Cetacean stranding mechanism

Ralph James, Shane Chambers & Simon Woodings

Sound propagation in a coastal marine environment and implications for cetacean echolocation.


Certain Western Australian beaches appear to offer greater risk for cetacean mass strandings than others. A physical understanding of this can be gained from consideration of the various factors relating to sound propagation through bubbly water near gently sloping beaches. Consideration of the basic features of echolocation and cetacean navigation indicates the major processes that reduce the effectiveness of this sense.

The ability of Odontoceti (toothed whales or dolphins) to detect a shoreline should be considered in the light of known physiological and acoustical parameters. The dynamic range and frequency response of the cetacean's sonar sense is fundamentally limited by ambient ocean noise levels and attenuation processes. Weather dependent distributions of microbubbles in the water column are found to provide the dominant loss mechanism for cetacean sound in the coastal environment.


Whale strandings vs year


Unfolded geometry

Animations of echolocation

Be warned - these movies are about 700k each!

echo10.mov

echo4.mov

echo9.mov

echo13.mov


f vs bubble radius