12:00a.m. 14th January 2009

| By Bill Hoffman, Nicola Kerkenezov

A close up view of the two-headed fish embryo. Photo: Contributed

The presence of two-headed fish larvae at a Noosa fish farm may be the result of natural genetic variation but the state government has promised a thorough investigation into the cause.

Mature bass caught in the Noosa River last August, induced to spawn for a re-stocking program, produced hundreds of thousands of larvae, 90% of which had two heads and died within 48 hours.

Acting Premier Paul Lucas said people should not jump to conclusions until the bizarre incident was thoroughly investigated.

“Fish don’t have two heads, they generally have one. And let’s find out why that is the case,” Mr Lucas said.

“It might be a natural genetic variation, it may be something totally unrelated to farming but let’s make sure we can make the decision based on evidence.

“Presumably if there were toxins in the river, toxins would be identified by testing but I have been advised none have been identified but they are doing even more detailed testing now.’’

The Queensland Department of Primary Industries will conduct further tests.

The Australian Pesticides and Veterinary Medicines Authority has asked the Commonwealth Department of Environment, Water, Heritage and the Arts to provide advice following claims the fish may have been affected by chemical drift from a neighbouring macadamia farm.

Spokesman Dr Simon Cubit said there were more than 200 chemicals registered for use on macadamias including carbendazim and endosulfan.

Both those chemicals are banned in the United States.

“Hopefully investigations will determine if chemicals were involved and, if they were, what those chemicals were,” Dr Cubit said.

“Once this is understood, the next step would be to establish if the chemicals involved were being properly used according to label instructions”.

“Evidence that chemicals used according to label instructions led to adverse environmental impacts would give cause for the APVMA to reconsider appropriate regulatory measures.

"Chemicals used contrary to label instructions, on the other hand, would be an issue for state authorities.”

Dr Cubit said the registration status of carbendazim was already under review by the APVMA because of concerns it could cause developmental abnormalities in experimental animals and might pose a potential public and occupational health and safety risk.

He said endosulfan had recently been reviewed by the APVMA and scientific evidence suggested its use was appropriate given the controls in place.

A University of Sydney lecturer in aquatic animal health, Matt Landos, said it was possible chemical run-off had caused the deformities.

“For the fish larvae, the most minute of doses can impact on their cells and cause damage,” he said.

Sunshine Coast division 12 councillor Lew Brennan refused to weigh into the debate saying the matter was up to the DPI&F and an issue “between the scientist and the federal government about registered pesticides”.

Noosa’s waterways are still among the cleanest according to a 12-month aquatic ecosystem health monitoring program coordinated last year by the south-east Queensland healthy waterways partnership.

Noosa’s pristine estuaries slipped from an A to an A minus while the catchments maintained a solid B rating in the healthy waterway report card for 2008, released in October.