This disease is caused by the Aphanomyces invadans fungus – a fungus that is only known to cause disease in fish.

Aquatic biosecurity manager for NSW DPI, Jane Frances, said Epizootic Ulcerative Syndrome – more commonly known as red spot disease – showed as red lesions or deep ulcers on the skin of infected fish.

“Outbreaks of red spot disease are reasonably common and usually clear up naturally,” Ms Frances said.

“If caught, severely ulcerated fish should not be eaten or thrown back into the river.

“They should be quickly and humanely euthanased by removing the head and be buried away from waterways.

“Healthy fish with no sign of red spot disease can still be caught and consumed.”

Ms Frances said red spot disease had been reported in a number of coastal freshwater catchments this year.

“In some catchments outbreaks have been associated with acid water run-off, particularly after heavy rain following a prolonged dry spell,” she said.

“NSW DPI staff will continue monitoring the Myall Lakes and other nearby waterways where red spot is suspected. Anglers who catch any fish they think may have red spot disease should report their suspicions to NSW DPI on 1300 550 474.

“This will help us target our sampling, so that we can get a better understanding of the spread of the disease, affected species and possible triggers that could have caused the outbreak.”

Further information is available at www.dpi.nsw.gov.au or by calling 1300 550 474.