Fruitful fish-friendly flows
Some surprising underwater discoveries have highlighted just how healthy stretches of Gunbower Creek are.
Gunbower Creek has been the benefactor of water for the environment since 2013. Since then, minimum flows have occurred over winter and fluctuations in creek height are as ‘smooth’ as possible.
These flows have been targeted at providing better conditions for native fish to breed, feed, and survive.
And recent findings continue to show the program is having impressive results.
“As part of the Native Fish Recovery Plan, we’re working with Goulburn-Murray Water to build fishways at the Cohuna and Koondrook weirs,” North Central Catchment Management Authority (CMA) Program Delivery Executive Manager Rachel Murphy said.
“As part of those works, coffer dams have been built to keep the water out of areas under construction, and the creek levels have been lowered.
“We spent time salvaging and relocating any fish we could find so they didn’t get trapped. And what we found surprised us.
”As well as thousands of small native fish, about 100 Threatened Murray-Darling rainbowfish were caught, as were about 50 Murray cod of different sizes.
“But the big find was 28 trout cod immediately below Koondrook and Cohuna regulators, a fish that was facing extinction in the late 1980s and is still Critically Endangered,” Ms Murphy said.
“We have rarely encountered them in Gunbower Creek and we only have a few records in years of monitoring.
“And the fact there were a lot of smaller trout cod indicates to us they are likely breeding in Gunbower Creek, which is great news.
“And the other good news was around Murray cod and carp. Finding different sized Murray cod means our fish-friendly flows are making a difference to their breeding cycles and supporting both naturally bred and stocked fish to survive and grow in Gunbower Creek.
“Fish ecologists have also advised us that the high numbers of Murray cod in this part of the creek are likely to be supressing carp numbers, so to only find about 10 carp at the Cohuna site was a welcomed sign.”
Ms Murphy said the discovery of the trout cod showed how important the new fishways will be.
“Just like Murray cod, silver perch and golden perch, trout cod need to move to thrive,” she said.
“And giving them the opportunity to do that in the Gunbower Creek, and allowing them to move freely in and out of the Murray, will make a big difference.”
The project is a partnership between Goulburn-Murray Water (GMW) and the North Central Catchment Management Authority (NCCMA), who will oversee construction by Bendigo-based company S&R Engineering and Construction.
The fishway projects are joint-funded by the Victorian Environmental Water Holder (VEWH) through the sale of water for environment, GMW, and the Victorian Government’s $2.7 billion Building Works package to support projects and jobs across the state as part of the coronavirus (COVID-19) economic recovery.
The flows are authorised by Victorian Environmental Water Holder in line with its Seasonal Watering Plan 2020-21, which is available for download from www.vewh.vic.gov.au, with regular watering updates posted on the North Central CMA website www.nccma.vic.gov.au.
Fish monitoring is carried out each year in Gunbower Creek through The Living Murray program, a joint initiative of the New South Wales, Victorian, South Australian, Australian Capital Territory and the Commonwealth governments, coordinated by the Murray Darling Basin Authority.