Bunbury dolphins shown to be skilled seafood chefs
New findings by Murdoch University researchers have shown that local dolphins are the hottest seafood chefs in the south-west.
Dr Holly Raudino and Dr Kate Sprogis, two researchers from the Murdoch University Cetacean Research Unit, have recorded Indo-Pacific bottlenose dolphins off Bunbury going to elaborate lengths to prepare a tasty, tender calamari feast on giant cuttlefish.
The team has tracked the Bunbury dolphins since 2007, and has observed some very unusual feeding habits over this time.
"Dolphins often develop complex ways to find food that is unique to their habitat," said Dr Sprogis.
"However, consuming cuttlefish in the manner of the Bunbury dolphins has only been reported in two other places around the world."
The dolphins captured the cuttlefish and brought them up to the surface of the water to begin their culinary preparations.
Quickly nipping off the cuttlefish heads and tentacles, the dolphins squeeze the bodies in their teeth to squirt the ink out.
Turning their attention to the main body of the cuttlefish, the dolphins place it over their snouts and use the force of a tail-up dive under the water to keep the cuttlefish secured.
The dolphins then release the cuttlebones, which float back up to the surface, and the dolphins eat the remaining soft flesh.
"We have only observed this behaviour seasonally in the cooler months when the giant cuttlefish spawn and subsequently die," Dr Raudino said.
"Nobody has studied the cuttlefish so it is unknown how big the population is or if it is an important aggregation.
"In South Australia the effects of desalination have lowered the reproductive success of cuttlefish. This is a concern in Bunbury as the effects of the hypersaline discharge on the cuttlefish is unknown. The importance of cuttlefish to the dolphins' diet is also unknown."
"It was also very interesting to note that this elaborate food preparation was mainly restricted to adult females, which may mean that mothers are teaching their daughters. This is something we would have to explore further though."
The study, which is published in the Australian Journal of Zoology, is part of a long-term investigation into the population and behavioural ecology of Indo-Pacific bottlenose dolphins off the temperate waters of Bunbury, south-western Australia.
More information: H. C. Smith et al. Seasonal feeding on giant cuttlefish (Sepia apama) by Indo-Pacific bottlenose dolphins (Tursiops aduncus) in south-western Australia, Australian Journal of Zoology (2016). DOI: 10.1071/ZO15075
Journal information: Australian Journal of Zoology
Provided by Murdoch University