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

ever at 44 m; 4 m above the spillway level. In 2013, a higher flood peak in the Boyne Riverwas reached at 48.3 m, more than twice the height above the spillway in 2010/11.It was estimated that 30 000 large barramundi were washed out of Awoonga Dam into theBoyne River between December 2010 and March 2011, as the result of water flow over thespillway. If the average weight of these fish was ten kilograms, this represents an additional300 tonnes of barramundi introduced into the Boyne River and Gladstone Harbour.Recreational catchA charter operator in the Gladstone region, Johnny Mitchell, provided a report to FisheriesQueensland of his observations of the recreational catch of barramundi in the Boyne Riversystem in 2011 (Appendix E).His report documented the movement of large schools of large barramundi (Figure 2), witheach school exceeding an estimated one thousand barramundi moving from the freshwatersection of the Upper Boyne through the tidal sections to the mouth of the Boyne River andinto the Harbour. Within a week of the initial overflow at Awoonga Dam, he “witnessed manynew fresh and lively arrivals (escapee lake fish), detected with the use of high definitiondepth sounder in areas within the harbour up to 43 km from the dam wall” and reported highcatches of barramundi in the Harbour up to 50 km north and south of the Boyne River in lateJanuary 2011. Anglers reported catching 12 to 15 barramundi averaging around 100 cm injust one to two hours of fishing. Many of the fish showed signs of physical damage to the jawor head; some wounds were severe, although advanced healing was obvious.Figure 1. A school of large fish in the Boyne River detected on a fish finder during recreational fishing in2011.11