The southern Bluefin tuna industry in Australia is limited by catch quota. Increased competitiveness through production efficiency is the main way to improve the value of the industry. Improved performance can be achieved by maintaining a high health status which consequently minimises stress, reduces mortalities and optimises production. Since 2002 there has been a significant fall in revenue (prices down over 50% and strengthening of the Australian dollar). The worsening financial parameters, combined with the intrinsic high ‘value’ of each fish, have placed a greater focus on all aspects of the industry and particularly stress impacts limiting production. Mortality is an obvious area and the current, increased level is not acceptable. Possibly more important, parasites may cause economic costs to the tuna industry in lost growth and condition. There is a potential for increased productivity through the reduction of parasite loads. This can be only achieved through better understanding of the current dynamics of parasitic infections and the cost of parasitic infections to the SBT production.