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

动物携带的视频系统的最新发展促进了对韦德尔海豹(Leptonychotes Wedellii)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，可以连接到自由活动的海洋哺乳动物上，以观察它们的水下行为，跟踪它们的三维运动，并同时记录关于它们环境的数据。目前的努力将建立在这一成功的基础上，并将技术推进到下一个水平。将重新设计视频/数据记录器，包括以下新功能：数字视频记录长达30小时，全球定位系统(GPS)用于在地表进行地理定位，延长数据记录长达14天，尺寸缩小50%。开发包括高级数字视频/数据录像机和操作软件的规格。新的视频/数据记录器将由加尔维斯顿的德克萨斯A&M大学和加利福尼亚州圣地亚哥的双鱼设计公司联合设计和制造。该系统将由两部分组成。第一个将是一个小型铝制外壳，用于微控制器和传感器，用于压力、游泳速度、指南针方位、环境温度、环境溶解氧、环境光水平、倾斜度、俯仰和侧滚。使用31 GB或更大的微型硬盘驱动器存储压缩的数字视频和音频将允许与以前的设计相比相当大的尺寸减小，同时保持完全的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位或更高分辨率的模数转换器。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提供动力。第二个外壳将包含以近红外发光二极管(LED)为光源的微型摄像机。这款相机将是一款低光敏度的黑白相机。这款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(海洋哺乳动物和鱼类看不到近红外光)。这种新一代的视频/数据记录器最初将被用作目前对南极洲自由活动的韦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的一般觅食策略、搜索行为、搜索机制、游泳模式和觅食效率的研究。新仪器将提高进行这些调查的能力，提供高质量的数字视频记录，增强我们跟踪动物在水面(使用GPS)和水下(使用三维跟踪)移动的能力，并缩小尺寸以减少水动力阻力。除了对海洋哺乳动物的研究外，视频/数据记录器还广泛适用于各种潜水平台和人类潜水员。录像机/数据记录器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.