SEMINAR: Seminar

Blue whales in the Australian context

This talk will showcase the use of long term passive acoustic data sets in defining the habits and abundance of wide-ranging, oceanic great whales, notably the blue whale complex with an emphasis on pygmy blue whales.

The Centre for Marine Science and Technology has been running an Australia wide sea noise logging program since 2000. This work has been supported by Industry, Defence and Government in Australian waters and in collaboration with the Australian Antarctic Division, has included deployments in the Southern Ocean. The IMOS program will enable us to collect systematic sea noise data from southern Australia, the Perth Canyon and off the east coast into mid 2013. Male great whales vocalise profusely, emitting powerful, species specific calls designed to travel long distances. Signals from Antarctic blue whales and the pygmy blue whale sub species feature prominently in many Australian sea noise data sets. In the Perth Canyon the number of calling pygmy blue whales per unit time has been tracked since 2000, allowing comparison of visitation patterns within and between years. The Perth Canyon is a feeding stopover on the pygmy blue whale’s northern migratory leg, whales stay if there is food or move along if there is not. Along the Western Australian coast noise loggers have delineated a comparatively sharp pygmy blue whale southern migration from a northern terminus believed to be in Indonesia. Around the latitude of Exmouth pygmy blues whales pass south over October to December with a more protracted northerly migration over March to August. Pygmy and Antarctic blue whales form a prominent part of ocean noise in waters off southern Australia, with regular seasonal patterns, areas of localised abundance and wide ranges of detections. The noise loggers enable us to obtain counts of relative numbers of whales passing fixed points at a fine resolution. We are working on techniques to convert these relative numbers to absolute abundance of whales passing