SCRC: Yellowtail Kingfish genetics: commercialisation strategies
Clean Seas Tuna are now focusing on YTK and genetics is a key to enhancing the commercial success of YTK production. Not only will a successful genetics program lead to improvements in the quality of the fish and profitability of the program, it will also open an opportunity for the sale of genetically improved seed both nationally and internationally. For a successful and enduring YTK genetics program we need:
1. To use the genetic program to promote the CST business of fingerling sales nationally and internationally.
Over the last few years, CST has sold YTK fingerlings to overseas buyers. This market is embryonic
and its full potential not explored. As a unique holder of genetically selected stock which is raised in
pristine conditions, CST are interested to explore how the genetically selected stocks can be used to
promote international sales of YTK fingerlings. The following are needed to support this ambition:
1.1 Documentation of the production and commercial value of the genetically improved stocks locally
and overseas via international collaborations
1.2 The design and production of publicity materials (websites/ brochures) explaining the genetic
program and its value
1.3 The design of genetic protection to ensure fingerlings sold are used for grow out and are not suitable to be used as elite broodstock elsewhere
2. Fully Integrate the genetic program with industry operations:
The present YTK genetic project currently operates with specialist and ongoing input from broodstock biologists, genotypers, quantitative genetics and project leaders. While web resources have been put in place to handle the flow and interconnection of the information and data, these arrangements were better suited for the development of a genetic program rather than its long term operations integrated with industry. There is a need to develop a raft of support materials, such as plans, data storage, and data analysis tools to permit the genetic program to operate smoothly within the industry environment. There is potential to integrate this component of the work with legacy project 2012/757 if the latter should go ahead
3. Ensuring the genetic program attains international best practice in rate of genetic improvement
We can enhance the present YTK genetic program in terms of dividend per year:
3.1 Presently, CST have been using 4-5 year old female YTK to spawn which substantially retards the rate of
genetic response per year (modelling shows contracting generation time is the most effective way to
accelerate yearly genetic gain). Therefore there is a need to develop the technologies to shorten the
generation time to speed up per year selection response
3.2 Optimize selection response while minimizing inbreeding
3.3 Maximize the accuracy of selection (using information from relatives and genomic information)
4. Capture and sustain genetic diversity in the long term
The initial economic and production imperative was to move CST YTK to all production based on selected F1 or F2 animals. This was achieved in project 2010/768 and while this project met the go / no go requirement of an effective population size of 40 (limiting long term inbreeding to about 1%) , there are insufficient families being produced to do much between family selection (culling of whole poor families).
4.1 CST only has sufficient families to permit within family selection. 16 males and 17 females have contributed to the next generation, and while there are dozens of different families, the effective population size is fractionally low to sustain inbreeding rate of less than 1%, adding and keeping the equivalent of five families will bring the long term inbreeding rates to below 1%. This will also help promote the long term sustainability of the genetic program in terms of inbreeding and maintaining genetic diversity. In addition, we will introduce advanced statistical tools such as optimal genetic contribution theory to maximize genetic gain while minimizing inbreeding to sustain genetic progress in kingfish.
Final report
Previously, we have implemented a selective breeding program for Yellowtail Kingfish (YTK) and today all production is based on genetically selected stock, which is up to 20% superior than the wild stock.
This current project focuses on whether realized selection response was achieved and adds:
- further families to the pedigree
- facilities (broodstock tanks) to the program
- data management and long term planning
- new DNA microsatellite markers for pedigree assignment
- measures the genetic improvement at up to 20%
Today, CST is the only kingfish production company with a genetic program that has progressed beyond breeding the first generation yet maintained diversity. Present CST is in the unique position of having well advanced F2s and soon will have F3s in production.
We have produced recombinant FSH and demonstrated it acts to promote gonadal development in YTK
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SCRC: Development of Yellowtail Kingfish aquaculture in Western Australia: Removal of barriers to profitable production.
If the Midwest is to achieve its potential of 40,000 tonnes of annual finfish production in the longer term it initially needs incremental development. At the moment it is surrounded by large risks. In order to progress, some of these risks need to be fully identified and then removed, reduced, managed or mitigated. This project is needed to address the removal of those barriers to commercial development that have been identified during the current MFA project (eg parasites) and optimising some key inputs (larval and genetics) to production to improve the commercial viability of a larger scale industry
There is a need for a genetic management strategy to ensure that the captive broodstock comprise a genetically diverse population in order to avoid inbreeding and to provide good opportunities for future genetic selection. There is also the need to more fully understand what genetic variation exists in wild yellowtail kingfish from within WA to both ensure that broodstock populations are representative of this diversity and to make management decisions regarding integration into national breeding programs.
High incidences of malformations continue to impact heavily on the price of juvenile kingfish. There is a need therefore, to reduce the incidence of such malformations to reduce the cost of juvenile production and improve the quality of fish being put to sea.
Sea-caged yellowtail kingfish in Western Australia have a high prevalence of the myxozoan parasite Unicapsula seriolae. It has been recorded in the Jurien Bay fish in 2008/9 and has been monitored closely from development in the current MFA yellowtail kingfish project. This parasite results in myoliquefaction in the same species of fish in Queensland. Its impact on a potential yellowtail kingfish commercial aquaculture industry in WA needs to be assessed and management practices developed and implemented to reduce its impact.
Final report
Sub-Project 1: Genetics
DNA analyses were used to develop a mating strategy to avoid inbreeding among the limited number of existing captive broodstock in WA. A genetic management workshop was carried out in with ACAAR and WA Industry and used to inform attendees about basic genetic management principles and to collect information relevant to the formulation of the strategy. A genetic management database for tracking fish, collection of water quality data, recording treatments, pedigrees, relatedness and fish traits was developed and tested. The same database has been further enhanced and rolled out to ACAAR and two barramundi hatcheries (Project 2009/730) offering a simple but effective genetic management tool for both of these species.
Sub-Project 2: Larviculture
Our study comparing different rotifer feeding strategies demonstrated that up to 65% fewer rotifers can be used in the production of juvenile YTK than are currently being used in commercial hatcheries, without any negative impact on growth or survival. This is the result of efficient prey capture at low prey densities, even from a young age. This reduction in rotifer usage translates directly to the same percentage reduction in rotifer operating costs. We were unable to determine whether these different strategies had an effect on larval malformation rates, due to the small size of the larvae at the end of the rotifer feeding phase. The results of this research are now being implemented at ACAAR and a manuscript describing this research has been submitted to the ISI Journal, Aquaculture Research. Detailed biochemical composition analyses were performed on rotifers and Artemia enriched on various diets and a blend of diets used in the commercial hatchery production of cobia. These analyses revealed some significant differences in certain aspects of the nutritional composition of both live feed types.