In line with the pervasiveness of gut related illnesses, a recent study by the Tasmanian Institute of Agricultural Research (TIAR) on microbial communities of the hindgut of salmonid fish has shown that these microbial ecosystems are heavily influenced by the local aquatic environment and to some extent diet formulations (Bowman et al 2006). According to this report the intensive feed regime combined with local environmental conditions can lead to overgrowth of certain bacterial species within the gut. The higher number of bacteria in fish hindgut during summer time compared to autumn suggests that the temperature may be instrumental in promoting an overgrowth of pathogenic species. The activity of these bacteria may then lead to a suboptimal feeding and health of the salmon. Clinically this is associated with loss of appetite and reduction in growth rate and a diarrhoeal-like faecal excretion is observed (Bowman et al 2006).

Little is known about the exact pathogenic mechanisms used by these bacteria to cause disease and there is a real need to alleviate pressure on the aquaculture industry from diseases caused by these bacterial species. This project as shown in the objectives is to be run parallel to another project recently accepted by the seafood CRC in providing information on these pathogenic bacteria to be used for testing the efficacy of any isolated probiotics.