Pirozzi I and Booth MA (2009) The effect of temperature and body weight on the routine metabolic rate and postprandial metabolic response in mulloway, Argyrosomus japonicus. Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology, 154, 110-118.

Available online: http://dx.doi.org/10.1016/j.cbpa.2009.05.010 

Summary

NSW DPI Fisheries is conducting a collaborative research project to improve our understanding of the nutritional requirements of cultured mulloway. Part of this project is to develop and construct nutritional models that allow nutritionists and farmers to predict how much of the ingested energy or nutrients in feed are converted into edible tissue, used for metabolic purposes or lost to the environment. Two of the major factors affecting these so called bio-energetic models and their predictive capacity for finfish are water temperature and fish size, especially the effect these factors have on metabolic rate.

In Australia, the majority of cultured mulloway in NSW and SA are grown in sea-cages. The water temperature at these sites varies considerably and can range from as low as 12°C in the winter to 25°C in the summer. In situations where mulloway are grown in inland or coastal lagoons summer water temperatures may exceed 30°C. In order to improve the predictability and usefulness of our bio-energetic model for cultured mulloway an experiment was done to investigate the impacts of different water temperatures (14, 20 or 26°C) on the routine metabolic rate of mulloway weighing between 60 to 1140g before and after a single meal. Metabolic rates were estimated by holding mulloway of various sizes in 200 litre experiment tanks and recording changes in the concentration of dissolved oxygen in the tank water over time. 

Our results indicate that routine metabolic rate and the energy required to digest and metabolise a single meal represent a significant energetic cost in the overall energy budget of mulloway, accounting for nearly 30% of the digestible energy content of a single meal. This study has also determined a series of equations relating body size, water temperature and ingested energy to the expenditure of metabolic energy before and after a single meal, which will be used to refine and improve bio-energetic models for mulloway.