G-MW staff remove carp from the Murray River via the fishway at Torrumbarry Weir.
A small group of Goulburn-Murray Water employees have made a big contribution to the preservation of native fish populations along the Murray River.
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They have been busy removing carp from the river at Torrumbarry Weir.
So busy, they’ve disposed of an estimated 120,000 of the pest fish since 1992, when a fishway was constructed at the weir.
Fishways allow fish to bypass barriers such as weirs and other regulators so that they can migrate along the river. They play a crucial role in sustaining native fish populations in heavily irrigated areas.
However, Torrumbarry’s fishway is unique in that it also includes a ‘carp trap’.
This trap is a large metal cage at the end of the fishway, that all fish that pass through the fishway are caught in.
G-MW’s Torrumbarry storage officers lift the cage out daily and separate the fish, sending the native fish down a fish-slide that takes them upstream of the weir, and sending the carp into a separate cage.
The carp in this cage are donated to Charlie Carp, a Deniliquin business that turns carp into fertiliser.
The carp are separated from the native fish, which are free to continue their journey upstream.
Torrumbarry senior storage officer Luke Simpson said filtering the carp out of the fishway could be a significant undertaking.
“Often we get just a few carp a day, but we have had days where we have caught more than 2000 carp in the trap,” he said.
“During times like this, we need to lift the trap out three times per day to get rid of all the carp.
“We’re a pretty small team here at Torrumbarry, so it can be a fair bit of work.”
Carp are bottom feeders. They stir up mud on the riverbeds, which affects water quality and prevents sunlight from reaching aquatic plants that native fish need for food.
Since the fishway was installed in the early 1990s, more than 120,000 carp have been removed using the fish trap.
Mr Simpson said he was glad the Torrumbarry team could do their bit in ridding the system of the invasive species.
“Fishways like the one at Torrumbarry have proven incredibly valuable to supporting native fish populations,” he said.
“We get plenty of silver perch, golden perch and bony bream through the fishway.
“Carp are obviously one of the main threats to these native fish, so it is really beneficial to be able to remove the carp while also providing safe passage to the native species.”
Torrumbarry Weir is managed by G-MW on behalf of the Murray-Darling Basin Authority.
The carp are donated to Charlie Carp, a business that turns carp into fertiliser.
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