Butt-breathing turtle hit by Qld flood

Queensland's unique-looking Mary River turtle could be an unlikely victim of recent floods.
Queensland's unique-looking Mary River turtle could be an unlikely victim of recent floods.

An endangered bum-breathing turtle with punky green "hair" has some tough years ahead after a major flood in the Queensland river it calls home.

Turtle conservationist Col Limpus says nests of Mary River Turtle eggs have almost certainly been lost after ex-cyclone Seth dumped a phenomenal amount of rain over the catchment in recent days.

Nests of the rarer, critically endangered white-throated snapping turtle are also likely to have been damaged or destroyed after the Mary River reached a major flood level of 9.96 metres on Sunday.

That's not the end of the bad news, says Dr Limpus, who's also the chief scientist for wildlife and threatened species in Queensland's environment department.

"We have had an egg loss. The flooding, it's a very elevated level and any eggs that haven't hatched will have either been washed away or drowned. There is, however, a much greater problem."

The grinding, gouging and stripping effects of a major flood will mean a food shortage will pose multiple problems, including lower breeding rates in years to come, Dr Limpus says.

"If we take the bubs - the young turtles - they feed primarily on snails and insects and things like that in the shallows.

"When you have a major flood all of your gravel and sand and everything is being rattled around. Surfaces are sandblasted with sediment and we lose the food resource that should be there normally."

That doesn't bode well for this season's hatchlings, which only began to emerge last month, or for adults who rely on aquatic plants that will have been stripped away.

Dr Limpus says resources have been too scant to look at what past floods have done to the Mary River's turtle food stocks. But work done in the adjacent Burnett River, which is also home to the white-throated snapping turtle, paints a pretty clear picture.

"Following the highest flood we've ever recorded for the Burnett, in January of 2013, the plant life that would be growing in the bed of the river basically took several years to recover," Dr Limpus says.

"The consequence of that, of course, is that the capacity of the animals to continue to grow is compromised and we see adult turtles not coming into breeding conditions."

The chief scientist laments the challenges humans have thrown at species like the Mary River Turtle.

Known for the hair-like shocks of algae that grow on its head and shell, the species is still feeling the effects of the penny turtle trade.

In the 1960s and 1970s penny turtles were sold as pets in their thousands. Named because new hatchlings were about the size of an old penny, they were a hit with the kids of the day.

Vast numbers of them were actually Mary River Turtle hatchlings, along with other freshwater species.

"There was a businessman in Maryborough who found that he could go out to the mass nesting area for the Mary River Turtle ... and gather tens of thousands of eggs which he could hatch and sell into the pet trade," Dr Limpus says.

"That trade resulted in a massive, excessive egg harvest and it wasn't until 1974 that the Queensland government declared the turtles a protected species and the trade ceased."

In the 1960s, introduced foxes also began to significantly prey on turtle nests in Queensland, and they remain a major predator of both marine and fresh water turtles.

Last year, researchers inspected about 150 white-throated snapping turtle nests along one stretch of the Mary River and found over 90 per cent of them had been destroyed by foxes, Dr Limpus says.

"We also lose some to pigs and to dogs, and we've got native predators that have always been there like goannas. But it's the introduced predators that are extremely challenging to manage."

Groups such as the Tiaro and District Landcare Group have been working hard since the mid-1990s to protect nests of Mary River Turtle eggs, regularly putting them into what Dr Limpus calls "protective custody".

Protective barriers are placed over the nests to stop predators digging into the eggs. Predator cages that can be buried into the ground have also proven successful.

"You can open up the top, step in, put your eggs into artificial nests inside the cage, and close it up. The mesh size keeps predators out and allows hatchlings to escape when they emerge."

Changing weather patterns, of the type scientists blame on global warming, are creating additional challenges.

In December, the Burnett River saw an unseasonably early flood so high that water inundated some of the predator cages.

"We had a panic job on to get the eggs out. One of them had flood water running through as we were rescuing the eggs."

They were moved to a temporary site and remarkably some of the eggs have hatched, albeit at a reduced rate.

"The early season flooding was so atypical. We weren't anticipating it. Normally the eggs are all hatched and gone before you get your big floods coming through."

Dr Limpus says as climate change affects ramp up, community involvement to save endangered turtles will be crucial.

"It's a real challenge trying to look after these species when we have to be intervening. They have survived floods and droughts and all that sort of thing in the past.

"But we have changed the environment so much with the feral predators we've introduced, and the climate change issues, that we are now so challenged to keep these species in functional populations.

"We really need local communities to want to look after their area, like Tiaro has. They've done a marvellous job.

"It's an impossible task for government to look after every kilometre of river."

Australian Associated Press