Yellowtail Kingfish (YTK) is the main cultureed finfish in SA and this industry has great potential to expand in other states of Australia. One of the major inefficiencies identified is feeds and feed management in CST’s YTK production. Henceforth, the newly formed CST RMAG has identified improving FCRs in YTK operations as an urgent priority. Upon reflection, the production efficiency of YTK by CST has been hindered by the poor understanding of feeding strategies, sea cage biomass determination, growth performance and the nutrient requirements of YTK at different life stages and water temperatures. Research in this project will specifically address each of these topics. This information is essential as YTK are exposed to sub-optimal water temperatures at most times of the year in SA. All-year round management strategies based on sound information need to be developed and implemented to maximise the production efficiency.
Despite the development of growth-ration curves for YTK by external consultants, CST is still experiencing problems establishing profitable feeding regimes that aim to reduce end of cycle FCR to less than 1.70:1.00. This level may or may not be achievable and, apart from accurate feeding, depends on many factors including diet composition, seasonal water temperature fluctuations, genetic background etc. It has also become apparent that in order for CST to gain market acceptance for their Yellowtail Kingfish products on a global basis the issue of sustainable production needs to be addressed. In order to address the issue of sustainability detailed changes to current dietary formulations for YTK, which contain high levels of fish meal and fish oil, will have to be made. Species specific information regarding nutrient availability, growth performance, fish health and maximum dietary inclusion levels of alternative sustainable ingredients for YTK cultured at fluctuating water temperatures are required in order to make these changes.
Final report
Yeilowtail Kingfish, Seriola lalandi, is the main closed cycle flnfish cultured in South Australia (SA) and this industry has great potential to expand in other states of Australia. One of the major inefficiencies identified by industry was feeds and feed management in Yellowtail Kingfish production. Henceforth, the newly formed CST Research Management Advisory Group (RMAG) identified improving feed conversion ratios (FCR) in Yellowtail Kingfish operations as an urgent priority. The production efficiency of Yellowtail Kingfish by CST has been hindered by the poor understanding of feeding strategies, sea cage biomass determination, growth performance and nutrient requirements of Yellowtail Kingfish at different life stages and water temperatures. It was also apparent that in order for CST to gain market acceptance for their Yellowtail Kingfish products on a global basis, the issue of sustainable use of marine ingredients, such as fish meal and fish oil, for the production of Yellowtail Kingfish needed to be addressed. In order to address the issue of sustainability detailed changes to current dietary formulations for Yellowtail Kingfish, which contained high levels of fish meal and fish oil, had to be made. Species specific information regarding nutrient availability, growth performance, fish health and maximum dietary inclusion levels of alternative sustainable ingredients for Yellowtail Kingfish cultured at fluctuating water temperatures were required to make these changes. Overall, the outcomes that should arise from the commercialisation of research outputs from this project will be an improved feed management system contributing to a reduction in FCRs from above 2:1 to 1.7:1, and revised and more sustainable Yellowtail Kingfish diet formulations (i.e. 25-30% lower proportions of marine based proteins and lipids).
