The purpose of the application is to seek funds to support travel to attend the 19th meeting of the Commission for the Conservation of Southern Bluefin Tuna (CCSBT) to be held in Takamatsu City, Japan. In addition, I intend to visit a number of research facilities to further understand issues associated with tuna propagation techniques, kingfish husbandry including nutrition and disease, and fisheries management issues that relate to South Australian fisheries and aquaculture industries (e.g. stock enhancement, regional fisheries management, ranching of other species, recreational fishing).

Since 2010, the SA government has had input into the future decision making processes of CCSBT. These negotiations align closely with a number of key science, sustainability, social and industry development strategies in relevant SA and Australian strategic plans, such as the SA State Plan and SA Food Strategy 2010 – 2015.

Kinki University has developed a successful program to close the life cycle of Northern Bluefin Tuna. South Australia has had success with the closing the life cycle of the Southern Bluefin Tuna (SBT) however there are significant challenges ahead of this new and emerging industry to commercialise this activity. Visiting Kinki University will provide the SA government with a better understanding of the future need for infrastructure and R&D expertise to overcome the current bottleneck and to develop a new industry.

Discussions with Fisheries Managers and researchers will inform PIRSA in relation to decision making processes around the management and development of fishing and aquaculture in South Australia.

SBT:
There is a need to better identify the relationship between hormonal treatment and spawning performance as this will determine the hormonal manipulation strategy. There is also a need to better
understand factors associated with broodstock mortality, as currently 30% of the broodstock die every year and thus need to be replaced.

We need to develop methods of ensuring that all females participate in spawning every year and how to extend the spawning cycle to have eggs for four months of the year.

There is a need to advance the initiation of spawning to October (from the current norm of February) so that the fingerlings are ready to be transferred to sea cages sufficiently early in the calendar year for optimal seawater temperatures.
SBT broodstock reach spawning age at about 12 years of age. There is therefore a need to examine alternative technologies and approaches to obtain tuna seed from younger fish.

YTK:
This genetic management and selection project is needed to maintain a commercial advantage in a highly competitive market and as a management tool to prevent inbreeding.

It is difficult to source wild YTK broodstock, and the current stock are getting older and larger. There is a need to source new broodstock, and it will be advantageous to use selected F1, provided they can be genetically managed.

With aquaculture production increasing rapidly in South Australia, as well as several other states including Tasmania, there is an increasing level of concern about the trade-offs between economic returns and environmental sustainability. In Australia, most aquaculture, particularly in-sea aquaculture, is undertaken on a single species basis. For finfish, which are fed a diet based on either baitfish or pelleted feeds, this means that a considerable amount of nutrients are released into the environment. For example, for the two main species farmed in Spencer Gulf in South Australia, southern bluefin tuna and yellowtail kingfish, for every tonne of production, as much as 500 and 200 kg respectively of nitrogen is released into the environment. In areas of high production, these wastes have the potential to stimulate plankton blooms and/or smother the benthos. As a consequence, stocking levels are closely regulated to reduce the potential for environmental harm, and there is considerable interest in methods for removing wastes and/or mitigating their impacts. IMTA thus has the potential to be utilised in Australia to both decrease the environmental impacts of finfish farming, and increase financial returns to the aquaculture industry. If successful, IMTA could be used to reduce nutrient inputs from farming into the marine environment, giving industry the flexibility to maintain higher stocking levels, leading to more optimal use of resources. Before IMTA can be undertaken on a commercial scale in the warm temperate waters of southern Australia, however, there are a number of questions that need to be addressed. These include what species and farming systems are suitable, what is the potential for the species used to act as an intermediate host for parasites of other species in the system, and are their any food safety issues that need to be addressed.

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.