频和音频，将允许从以前的设计中大大减小尺寸，同时保留完全可编程性，并将记录持续时间增加到约30小时。微控制器将具有至少8个12位分辨率或更高的模数转换器。这个外壳还将包含锂离子电池，为微控制器、指南针、传感器和GPS供电。第二个外壳将包含以近红外发光二极管（LED）作为光源的微型摄像机。相机将是一个低感光，黑白相机。这台高分辨率相机对可见光和近红外波长的光很敏感。近红外LED光源设计用于在完全黑暗的情况下成像，而不会干扰动物的行为（近红外光对海洋哺乳动物和鱼类是不可见的）。这种新一代的视频/数据记录仪最初将被用作目前对南极洲自由放养的威德尔海豹觅食行为研究的一部分，并将对海洋动物的活动产生新的见解。这包括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、游动方式和觅食效率的研究。新仪器将通过提供高质量的数字视频记录，提高我们在水面（使用GPS）和水下（使用三维跟踪）跟踪动物运动的能力，以及缩小尺寸以减少水动力阻力，从而提高进行这些调查的能力。除了海洋哺乳动物的研究外，视频/数据记录仪还广泛适用于各种潜水平台和人类潜水员。录象/数据记录仪将有助于开发新的海底技术和仪器，以便更好地了解和保护海洋生物及其栖息地。

Research on the behavioral and energetic adaptations of Weddell seals (Leptonychotes weddellii ) to the cold dark Antarctic fast-ice environment have been facilitated by recent developments in animal-borne video systems. The PI has developed a small, analog video/data recorder that can be attached to free-ranging marine mammals to observe their underwater behavior, track their three-dimensional movements, and simultaneously record data on their environment. The current effort will build on this success and advance the technology to the next level. The video/data recorders will be redesigned include the following new features: digital video recording for up to 30 h, a Global Positioning System (GPS) for geolocation at the surface, extended data recording for up to 14 days, and a 50% reduction in size. Development includes specifications for an advanced digital video/data recorder and operating software. The new video/data recorder will be jointly designed and fabricated by Texas A&M University at Galveston and Pisces Design (San Diego, CA). The system will consist of two parts. The first will be a small aluminum housing for the microcontroller and sensors for pressure, swim speed, compass bearing, ambient temperature, ambient dissolved oxygen, ambient light level, tilt, pitch and roll. The use of a 31 gigabyte or larger mini-hard drive for storing compressed, digital video and audio will allow a considerable size reduction from previous designs while retaining full programmability and increasing the recording duration to ca. 30 h. The microcontroller will have at least 8 analog-to-digital converters at 12-bit resolution or greater. This housing will also contain lithium ion batteries that will power the micro-controller, compass, sensors and GPS. The second housing will contain the miniature video camera with near-infrared light emitting diodes (LED) as a light source. The camera will be a low light sensitive, black and white camera. This high-resolution camera is sensitive to visible and near-infrared wavelengths of light. The near-infrared LED light source is designed for imaging in total darkness without disturbing the animal's behavior (near-infrared light is invisible to marine mammals and fishes). This new generation of video/data recorder will be used initially as part of current studies of the foraging behavior of free-ranging Weddell seals in Antarctica and will yield new insights into the activities of animals at sea. This includes the study of general foraging strategies, searching behavior, searching mechanics, modes of swimming, and foraging efficiency for different environmental conditions and prey type. The new instruments will advance the ability to conduct these investigations byproviding high quality digital video recordings, enhancing our ability to track the movements of animals at the surface (with GPS) and while submerged (with three- dimensional tracking), and reducing the size to decrease hydrodynamic drag. In addition to the study of marine mammals, the video/data recorder has broad applicability to a variety of submersible platforms and human divers. The video/data recorder will contribute to the development of new undersea technology and instrumentation that can be used to better understand and protect marine organisms and their habitats.