Native fish numbers a positive sign for waterways
A recent survey of local catchment areas has shown reasonable numbers of native fish present – which is good news for the environment.
Natural Resources Northern and Yorke Water Officer Jennifer Munro says the findings show that the Broughton and Wakefield catchments are in fairly good condition.
“The majority of the fish we found in high numbers were introduced fish such as mosquito fish and wild goldfish, but there were also reasonable numbers of native fish such as galaxias and blue-spot goby,” she says.
“We also caught quite a lot of yabbies and shrimps at most of the sites and some long and short necked turtles as well.”
One exception was the northern part of the Rocky River – part of the Broughton catchment – that was affected by the Bangor bushfires in January and February this year.
“In the northern end of the Rocky River, we found yabbies and tadpoles but no fish in the first three sites, where the water was still black from the fire sediment,” Ms Munro says.
“However, as we headed downstream we started catching fish.
“The positive news is that with the wet winter we’ve had, the Rocky River has had an extended continuous flow of water and we’re hoping that in the next survey we’ll see evidence that there has been enough flow to flush that area and that fish and other aquatic species have been able to return.”
The presence of juvenile galaxias, a diadromous fish species, in the Broughton catchment was also an interesting find relating to salt levels.
“Diadromous fish migrate between salt and fresh water and represent only one per cent of the world’s fish,” Ms Munro says.
“We found juveniles of this species, so it’s obviously reproducing successfully. This suggests either the catchment is experiencing some level of connectivity to the sea, or more likely, there’s enough variation in the saltiness within the catchment to enable them to grow through the fresh water and salt water phases of their lifecycle.”
Coordinated by David Schmarr of SARDI, the native fish surveys were part of the Federally-funded Four Catchments Project – launched in 2012 to encourage landholders, community groups and volunteers to take an active role in looking after their catchments.
The project includes a range of on-ground works including revegetation, weed management and fencing.
For more information contact Natural Resources Centre Northern and Yorke on 8841 3444.