Design / Develop / Analyze / Consult with MMT __________________ MMTがお手伝いする、設計・開発・解析・コンサルティング _____________________ Contact / ご連絡はこちら

Stationary type A-tag

• This type of A-tag can be fixed at a focal area and observes dolphins and phonating crustaceans around it. It runs 30 days continuously with two off-the-shelf UM1 batteries. Minimum number of presented animals can be observed without any human effort. Stationary type A-tag has been used for the environmental impact assessment of offshore windmills.
  
  
• Since A-tag has two hydrophones, sound source bearing angles of sounds can be calculated and recorded. This procedure is automatic. Independent sound source is the proxy of number of animals. Change of sound source angle show the underwater behavior. Unlike full band recorders, A-tag is the pulse event recorder that makes the data visualization and analysis easier.
  
  
• Type I is for the deployment on a rope with a buoy and an anchor. Type T is for the deployment firmly on the seabed or waterbreaks.
  
  

  ---

  ---

Towing type A-tag

• This type of A-tag is to count the phonating animals in a focal area. For the acoustic line transect, A-tag will be simply towed from a ship, instead of great effort by professional visual observers. It is small enough to be fixed on a rope behibd of the ship. Because dolphins and porpoises were observed to produce biosonar sounds quite frequently, they can be detected even in the water. This method is especially effective for coastal small odontocetes such as finless porpoises, harbor porpoises, Irrawaddy dolphins, Chinese white dolphins and river dolphin species in turbid waters.
  
  
• Towing can be done by a small boat. It has 30 hours life time, which is sufficient for the boat survey for each day.
  
  
• For the practical operation of towing, see this page

  ---

  ---

Tagging type A-tag

• This type of A-tag is for acoustic biologging, to observe the biosonar behavior of dolphins and porpoises. A-tag can be attached on the animal by a suction cup. Dolphins and porpoises are able to sense underwater using ultrasonic pulses just like a fish echosounders. A-tag record the sound source direction to separate own or other phonation as well as the received intensity of each click sound.
  
  
• Acoustic biologging need several tips by an expert. Contact us for details unless you have experiences for biologging study.
  
  
  
•