About 10 years ago the Pioneer River which runs through the North Queensland town of Mackay flooded and some mangroves died. A few years later the World Wildlife Fund (WWF) launched its ‘Save the Reef’ campaign focusing on claimed impacts of farming on the Great Barrier Reef and an academic at the University of Queensland, Norm Duke, released a report implicating cane farming in the mangrove dieback at Mackay in particular farm runoff containing the herbicide Diuron.
The WWF campaign generated political momentum for some sort of action and a Reef Taskforce was formed to advise government. At the time I was working for the Queensland Sugar Industry and made a member of the Taskforce. It was clear that there was no substantial evidence for an impact from farming on the reef, but the government had committed itself to there being a problem and the Taskforce was to conclude as much.
Dr Duke’s unpublished report to the Queensland Fisheries Service became a key document for the Taskforce, purportedly providing evidence for “localized deterioration on individual nearshore reefs” from farm runoff.
At the time I explained that the Duke report, and the hypothesis that the dieback was a consequence of the herbicide Diuron, had some major flaws, including: “Only four of 21 potential sites were tested for Diuron. Traces of Diuron were found in the sediment at all four sites. This included the control site at which there was no mangrove dieback. In other words, Diuron was found at one site where there was no mangrove dieback as well as at three sites where there was mangrove dieback. No evidence was presented to indicate that the levels of Diuron at any of the sites were herbicidal.”
But the campaign against the farmers supported by a compliant media rolled on, politicians were elected on the basis they cared about the reef including mangroves, plans were developed to save the reef from farming, hundreds of millions of dollars provided for research programs to save the reef from farming. Indeed there is now a large bureaucracy including academics and sugar industry personnel associated with saving the reef.
There is ongoing monitoring of the stands of mangrove in the vicinity of Mackay but there is still no evidence implicating the herbicide Diuron in the mangrove dieback.
Indeed today I was assured by those who have spent years monitoring the mangroves that diuron can still be found in sediment, but it doesn’t seem to be affecting the mangroves that “there is no indication that the herbicides at the levels detected in the Pioneer River estuary have impacted on the health of the mangroves.”
I had a wander around the mangroves, including in the Bassett Basin near Barnes Creek, today with Carl Mitchell from Reef Catchments and John Abbot from the University of Queensland.
Jennifer Marohasy & Gary Johns, 2002, WWF Says ‘Jump!’, Governments Ask ‘How High?’ Institute of Public Affairs, Occasional Paper