Gladstone Fish Health Investigation 2011 - 2012 - Western Basin ...

ecognised expertise and research publications concerning aquatic environmental scienceincluding water quality; fish health and toxicology; and human health especially in relation tothe potential for transmission of diseases from marine species to humans.The Panel reviewed the Queensland Government’s monitoring regimes, results collected in2011 and analysis primarily focusing on fish health in Gladstone Harbour and surrounds, butalso considered water quality monitoring and human health issues where relevant andappropriate.The Panel acknowledged that this was a complex issue and supported the Government’songoing investigation of the issue, noting that good progress had been made. The Panelmade specific comments and recommendations in relation to the issues of fish health, waterquality and human health with a view to identifying a possible cause(s) of the fish healthissues being observed in Gladstone Harbour.In particular, the Panel emphasised the need for comparative information from similarunaffected systems to determine the scale of the problem being observed in barramundi andother fish species in the Gladstone area. It was recommended that a more sophisticatedstudy design be conducted, including baselines and trends during ’normal’ periods, andappropriate areas outside the Harbour to act as a form of control for comparative analysis.The Panel also recommended constructing a conceptual model to illustrate possible causeeffectrelationship(s) to help guide studies and eliminate potential causal factors.Stocking in Lake AwoongaBarramundi have been stocked in Lake Awoonga since 1996. According to the GladstoneArea Water Board website, over 4.54 million fish had been released into Lake Awoongaincluding 3.69 million barramundi, 465 718 sea mullet and 70 942 mangrove jack. Since2006, an additional 1.3 million barramundi have been stocked in Lake Awoonga. Until waterflowed over the spillway on 12 December 2010, the stocked fish had not been able tomigrate downstream because the dam had not overflowed for the previous 14 years. In 2002,the height of Awoonga Dam was raised.Calliope and Boyne Rivers flooding eventAbove average rainfall occurred in November and December 2010. Totals of 93 mm and587.4 mm respectively were recorded at the Calliope weather station, compared with themedian level of 69.4 mm and 95.9 mm respectively. The total annual rainfall in 2010 was1702 mm, the second highest level since records started in 1906 up until 2010 (the highestlevel was 1801 mm, recorded in 1956).For comparison, 1973 was a wet year across Queensland, which resulted in the Brisbanefloods in January 1974. The total annual rainfall at the Calliope weather station in 1973 was1326 mm, which was the eighth highest on record. The mean total annual rainfall is 854 mmand the median total annual rainfall is 811 mm.The rainfall in 2010/11 resulted in an annual stream flow in the Boyne River of 1 194 848 ML(measured between October 2010 to September 2011), the highest stream flow sincerecords started in 1984. This is greater than the full supply capacity of Wivenhoe Dam, whichis 1,165,238 ML. The monthly stream flow for December 2010 was 634 999 ML, also thehighest since records started.On 12 December 2010, Awoonga Dam overflowed and did not cease spilling until June 2011.On Tuesday 28 December 2010, the water level in the dam had reached its highest point10