Development of AUV for Whale following

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There are few studies on the behavior of whales in underwater. Conventional whale observation from ships gives us only the knowledge of their behavior on ocean surface. Recently new methods using satellite system and suction-cup-TDR tag system have been developed. Satellite system is effective for tracking whales on surface, but this system can not collect any data of whales in underwater. On the other hand, suction-cup TDR tag is effective for collecting data of whales not only on surface but in underwater, however it must be physically attached to a whale by researcher. The other problem is that tag is sometimes lost after it was apart from a whale. Consequently whale's behavior in underwater remains still uncertain to us, thus establishment of a new method which can be utilized for observing whale's behavior on surface and in underwater is expected.In this research, we proposed new whales observation system using AUV(Autonomous Underwater Vehicle) as an underwater platform. The resu … More lts of several sea trials show that the realized system works effectively.Most whales have particular sounds called vocalizations or clicks. Male humpback whales sing songs composed by complicated phrases. Sperm whales are known that they emit loud impulsive broadband sounds called clicks during their diving to a deep water. We analyzed their acoustic data using signal processing techniques and develop new compact acoustic system based on passive sonar for implementing to AUV. Using this system, AUV can get direction and depth information of each whales in underwater to classify and follow them in sub-real time.For the purpose of observing sperm whale's diving behavior, we did sea trials in 2002 and 2003 off Ogasawara Islands and improved the system. In September 2004, we finally could deploy AUV and collect some data with this system. The result of data analysis indicates this system is suitable for sperm whale following using AUV.For the purpose of observing humpback whales behavior, we collected sound data and established new sound model. The result of data sampling test indicates this model is appropriate to be used for classification of humpback whales. Next, we rebuild this model to more compact device to implement to AUV and track humpback whales using AUV.Based on this research, a river dolphin observation project using acoustic system has been started.For future works, we would like to propose carrying out sustainable whale observations using this system off Ogasawara Islands and off Okinawa Islands. Less