The mass stranding of whales can be disastrous for a particular pod of whales as well as greatly distressing for any human witnesses.

Recent events in the south-west of Western Australia have shown that the human response to such strandings involves a coordinated mobilisation attempt to rescue all or part of the beached animals.

Many theories have been proposed to account for such events, but none have been able to totally account for the varying types of whales stranding, the places such events occur and the times they strand.

Since strandings have been noted and reported since historical times, suggested causes based on recent human behaviour such as naval testing, toxic effluents or noise pollution are unable provide a complete explanation for each stranding event.

Since 1989 a small group of researchers within the School of Physics , University of Western Australia have looked into the available information on whale strandings with a goal to providing a scientifically sound explanation.

The researchers have identified four principle factors that combine to create conditions where a mass stranding can occur:

(1)   The presence of gently sloping sandy beaches.

(2)   Weather conditions – especially high winds and/or rain during or shortly prior to the stranding.

(3)   Lack of geographical knowledge on the part of the stranding pod.

(4)   The strong social support behaviour of whales and dolphins leading to the subsequent stranding of healthy animal attempting to aid a stranded animal.

Many of the beaches along Western Australia ’s coast constitute a potential hazard for particular whale species. Over 25 mass strandings have occurred during the last 50 years along W.A.’s coast involving the deaths of over 480 animals and the attempted rescue of over 1000 stranded individuals.

Previous investigators have acknowledged the importance of the factors listed above, but have been unable to draw all of the information into a coherent model to explain why stranding are particularly prevalent after storm events, even though the weather conditions at the time of stranding may appear very good.

The recent results highlight the important roles of multiple reflections from gently sloping sandy beaches and tiny (micro sized) bubbles caused by stormy weather in any mass stranding event. Microbubbles can reside in the water for many days after a storm has passed and can effectively absorb whale signals.

This project will involve the analysis and identification of individual animals using some exclusive footage provided by a local documentary maker, Leighton De Barros. Identification will be based on individual fin and scar characterisation. This will be achieved by digitally comparing photographs taken of a pod of pilot whales observed at Koombana Bay, Bunbury 10 days prior to a mass stranding of pilot whales at Busselton in April last year. This project may also involve characterisation of the slope and topography of the underwater environment of Koombana Bay .

The project will require the application of computational strategies well known in object identification software (such as face recognition). The data set consists of about 100 high resolution photograph and 3 hours of video footage in mini DV format.

Students will acquire knowledge of digital image and video editing and manipulation along with basic computational mathematical techniques used in auto object identification.

It is anticipated that this project will begin in the first few weeks of Semester 1, 2005. Results supplied by the students will have a significant role in the ongoing whale stranding research and will be featured in a forthcoming documentary to be shown on ABC/BBC television networks. Students will be most likely be filmed at some stage performing research.

For more information on Bioacoustics Research at UWA refer to the projects webpage:

www.biophysics.uwa.edu.au/Bioacoustics

For more information on the student project offered please contact::

Ralph James  -  ralph@physics.uwa.edu.au

Shane Chambers  -   chambers@cyllene.uwa.edu.au