The reverse precautionary principle: science, the environment and the salmon aquaculture industry in Macquarie Harbour, Tasmania, Australia

Science is frequently used by opposing sides in environment–development debates. Scientific input from an environmental perspective can be inhibited if those in favour of development control research funding. We test whether such a situation can result in outcomes desired by neither of the protagonists, and seek to identify how negative outcomes can be avoided, using the example of fish farming in Macquarie Harbour, Tasmania. A marked decline in dissolved oxygen (DO) at 19–21 m depth in Macquarie Harbour, Tasmania, occurred between 2009 and 2011. DO continues to be low. DO change was associated with changes in the benthic biota, with effects extending from fish farms into the Tasmanian Wilderness World Heritage Area and threatening a Tasmanian endemic fish. The reverse precautionary response of industry and government was to undertake further research because the causes of the changes were not fully understood. We present simple graphs and analyses that suggest that the only substantial predictor of benthic DO reduction is fish production from marine farms, with variability in discharge, catchment rainfall, wind speed, sea surface temperatures and sea level pressure having no effect. Adaptive management of fish farming in Macquarie Harbour seems to require an estuary-wide approach rather than the current attention to the effects of single pens. The broader implications of the case study are that the science related to the environmental impacts of an industry needsto be undertaken by scientistsin secure positions funded independently of industry and government.