A fish virus that causes organ failure has been confirmed as the culprit behind a string of fish deaths in the central west of New South Wales.
Key points:
- A fish virus has been confirmed as the cause of a significant fish kill at Lake Wallace near Lithgow
- The virus kills introduced, pest redfin but can also harm native fish
- Researchers are concerned about the endangered Macquarie Perch if the virus starts spreading
The NSW Department of Primary Industries has been investigating a significant number of dead redfin fish at Wallerawang, Oberon, Orange, and Lake Burrendong.
The Lithgow City Council has reopened Lake Wallace at Wallerawang to people after test results confirmed a deadly virus was behind hundreds of fish deaths.
Epizootic haematopoietic necrosis (EHN) is a species-specific disease that kills redfin through organ failure.
Redfin, also known as European perch, are an invasive pest in Australian waterways but the virus has been known to infect other native fish.
The virus is known to be naturally present in Australian waterways and was first discovered at Blowering Dam near Tumut in 1986.
The virus does not affect humans and fish from infected areas are safe to consume.
DPI Fisheries spokesperson Sam Davis said there was a particular concern with the endangered Macquarie perch population at Bathurst.
"We do have a population of Macquarie perch in the Central Tablelands region that we have very grave concerns for," he said.
"If the virus gets amongst that population it could probably bring the end to it."
Macquarie perch are listed as endangered in NSW and are found in upstream areas of the Murray-Darling Basin including the Lachlan, Murrumbidgee, and Murray rivers as well as some rivers in the Hawkesbury and Nepean catchments.
Ms Davis said the the virus is known to be present in southern waterways and the spread to the central west is concerning.
"Typically the virus has been confined to areas much farther south in the state so it suggests to us that potentially the virus is on the move," she said.
To help stop the spread of the virus it is illegal to possess live redfin and to use redfin as bait in any inland waterway in NSW.
Fishers are also encouraged to wash and dry vessels, trailers, and fishing gear before moving to new waterways.