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

FinfishObservational findingsDuring September 2011, 52 fish were caught and observed in the Fitzroy River includingbeach salmon (2), blue threadfin (20), catfish (11), king threadfin (13), pikey bream (4) andtripletail (2). No skin discolouration, lesions or other signs of ill health were observed.During October 2011, blue threadfin (3) caught in the Narrows and Rodds Bay and a kingthreadfin caught in the Narrows were observed to be in good health, while a catfish and kingthreadfin caught in the Boyne River showed general redness on the skin and fins.During November 2011, 401 finfish were observed from the Fitzroy River (9), Hamilton Point(1), Rodds Bay (200) and Bundaberg (191). Of these fish, a single whiting caught inBundaberg was observed to have a lesion that was described as a recovering wound, and 60of the 200 whiting caught in Rodds Bay displayed some minor skin condition. These mild skinconditions consisted of areas of slight discolouration, often with a single red dot under ascale.During December 2011, observations were made of 87 finfish caught during both netting (52)and crabbing trips (35). During net fishing trips, other species of finfish were caught in theCalliope River (7), Hamilton Point (1), Rodds Bay (33) and the lower reaches of the BoyneRiver (11). Of these, eight fish showed signs of minor redness, while a black jew caught atHamilton Point had more general skin discolouration. During crabbing trips in the CalliopeRiver, the Narrows and South Trees Inlet, three fish were observed to have minor redness.These fish were a pikey bream from South Trees Inlet and two cod from the Narrows.In January 2012, observations were made of 42 fish from the Gladstone area. Of these, oneblubber lip (sweetlip) caught at Hamilton Point showed small areas of discolouration. Of 27catfish captured from the Calliope River and the upper reaches of the Boyne River, 19exhibited small areas of skin discolouration with an additional two showing discolourationmore broadly across the body. One of these fish also had an abnormal eye. Four catfishcaught in the upper reaches of the Boyne River had lesions present on the skin. A further 87fish were observed from the Fitzroy River and Bundaberg (reference sites). The specieswere dominated by catfish (27) and bony bream (42) with javelin fish (17), and a spotted scatwas also captured. All fish observed in the reference sites were considered to be in goodhealth with no abnormalities observed.During February 2012, observations were conducted aboard commercial net fishingoperations at Rodds Bay and at Colosseum (halfway between Rodds Bay and the mouth ofthe Boyne River). Blue salmon (11), catfish (7) and a single sweetlip were amongst thecatch. A single catfish was observed with redness to the pelvic fins, with the remaining fishshowing no signs of ill health.Histopathology and chemical residue testingTesting has also been carried out on a wide range of bony fish species including whiting,goldspot grouper, spangled emperor, flathead and scat. Many of these samples were privatesubmissions.Skin abnormalities from other finfish species were generally mild and not due toNeobenedenia sp. Findings included localised skin inflammation, skin erosion, fibrosis(scarring), reddening, dermal haemorrhage (bleeding of the skin), epidermal necrosis (celldeath) and oedema (swelling).72