Carp numbers in the mid-Murray region have taken a hit with 30 tonnes of the introduced pest removed from Moira Lake this winter (2015).
The carp are destined to become fertiliser, leaving native fish in the system to enjoy reduced competition for food and habitat.
Carp removal is part of the long term management of Moira Lake which is located in the Murray Valley National Park, south of Deniliquin.
Senior Rehabilitation Officer Rick Webster said the project would provide a number of benefits to local rivers and wetlands.
“By removing the breeding adults from the population, we can help to control the overall number of carp in the region competing for resources,” Mr Webster said
“As well as competition for food and spawning sites, carp also play a role stirring up sediment in the water, eroding river banks and spreading disease.
“With ongoing efforts to control their numbers, we hope to reduce these impacts and see improvements in the range and health of aquatic plants as well as improved water quality,” he said.
To capture and remove the carp, nets were installed at the Moira Creek regulator. The lake was then drained through a single bay in the regulator, forcing the carp into the nets.
The process occurred after the close of the irrigation season which allowed the lake to be drained completely and a natural drying phase to begin. The lake will be re-filled as high natural flows occur within the Murray River during winter.
Mr Webster said the Moira Lake was once a haven for native fish and an important resource for Aboriginal people.
“In the mid-1800s commercial fishing companies in the area reported annual catches of at least 160 tonnes of native fish from the Moira Lake and nearby Murray River, from Picnic Point to Barmah,” he said.
The site has degraded since European settlement but the re-introduction of drying phases, environmental flows and carp control are helping to restore the health of Moira Lake.
Mr Webster said the National Parks and Wildlife Service would continue to engage private contractors on a yearly basis to remove carp from Moira Lake.
The NPWS is also looking to minimise impacts of carp in other Murray Valley wetlands such as Horseshoe Lagoon. There, carp screens have been installed to prevent adult carp entering the lagoon, allowing for an improvement in the health of the lagoon’s aquatic plants.