The potential for oil pollution in the Ross Sea is increasing as shipping activities increase due to base operations and tourism. The effects of diesel fuel oil on Antarctic fish survival and physiology was examined. Oil contaminated water was created by utilising the water soluble fraction of the oil. Oil was placed on top of the water and current causes the oil to remain as a discrete layer. ... Water soluble components of the oil dissolve in the lower aqueous layer and the contaminated water was used on the fish. Fish were placed into varying concentrations of the contaminated seawater to determine the 48 hour lethal dose. Following this, fish were placed into a sub lethal concentration for varying periods of time in order to determine any time dependent changes. Visual observations were made on the state of the fish. Respiration rates of the fish were monitored by oxygen uptake in a closed system. Blood samples were taken for haematocrit and plasma for analysis. Gill, liver and heart samples were fixed for electron microscope work. To determine any long term effects of fuel contamination fish were kept for7 days in a 20% concentration of contaminated water. After 7 days, the influence of the diesel fuel on the respiratory system and blood chemistry was examined. Closed box respirometry was used with one group of 10 fish (5 control & 5 oil exposed) to determine their ability to extract oxygen from the water. Another group of 12 fish (6 control and 6 oil exposed) were killed with an overdose of anaesthetic and then blood, gill and liver samples were taken. The blood was immediately analyzed for % haematocrit and haemoglobin concentrations. Plasma samples were collected for analysis of chloride concentrations and osmolarities. Gill and liver samples were fixed for examination under the electron microscope to determine any morphological or ultra structural changes as a result of petroleum exposure.