Winton Wetlands Fish Survey, Spring 2023
Monitoring the biodiversity of our wetlands helps us understand the ecosystem and allows us to track the restoration of the ecosystem and its ecological functions. Our surveys in spring also gave us the opportunity to remove feral fish (mainly carp and goldfish) from our water bodies, some of which will receive our first lot of Growling Grass Frogs #taskforcegrowler https://wintonwetlands.org.au/growling-grass-frogs/ if we have a successful breeding event with them this spring/summer.
In September 2023, with the aid of Nature Glenelg Trust’s Scott Huntley and his “shock boat,” Lance Lloyd, and other WWCoM staff were able to remove 230 carp and wild goldfish, totaling about 85kg, from our Mokoan and Duck Ponds. Interestingly, our Cod Pond now seems to be free of carp altogether, with no carp or goldfish found in both the May or September surveys despite similar effort and multiple gear types. We are taking it as a big win! The Duck Pond is also carp-free, but it does support some wild-type goldfish, some of which were very large at 270 mm long.
Our biodiversity results are also good news. We have six known native species, five of which were caught or observed. Of the over 4,000 native fish caught, these were dominated by Carp Gudgeons (a small-bodied native fish important for ecosystem health) and smelt populations (another important native fish) increasing over time. Importantly, native fish vastly outnumbered the other invasive fish we have, the Eastern Gambusia, by about a ratio of 4:1!
Further, on the biodiversity front, we also captured two species of turtles: Long-necked turtles and Murray River turtles, including hatchlings of both species! Over 95% of hatchlings are lost each year due to fox predation of nests, but we are regularly reducing the fox populations and protecting turtle nests when these are found, giving these important aquatic animals a chance to hatch and grow in our wetlands. 1 Million Turtles Community Conservation Program Turtles Australia Inc Turtlesat – Turtle Survey and Analysis Tools
The very big news, we save for last! We managed to recover one of the conservation-listed fish, the Southern Pygmy Perch, which we stocked in January and March this year. The fish was 71 mm in length and very healthy. Considering the fish we stocked were about 30-40 mm in length, this individual has grown considerably. Given the thousands of fish in that location, recapturing one is indicative that it is likely that there is a population of this fish present, and we are hoping to find that the species will have bred when we survey in Summer 2023/24. North Central CMA Goulburn Broken CMA North East CMA
Thanks to above organisations, as well as Wettenhall Environment Trust, Murray-Darling Basin Authority, #Murray–Darling Healthy Rivers Program, Department of Climate Change, Energy, the Environment and Water, DEECA Hume, Swamps Rivers and Ranges
Southern Pygmy Perch 71mm
These are wild type goldfish these are 150mm to 270mm in length – and while not as large as Carp can get,
at this size they start to impact on our wetland ecosystems.
Hatchling long neck turtle at Duck Pond