Southern Bluefin Tuna are large, fast, pelagic predators and as such probably have a very different metabolism to most other species of cultured finfish. There is a need therefore, to develop a comprehensive understanding of the metabolic rates of SBT as a basis for improving our management and husbandry of this species.

Nutrition (food conversion ratios), responses to water quality (limiting oxygen concentrations), response to predators, fish health and environmental outcomes (e.g. waste production) are all linked to metabolic rate. Improving the management of fish in culture including the development of new feeds, optimising production and product quality and assuring sound environmental outcomes are all dependant on developing this basic knowledge.

At the Southern Bluefin Tuna (SBT) Aquaculture Subprogram Steering Committee Workshop, held on the 6th November 2002 in Port Lincoln, physiology was identified, by both industry and research sectors, as a major research priority. In particular, it was recognised that a need exists to measure SBT size-specific metabolic rates under a variety of circumstances, including tow history, handling, cage acclimation effects, water temperature, changes in oxygen levels (especially hypoxia), levels of cage fouling, feeding activity and food type. Similarly, data on SBT’s metabolic responses to stressors such as microalgae, sediment, noise and predator presence were also considered important.

This project will also provide invaluable information about metabolic rates that will inform research being conducted on the species in the wild and thereby enhance our understanding of the overall biology of this species. Importantly, the data could be used to calibrate information from tagged fish currently being collected as part of CSIRO’s ongoing research into the movement and ecology of SBT using archival tags.

The project will address Industry needs by producing the following outcomes:
· Measurements of oxygen consumption on commercial-sized SBT
· Incorporation of those data into metabolic model for cultured SBT
· An investigation of the usefulness of microsensor technology in monitoring tuna respiration in a commercial environment.