The lipid composition of five species of marine finfish from temperate Australian waters was determined. Claims that the lipids of Australian fish contain high levels of omega-6 fatty acids and arachidonic acid (AA) were investigated. Individual fish were analysed from samples collected at three locations and two seasons, and they were found to have fatty acid compositions of similar nutritional value to those from northern hemisphere temperate waters. Levels of AA, eicosapentaenoic acid and docosahexaenoic acid were also found to be comparable. The variability in fatty acid compositions was greater between samples taken from different locations than from different seasons. Lipid contents and compositions were found to exhibit some species-characteristic nature, indicating a need for accurate species identification. A high-performance liquid chromatographic (HPLC) method for fish identification was developed, which was successful. The application of HPLC to processed fish was investigated and it was found to be suitable for gamma-irradiated and infrared dried fish, but not for those that had been smoked or microwave cooked. / Doctor of Philosophy (PhD)