Pest fish removal benefits trout cod

Wednesday 29 August, 2018
More than 300kg of carp and redfin were removed from sections of Hughes and Seven creeks during a two week period to protect populations of threatened native species including trout cod and Macquarie perch.

Goulburn Broken CMA Riparian and River Channel Manager Jim Castles said Macquarie perch was a nationally threatened species that is found in only 11 population across Victoria, seven of which are in the Goulburn Broken Catchment. 

“Trout cod are also listed as threatened in Australia, and an important self-sustaining population exists in the Seven Creeks between Polly McQuinn Reservoir and Galls Gap Road,” Mr Castles said. “Redfin are a serious threat to the survival of Macquarie perch and trout cod as they prey on young fish and compete for food.”

The Goulburn Broken CMA has been working with local landholders, community and fishing groups along the Seven and Hughes creeks for many years to improve and protect habitat for native fish. Each year surveys are undertaken to monitor the effects of this work. Surveys done in conjunction with DELWP’s Arthur Rylah Institute in early autumn this year indicated large increases in redfin numbers in areas inhabited by Macquarie perch and trout cod in both creeks.

“Redfin numbers in Hughes Creek, for example, were the highest since fish surveys commenced in 2006,” Mr Castles said. “This was probably due to the localised natural flooding in December 2017 that wasn’t good for native fish spawning but suited carp and redfin. It is important that we protect these threatened populations of Macquarie perch and trout cod so we targeted specific areas - Hughes Creek upstream of Avenel through an area known as the gorge and the section closed to fishing on the Seven Creeks – for redfin and carp removal.”

A total of 366 redfin (7kg) and 93 carp (190kg) were removed from 7.3km of Hughes Creek.  Of the redfin removed from Hughes Creek, 97% were less than one year old. A total of 407 redfin (6.6kg) and 46 carp (105kg) were removed from 6km of Seven Creeks.  Again, a large proportion of the redfin removed from Seven Creeks were less than one year old.

“Hughes and Seven creeks have experienced low or no-flows in recent years, which puts massive pressure on the native fish populations they contain,” Mr Castles said. “We know it’s important we get redfin numbers down after a large breeding event to have the greatest impact. Through funding from the Victorian Government’s Biodiversity On Ground Action Grants program we were able to carry out this removal work and further exotic fish removal is planned in these targeted areas again next month (September).”

 Hughes and Seven creeks are part of the Victorian Government’s Flagship Waterways program. In-stream and stream side (riparian) habitat improvement works are funded through the $222 million Water for Victoria initiative.