Development of monitoring systems for studying ecology and behavior of bottlenose dolphins-taking aerial pictures of schools using a captive balloon system and recording underwater vocalizations using a sonobuoy system-

印度-太平洋宽吻海豚一年后才在日本九州的阿马库萨沿海水域被发现。为了研究海豚的生态和行为，开发了监测系统；一个用于拍摄学校航拍的圈养气球系统和一个用于记录学校水下发声的声纳浮标系统。该气球系统由一个充满氦气的圈养气球(直径2.5米)、悬挂在气球上的视频子系统(2.1公斤)和船上的控制子系统组成。以下信息来自一所学校的图像1；学校成员的空中行为、浮出水面的个体数量的时间变化、学校的形态和个体的空间分布。当用长焦镜头拍摄学校的一小部分时，母婴对与其他人是不同的。母犊对与所有个体的比例的季节性变化表明，春季到秋季是主要的分娩季节。该系统适用于外层鲸类。除了使用这两种系统进行调查外，还尝试了用船上的水听器直接记录发声，从陆地上用经纬仪跟踪，行为观察，以及用于个体识别的摄影调查。发声录音显示，海豚有时会在前方几米或200米处进行搜索。经纬仪跟踪调查表明，白天沿海岸有规律的运动模式。行为观察表明，在一天中的炎热时期，海豚会在有限的区域休息。个人身份调查估计人口规模接近200人，死亡率为每年3.4%。

Indo-Pacific bottlenose dolphins are found thoughout a year in the coastal waters of Amakusa, Kyushu, Japan. To study ecology and behavior of the dolphins, monitoring systems have been developed ; a captive balloon system for taking aerial pictures of schools and a sonobuoy system for recording underwater vocalizations from schools.The balloon system consists of a captive balloon(2.5 m in diameter)filled with the helium gas, a video sub-system(2.1 kg)suspended from the balloon and a control sub-system on a boat. The following information was obtained from images of a schoo1 ; aerial behavior of the school members, temporal changes in number of surfacing individuals, configuration of the school and spatial distribution of individuals. Mother-calf pairs were distinguishable from others when a small portion of the school was taken using a telephoto lens. Seasonal changes in ratios of mothercalf pairs to all the individuals suggest the main parturition season of spring to autumn. This system is applicable to outer cetaceans.Tother with surveys using the two systems, direct recordings of vocalizations by a hydrophon from a boat, theodolite tracking from land, behavior observations, and photographic surveys for individual identification were attempted. Vocalization recordings show that the dolphins searched sometimes a few meters ahead or 200 m ahead. Theodolite tracking surveys clarify a regular movement pattrn along the shore in the daytime. Behavior observations suggest that the dolphins take a rest in a limited areas during the heat of the day. Individual identification surveys give estimetes of population size of almost 200 individuals and mortality rate of 3.4% per year.