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

Figure 28. (a) Mullet caught in Rodds Bay displaying minor redness/pinpoint marks on the ventral surfaceand caudal peduncle. The redness around the operculum was a result of the capture by net; (b) Mulletcaught in the Calliope River showing general redness; (c) Mullet caught in Rodds Bay with ulcerativelesion on the caudal peduncle.Histopathology and residue testing Phase 1Only two mullet were examined by necropsy and histology during Phase 1 of theinvestigation. They were submitted by a member of the public from the Gladstone area, butno location was provided. Both fish exhibited skin redness with inflammation of the dermisand loss of epidermis. No bacteria or fungi were present in the skin lesions. Some inorganicsediment was found in association with sloughed epidermal cells and mixed with sloughedcells between gill filaments. A range of minor lesions related to parasites were presentinternally, however these are normal.Mullet from the Kolan River (Bundaberg) and Turkey Beach (Gladstone Harbour) were testedfor chemical residues using gill, liver and muscle tissue from two fish from each site. Themetal concentrations for the reference site (Kolan River) exceed those from Gladstone formost metals (i.e. aluminium, iron, copper, zinc, arsenic, selenium, silver and barium). Othermetals, including lead and mercury, showed no obvious difference between the referenceand Gladstone Harbour sites. No organic chemicals were detected.Observational findings Phase 2Mullet sampling during Phase 2 was conducted in April 2012 and was repeated in June/July2012. The results from these sampling events are recorded below, along with a summary forPhase 2.50