2023_programme: Current real-time underwater acoustic monitoring systems in Japanese water

• Session: 12. Real-time underwater acoustic sensing and imaging systems: Advances- capabilities and results
  Organiser(s): Purnima Ratilal-Makris and Alessandra Tesei
• Lecture: Current real-time underwater acoustic monitoring systems in Japanese water [invited]
  Paper ID: 1972
  Author(s): Akamatsu Tomonari
  Presenter: Akamatsu Tomonari
  Abstract: Japan is located at the edge of the Pacific rim and has suffered severe earthquake strikes many times. To monitor seismic events, submarine cables have been installed in the Japanese Exclusive Economic Zone. The Kushio-Tokachi cable off Hokkaido, the norther big island of Japan, was deployed in 1999. S-net is the newly installed 5500 km submarine cable in operation since 2016, which covers the eastern side of Japan along the Pacific ocean, from off Hokkaido, Aomori, Sanriku and Boso peninsula, close to Tokyo. The installation of DONET1 (Dense Oceanfloor Network System for Earthquakes and Tsunamis) observational equipment on 20 stations was completed in 2011 in the offshore of west of Japan. These real-time passive acoustic monitoring systems were partially applied for the observation of baleen whales. Low frequency calls of fin whales have been detected mostly in winter time by S-net. Many fin whale calls were observed in the waters off Kushiro in the northern part of Japan. The results obtained by the acoustic monitoring were consistent with the previous visual observation of fin whales in Japan. A scientific submarine cable in Sagami Bay, 100 km west of Tokyo, revealed frequent encounters of sperm whales year around during 1994-2012 period. In the Ogasawara and Okinawa archipelagos, known as breeding grounds of humpback whales, songs were recorded using stationed or boat-based recordings.
• Corresponding author: Dr Tomonari Akamatsu
  Affiliation: Ocean Policy Research Institute, the Sasakawa Peace Foundation
  Country: Japan
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