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

Phase 1: Fish Health Survey – Gladstone Harbour(August 2011–February 2012)OverviewThe first fish samples were provided to Biosecurity Queensland from August 2011. In lateSeptember 2011, Fisheries Queensland commenced monitoring fish health in GladstoneHarbour. The monitoring was based on a visual examination of fish and crustaceans. Theinitial monitoring focused on understanding the distribution of fish within the Harbour withexternal symptoms and the severity of those symptoms.A number of specific species were monitored in more detail after reports of high levels ofabnormalities were received from recreational and commercial fishers. These included trawlspecies (banana prawns and trawled fish), mud crabs, sharks, scallops and barramundi.Field staff were given training on the collection of biological samples (skin swabs, tissuesamples from various organs, collection of observed parasites), and photographedabnormalities as reference material. After the initial monitoring trips in September andOctober 2011, the definitions of skill discolouration, eye condition and lesion categories wererefined and used in the rest of Phase 1 and in Phase 2 (Appendix A). After the initialmonitoring, Fisheries Queensland established a routine monthly fish health monitoringprogram.Study areaThe principal study area was Gladstone Harbour and adjacent waterways, encompassing theareas closed to fishing during September 2011. Sampling took place at a range of siteswithin the principal study area to allow an understanding of fish presenting with signs of illhealth and their potential movement within the principal study area. The sites sampled werethe Narrows, Hamilton Point, Calliope River, Gladstone Harbour (trawl), spoil ground, UpperBoyne River, Lower Boyne River and Rodds Bay (Figure 1).The main reference sites (i.e. for comparison with the principal study area) for the structuredmonitoring program included the nearby Fitzroy River to the north and waters adjacent toBundaberg with its nearby coastal waters to the south. Both of these sites have various landuse activities conducted adjacent to the waterways. These sites are useful as reference sitesgiven their environments, fish communities and geographic location. It must be noted that notall species of finfish and crustaceans were sampled at each site because of differences intheir distribution and the suitability of sampling methods in different areas. In Phase 1 only,occasional samples were also collected from within the principal study area but outside of thelocations described in Figure 2.13