Why footage of dolphins ‘beaching’ is important
A RESEARCHER will dedicate time to learning wether highly risky 'beaching' behaviour from dolphins is being taught to juvenile dolphins.
Southern Cross University researcher Dr Daniele Cagnazzi will study footage of a pod of Australian humpback dolphins 'stranding' or 'beaching' themselves to see if the behaviour is being 'culturally transmitted' from mothers to calves.
Dr Cagnazzi, who studies the species in the Fitzroy River in Central Queensland by looking at population, genetics and toxicology data, first witnessed the behaviour 12 years ago (while driving over a bridge) during the daily boat surveys.
Now he has been able to dedicate a full week to studying the behaviour and documenting it using drone footage.
"This type of feeding is very risky, as dolphins run the risk of remaining stranded, however, since this behaviour is routinely repeated it must provide an important proportion of their daily feeding needs - dolphins must consume 4-6 per cent of their own body weight in fish each day.
"This feeding only occurs at low tide when the mud banks are exposed, therefore, habitat modification change, increasing flood frequency and sedimentation may affect the ability of dolphins to strand feed to provide their daily food needs. This is something we will continue to monitor."
He said they would use data collected over 13 years to identify individual dolphins and to see whether an adult and juvenile participating in the behaviour were related in any way and whether the behaviour was being 'taught'.
"The number of dolphins involved in a single episode varies from one to two while the rest of the group is busy in other activities and strand feeding can be full body or partial."
He said it was only in the Fitzroy River that the behaviour could be consistently seen as opposed to sporadic reports of it occurring in North Queensland and the Northern Territory.
He said the correct weather, feeding and water conditions were all critical to being able to witness the behaviour and properly document the event.
Dr Cagnazzi said dolphins around the world have shown different feeding strategies and until now strand feeding had been documented in very few locations internationally and primarily to bottlenose dolphins.