Dolphins could be exploiting the generosity of Queensland's recreational fishers and teaching each other how to beg for food.
University of Queensland researchers studying the social structure of Moreton Bay bottlenose dolphins found a cluster would patrol boats and wait for them to illegally toss discarded bait.
“Fishing is popular in the bay and it seems some dolphins have learnt to exploit it," Dr Leonie Huijser said.
Begging behaviour can be dangerous for dolphins and there are concerns the trait could spread among populations.
“Dolphins learn behaviour from their peers,” she said.
“If these 'beggar' dolphins start to associate with ‘non-beggar’ dolphins, the behaviour may spread rapidly, making it a population-wide problem.”
Signs of begging are not restricted to Moreton Bay, with sightings noticed nearby off Bribie and North Stradbroke islands.
Dr Huijser noted some dolphins approached boats with evidence of wounds and injuries caused by propellers and fishing line entanglements.
“During one of my first fieldwork days near North Stradbroke Island, a dolphin surfaced next to our boat but disappeared once it realised we weren’t going to feed it.
“Its fin had been badly mangled previously, indicating it may have been caught up in a line.”
Supervising professor Michael Noad said the findings show how adaptable bottlenose dolphins are but not all of their adaptations are positive.
He believes begging is an example of an adaptive strategy that may have short-term gain but long-term risks.
“Dolphins risk becoming reliant on donated fish, which is like junk food to them - quick and easy but unhealthy," he said.
“It may lead to food poisoning or nutritional imbalances."
Prof Noad said Dr Huijser’s findings should be used by wildlife rangers to increase awareness through a public education program around the potential negative effects of dolphin feeding."
