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

BackgroundIn August 2011, the Queensland Government received reports of barramundi andsubsequently other species being caught with obvious signs of ill health, includingbulging/red eyes, blindness, severe skin lesions and skin discolouration.On 16 September 2011, Fisheries Queensland, in the former Department of Employment,Economic Development and Innovation (now Department of Agriculture, Fisheries andForestry (DAFF)), closed Gladstone Harbour and the surrounding area to fishing for a periodof 21 days, under section 96 of the Fisheries Act 1994 in response to concerns about humanhealth and to allow further testing to be carried out on the conditions affecting locally-caughtfish.From the initial testing of nine ill barramundi, two conditions were identified that wereaffecting barramundi in the Gladstone area: Red-spot disease (Epizootic Ulcerative Syndrome (EUS) or ‘red-spot’ disease), which iscaused by a fungus endemic to finfish species of mainland Australia. This condition wasonly confirmed in one barramundi from Port Alma, near the Fitzroy River; An external parasite Neobenedenia sp., which was affecting the eye and skinparticularly on some of the barramundi in Gladstone Harbour.Barramundi and other finfish species displayed a range of generally mild skin conditions fromlocalised skin inflammation, skin erosion and redness. No bacterial, parasitic or fungalpathogens were found that could explain the skin conditions.Reports were also received from the Gladstone Area Water Board that an estimated 30 000 1large barramundi entered the Boyne River in early 2011 when the Awoonga Dam spilled overfor the first time since 1996. Commercial catches of barramundi in 2011 were in excess of20 times the average annual Gladstone Harbour (Grid S30) catch from 2005 to 2010,providing support for this observation.In response to the fish health issues, the Queensland Government set up an investigationprogram that included fish sampling and testing, water quality sampling and testing, andinvestigation into human health concerns.Fisheries Queensland commenced monitoring fish health in Gladstone Harbour after theclosure of the Harbour was declared, and continued to monitor fish health in Gladstone andadjacent areas in conjunction with commercial fishers until September 2012. BiosecurityQueensland conducted examination of animals of particular concern, which were submittedby either Fisheries Queensland or members of the public.In October 2011, an Independent Scientific Advisory Panel was established to provideindependent scientific advice to the Queensland Government on the fish health investigationin Gladstone Harbour. The membership of the panel comprised eminent scientists with1Fisheries Queensland was advised verbally that an estimated 30 000 barramundi were washedover the spillway in 2010/11 and has used this figure in all its publications. However, in theGAWB Annual report 2011, 20 000 barramundi are reported as being washed over the spillway.Given that the commercial fishers caught almost 250 t of barramundi in Gladstone in 2011and theaverage weight of barramundi in October 2011 was 9 kg; it is estimated that the commercialfishers caught more than 27 700 barramundi. In the last quarter of 2011, catch rates were stillmore than two and a half times the pre-flood rate for this quarter, therefore Fisheries Queenslandbelieves that the figure of 30 000 barramundi being washed out of Awoonga Dam is anunderestimate.9