Scott River health check reveals waters rich in native species

A health check of the Scott River and tributaries of the Lower Blackwood catchment has revealed a system rich in native fish and crayfish, including spawning grounds for native species such as the vulnerable Balston’s pygmy perch.

Scientists from the Department of Water and Environmental Regulation (DWER) have been conducting the health check as part of the Healthy Rivers program. 

The river health assessments collect data on a range of ecological aspects including fish, crayfish, macroinvertebrates, water quality, aquatic habitat and vegetation.

This recent assessment showed that the Scott River, Glenarty Creek, Twinems Bend and West Bay Creek were dominated by native freshwater fish and crayfish, with the majority of these species unique to south west Western Australia.

Lead scientist Bronwyn Rennie said 1300 native freshwater fish were counted at one site on the Scott River, with this area offering an important refuge and spawning ground for native fish including the rare Balston’s pygmy perch Nannatherina balstoni.

“It was exciting to find Balston’s pygmy perch in the Scott River, as this species is listed as vulnerable and facing a high risk of extinction in the wild,” Ms Rennie said.

“This and the fact that two Scott River sites showed no signs of exotic species, were very encouraging results of the survey work.”

Another exciting find was the Augusta burrowing crayfish (Engaewa similis). 

“These exquisite, violet-purple coloured native freshwater crayfish are quite rare due to alteration of their natural habitat,” Ms Rennie said.

“They grow to 5 cm in length, are known to live only between Margaret River and Lake Jasper, and create distinctive soil chimneys as they burrow into the water table.”

River health assessments help identify areas where on-ground work to protect and improve waterways should focus.

This work will be used to support Regional Estuaries Initiative (REI) work in the lower Blackwood catchment.