Kangaroo Island’s platypus population is showing good signs of recovery in the wake of the devastating 2019-2020 bushfires.

There was thought to be about 150 platypuses on Kangaroo Island before the fires, mostly living in waterholes in Rocky River and Breackneck River. 

The platypuses on Kangaroo Island are the descendants of a population introduced from Victoria and Tasmania in the 1920s. It was hoped the island would be a refuge for the species, which was already threatened by that time.  

Dr Ryan Baring of Flinders University and Dr Gilad Bino from the University of New South Wales travelled to the Rocky River area of the Flinders Chase National Park in late May to assess the platypus population and condition.

They spent a week setting traps and observing animals.

National Parks and Wildlife Services Kangaroo Island Conservation Ecologist Heiri Klein said the expedition was a resounding success, but the rocky terrain posed many challenges to the small research team.

“The sites where we thought the platypuses would be were quite isolated, so the team had to walk into most of the remote trapping locations on foot, whilst towing a boat loaded with all the equipment by hand,” Heiri said.

“Platypuses are most active at night, so the surveys also required wading out in cold water in the pitch black to check traps for eight nights in a row.

“After a trying start, the researchers successfully trapped two healthy juvenile females, two healthy juvenile males, and four mature platypus.

“The age of the juveniles mean they would have been born after the 2020 fires that affected the entire Rocky River catchment, which is great news for the recovering Kangaroo Island platypus population.”

Dr Gilad Bino from the University of New South Wales said despite the positive findings, the survey also revealed the impact to platypuses in some areas, with no platypus caught further upstream at the Platypus Waterholes or East Melrose Track.

“This was likely as a result of the dry conditions upstream which preceded the fires but also longer-lasting effects of the fires on the habitat and perhaps the platypuses,” Dr Bino said.

DNA samples taken from the platypuses will be analysed to provide an indication of the likely population size in the Rocky River system, but also possible genetic bottle necks that may affect the viability of the Kangaroo Island population.

The researchers are expected to return to Kangaroo Island in September to complete the survey sampling to better understand the extent of the platypuses’ recovery.

Platypuses are thought to be functionally extinct on mainland South Australia but a scoping study is currently underway to see if they could be reintroduced to the River Torrens/ Karrawarri Parri. 

Visitors can undertake a 4.7km Platypus Waterhole Walk within the Flinders Chase National Park.

Dawn and dusk are the best times to try and spot a platypus in the wild.