Songs in the Southern Ocean
20 July 2007
The Southern Ocean is an immense area to keep watch over for the presence of whales. Researching free ranging marine mammals is difficult because they travel huge distances, spend very little time at the surface, and are difficult to see in the often harsh Antarctic conditions
The good news is that even though we don’t often see whales, we can hear and record them.
Studying whales using acoustics, recording the sounds they make, is very efficient because whales use sound to communicate with each other and water is an incredible conductor of sound. Instruments used to record sound can work independently for a year or more. The research is entirely passive – the whales are unaware its taking place.
Whales make a wide range of sounds from short and simple, to being very complex and melodical – such as the humpback [MP3] and blue whale [MP3] songs. The blue whale sounds are below our hearing range so here they are played back at 8× speed so we can hear them. Identified by their differing songs, whale life histories are pieced together with acoustic recordings showing:
- relative abundance – the abundance of whales in one place compared with another
- distribution – where whales are located
- seasonality – what time of year they are present
Recording whale song
There are two different ways that we record whales
- Sonobuoys – these are deployed along vessel transects. They can survey large geographic regions for the presence and relative abundance of whales
- Bottom mounted acoustic recording devices. These allow continuous acoustic monitoring of targeted locations over long time frames
Support of this research is now enhanced with the establishment of the new Australian Marine Mammal Centre (AMMC).
Antarctic Magazine articles
- Tracking giants of the deep (Australian Antarctic Magazine 12: 31, 2007) – Satellite tracking of baleen whales will provide answers to basic questions about their life cycle, feeding habits and social interactions.
- New dietary facts from faeces (Australian Antarctic Magazine 11: 24–25, 2006) – DNA analysis of faeces is a non-invasive method for studying the diets of seals and penguins.
- Listening for whales (Australian Antarctic Magazine 11: 5, 2006) – Remote listening devices are helping scientists eaves drop on whales in the Southern Ocean.
- Sounds of the 'silent' world (Australian Antarctic Magazine 9: 14–15, 2005) – Remote acoustics is helping to monitor the presence of baleen whales in the Southern Ocean.