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).