Through existing farming practices it is apparent that there are several factors which may be limiting production and ultimately revenue.
Firstly, there is a need to identify an “ideal production strategy” to achieve forecast production levels. As temperature significantly affects YTK growth, feed conversion ratios and health, it is essential that the relationship between growth and temperature is investigated in fish of various sizes. This information will enable CST to make informed decisions on size and time of stocking YTK into sea cages. It is anticipated that this will improve production through shortening the production cycle and will reduce the standing biomass in the water, ultimately increasing farm profitability.
Secondly, maturation may be a constraining factor in YTK production, reducing somatic growth. There are also flesh quality concerns which threaten sales of YTK harvested in November-December, a period when males exhibit maturation. However preliminary analysis of work carried out in Seafood CRC project 2008/901 suggests that male maturity did not have a significant deleterious effect on the flesh quality at that time. Though there are numerous strategies to manage maturation it is initially necessary to characterise the occurrence of maturation and the factors controlling it. With this information, appropriate mitigation strategies can be introduced resulting in economic benefits to the YTK industry.
Lastly, as production is poised to increase, it is imperative that substantial markets are developed for YTK product. One way of increasing sales is to ensure product sold is consistently of the highest possible quality. By attaining knowledge on the quality attributes, shelf-life and nutritional content of the product, producers will be able to tailor a product to specific market requirements. Likewise, as processing techniques and cold chain supply routes are diverse, it is imperative that information is attained on how these influence the quality of the product.
This broad ranging project took a subproject approach to examine several issues that ultimately relate to product yield and quality attributes of farmed Yellowtail Kingfish (YTK) grown in sea cages. Within this project, the performance (survival and growth) of fish stocked into sea cages was assessed in regards to (a) fish size and water temperature at the time of transfer to the sea, and (b) environmental conditions (i.e. water temperature and dissolved oxygen levels) during grow out.