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Supporting environmental impact assessment for offshore windmil farms

• Offshore windmils are the major candicate among the electric power sources for next decades. Reliable impact assessment is required for the smooth procedure of constructions and for the sustainable ocean environment.
  
  
• However, long term observation of aquatic animals and impact in the ocean is not easy task.
  
  
• Passive acoustic monitoring of dolphins and porpoises, key stone species in the ocean, will help efficient environmental assessment, which satisfy the requirement by central or regional regulations. We support not only the hardwares but also the operations and the data analysis as well.
  
  

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Abundance and distribution of dolphins and porpoises

• Line transect method has been used for the abundance estimation of cetaceans. Observers conduct visual survey from a moving ship cruised on the pre-fixed lines and count the number of surfaced cetceans.
  
  
• However, visual survey can not be conducted during nighttime, foggy or roughweather conditions. Visual observer likely to miss animals in the water.
  
  
• Acoustic line transect by receiving sonar sounds of dolphins and porpoises is helpful solution. Towing A-tag fixed behind the moving ship gives us the direction of a sound source (an animal). Feasibility of this method has been tested for finless porpoises in the Yangtze River, China first and widely used for the observation of echolocating odontocetes in marine and freshwater systems now.

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Acoustic biologging

• Biosonar behavior of dolphins and porpoises can be observed by the minuature version fo A-tag, which can be attached on the animal by a suction cup. Dolphins and porpoises are able to sense underwater objects using ultrasonic pulses just like a fish echosounders. A-tag records the sound source direction to separate own or other phonation as well as the received intensity of each click sound.
  
  
• The A-tag was designed robust enough to work on the swimming animal. It has sufficient pressure and water resistant ability. MMT has long experience to develop such compact and tough devices.
  
  
• Scientific papers using A-tag can be found HERE.

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