13 March 2018
A post mortem recently carried out on a dolphin calf, found dead in the Port River in early January, suggests it died as a result of blunt trauma.
The bottlenose dolphin calf, named Holly by those who tracked his journey from birth, was born in the Adelaide Dolphin Sanctuary just before Christmas to mother Ripple. He appeared to be in good health but was found dead on 2 January near Port Adelaide’s M Berth, which is within the Adelaide Dolphin Sanctuary.
Globally recognised Senior Researcher of Mammals at the South Australia Museum, Dr Cath Kemper, led the necropsy on 6 February at the Museum’s purpose built collection and necropsy facility.
“Our examination showed Holly was a healthy little dolphin with no apparent signs of disease,” Dr Kemper said.
“However, he had severe, deep haemorrhaging on the head and chest which would have been caused by strong impact,” she said.
The South Australian Museum has been monitoring dolphin deaths in the Adelaide region for 30 years, as part of a program supported by the Adelaide and Mount Lofty Natural Resources Management Board.
Of 35 known dolphin fatalities in the last 13 years, 17 of these deaths have been the result of blunt trauma.
Lisien Loan, Manager, Parks and Sustainable Landscapes with Natural Resources Adelaide & Mt Lofty Ranges said young dolphins were very vulnerable during their first few months, and particularly in their first few weeks when they were learning to swim.
“Calves such as Holly can often appear quite uncoordinated as they learn to time their breathing at the surface. Adding to that, they can’t swim very fast and are vulnerable in shallow water because they can’t dive deeply to escape hazards such as boats,“ she said.
“Speed limits, varying from four to seven knots, apply within the Adelaide Dolphin Sanctuary and are posted at boat ramps and on pylons in the protected area.
“In addition, jet-skis must not move closer than 300 metres to a dolphin. Other craft must not move closer than 50 metres to a dolphin or closer than 150 metres to a dolphin calf.
“These rules are in place to protect Adelaide’s dolphins, and boat users are expected to observe them and take extra care during calving season.
Ms Loan said the success of the Adelaide Dolphin Sanctuary had demonstrated that humans and wildlife can live in close proximity.
“In general this works well, with many initiatives in the area improving the habitat for dolphins and other wildlife.
To find out more about the Adelaide Dolphin Sanctuary and how you can help protect the resident dolphins visit: