Do you have turtles in your dams and creeks? Are you aware of the critical role they play in regulating water quality, an important consideration for anyone with stock animals?
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November is Turtle Month and is when we're most likely to see turtles emerge from the water to nest.
Freshwater turtles can be found in most water bodies in our region, including golf course ponds, farm dams, lagoons, rivers and even irrigation channels.
The turtle's role as a scavenger is what makes it responsible for helping to maintain water quality in freshwater ecosystems.
Turtle scavenging can remove fish carcasses from the water five times faster than natural decomposition, dramatically improving water quality.
The Murray region is home to three different turtle species. The broad-shelled turtle (Chelodina expansa), the eastern long-necked/ snake-necked turtle (Chelodina longicollis), and the Murray/ Macquarie turtle (Emydura macquarii ssp. macquarii).
All three can live up to 50 years. Unfortunately, research has shown a 60 - 90 per cent decline in turtle numbers across the Murray-Darling Basin, primarily due to predation by foxes, which can destroy up to 95 per cent of turtle nests at a site. Turtles are also often victims of roadkills, especially this time of year when the long-necked turtle and the Murray turtle are nesting and moving about following rain.
The species
The broad-shelled turtle is the largest freshwater turtle in Australia, with a shell/carapace measuring up to 48cm long.
The broad-shelled turtle is rarely encountered as it is submerged in deep, turbid water most of the time. It is a specialised carnivore, preying on crayfish and small fish.
The long-necked turtle is an opportunistic omnivore that feeds on fish carrion and aquatic insects.
It is the region's most widespread and commonly encountered species and can be highly abundant in farm dams and irrigation channels.
The Murray turtle is also a generalist omnivore, although much of its diet includes a high proportion of rotting vegetation and algae.
The neck of the Murray turtle is much shorter than the length of its shell, and it often has a yellow stripe extending from its eye/mouth to its neck.
It is frequently encountered basking on emergent logs in large lakes and sewerage treatment ponds.
Nesting
Turtles usually nest within 100 metres of their water source but have been known to nest up to a kilometre from home (depending on the species), usually on a bit of raised, open, soft ground.
After digging holes up to 30cm deep, they can lay up to 30 eggs at a time.
The eastern long-necked / snake-necked turtle and the Murray River short-necked turtle both nest in the late spring, with an incubation period of around 120-150 days.
In contrast, the broad-shelled turtle lays eggs in autumn, which can take up to 12 months to hatch.
We can help turtles survive by:
- Reporting turtle and nest sightings to the TurtleSAT app or website.
- Taking care when driving near water bodies, especially after rain, and removing turtles from the road.
- Protecting known turtle nesting sites from foxes.