2012/737 Yellowtail kingfish health workshop and feed analysis

Since December 2011, CST has experienced unprecedented mortalities in both its 2011 and 2012 year classes of Kingfish. In addition to the mortalities, fish performance has been severely compromised, with a 30% -50% reduction in growth recorded in the 2011 and 2012 year classes respectively. This project addressed the need to further CST’s understanding of the disease issues severely impacting YTK production. Through a workshop and dietary analysis it was anticipated that CST would be able to develop a disease investigation plan and remedial strategy for immediate implementation. If successful, this project will provide the first step towards rebuilding a sustainable YTK industry in Australia.

The workshop found that the requirement for Taurine (Tau) by marine carnivores such as YTK is high and the level in the diet should be between 0.5-1.0%. Considering this recommendation it would appear that all diets are deficient in Tau, particularly those for larvae and +1kg fish. Hematological parameters and gross hepatic observations were consistent with a Tau deficiency. They recommended that the addition of crystalline Tau should be immediately adopted to mitigate losses; and that development of a routine feed sampling and analysis protocol is required as diets often do not contain the level of nutrients specified.