| Summary: | Progress Code: completed Purpose The Antarctic Blue Whale Project (ABWP; an initiative within the International Whaling Commission Southern Ocean Research Partnership - IWC SORP) has the primary aim of estimating circumpolar abundance of Antarctic blue whales (Balaenoptera musculus intermedia). Mark-recapture methods, using genetics and photo-ID, will form the foundation of future blue whale circumpolar abundance estimates produced by the ABWP, but the success of these methods require a high number of encounters with these animals. In the Southern Ocean, acoustic detection ranges of blue whales far outstrip visual sighting ranges, so real-time acoustic tracking can be used to increase the total number of whale sightings, thus making more efficient use of expensive ship time. Before undertaking an Antarctic blue whale research program that features acoustic tracking, instrumentation and methods specific to acoustic tracking of blue whales must be developed, and the capabilities and limitations of such an acoustic tracking system should be quantified. The Australian Antarctic Division undertook two voyages, both three weeks in length, in January and March, 2012, respectively. The surveys targeted the Bonney Upwelling, along the south-east coast of Australia, an area known to be a summer (Nov-May) feeding ground for pygmy blue whales; the surveys focussed on the area bounded by 141.0-143.0 degrees E and 38.0-39.5 degrees S. These voyages were undertaken in order to address the practicalities of 24-hour/day real-time acoustic tracking. Achieving these goals required characterising the capabilities of the acoustic tracking system, assessing the practicality and performance of different survey protocols, and integrating acoustic tracking with visual survey methods and mark-recapture methodologies. Of the six weeks allocated across both surveys, weather allowed for a total of 20 survey days (ten for each survey). The tracking system operated continuously during the voyages recording nearly 500 hours of audio, while ...
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