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Tuross River and the Spiny Cray

At the end of 2019, prolonged drought impacts and then widespread bushfire, followed by subsequent rainfall, saw some of Australia’s most precious and unique waterways destroyed.

OzFish and Landcare Australia have joined forces to help threatened species which suffered from the Black Summer fires thanks to the Landcare Australia Aquatic Wildlife Habitat Bushfire Program.

A collaborative approach

OzFish Eurobodalla Chapter with Eurobodalla Landcare and Eurobodalla Shire Council (ESC) have been collaborating to recover areas of Clayton’s Spiny Crayfish habitat degraded by bushfire in the Tuross River catchment.

Together, the groups have identified a property on the river and have undertaken three consecutive days of weed control; removing Tobacco bush, Winter senna, Turkey Rhubarb, Cape Ivy, Moth Vine and Honeysuckle.

Following this removal, 3.2 kilometres of stock-proof, electric fencing will be installed around the property allowing riparian areas to re-establish and new plantings to be protected.

Volunteers from OzFish and Landcare groups will plant approximately 2,500 native species of trees and shrubs to provide habitat for Claytons Spiny Crayfish, concurrently reinstating connectivity to adjacent vegetation for arboreal fauna and to stabilise the banks from future erosion.

What on earth is eDNA?

Environmental DNA (aka eDNA) is genetic material from an organism, like a plant or an animal, that can be found in the environment. Similar to us taking a shower, when a fish is in a waterway, it sheds cells,into the water as it goes about its day. These cells can be derived from things like mucus off its skin and excrement. By collecting and analysing water samples, we can detect the presence of certain species even if they might be hard to physically spot, like many of our native threatened fish. Confirming the presence of a species in the waterway helps us to protect their homes and in turn, protect the species.

Spiny Cray Cuties

Euastacus crayfish, known as the ‘spiny crays’ are endemic to the eastern states of Australia. Euastacus species are distinct from other species of crayfish in Australia as they have a clear row of spines on the lateral surface of their chelae or claws, making recognition relatively easy.

Claytons spiny crayfish (Euastacus claytoni) are an intermediate-sized spiny crayfish and inhabit the Tuross River and other tributaries of the Shoalhaven, Murrumbidgee, MacLaughlin and Snowy Rivers amongst others. They are found in larger streams and rivers, preferring permanent, cool, flowing water. Unfortunately, they are easily captured in fishing traps, and predation of juveniles by trout and platypus regularly occurs. However, they remain a very robust species that is less aggressive than most other spiny crayfish, spending much of their time within their burrow and are relatively resilient to habitat alteration, being found in streams through cattle grazing paddocks and pine forests.

Citizen Science to the Rescue

Unfortunately, the extent and severity of the Badja Forest Road bushfire that decimated the far-south coast of NSW likely significantly impacted this species, given their distribution in areas of burned areas. Furthermore, run-off from the steep catchment following the fires likely filled in burrows and reduced availability of prey for the Claytons Spiny Crayfish.

OzFish and its volunteers from the local OzFish Eurobodalla Chapter and Landcare will also be carrying out water quality, eDNA sampling and waterbug testing during the planting and education day to determine the species of fish in the system, monitor the population, and determine basic metrics indicating overall health of the waterway through citizen science.

The Landcare Australia Aquatic Wildlife Habitat Bushfire Program is funded by the Australian Government’s Wildlife and Habitat Bushfire Recovery program.