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south australian pacific oyster mortality trials

BUDGET EXPENDITURE: $481,700

PRINCIPLE INVESTIGATOR: Henry Hewish

ORGANISATION: Australian Seafood Industries (ASI)

PROJECT CODE: 2020-064

PROJECT STATUS: Current

 

WHY IS THIS RESEARCH BEING UNDERTAKEN: 

Australian Seafood industries (ASI) is an industry owned company which manages the Pacific Oyster 
breeding program for the Australian industry. The primary task of ASI in recent years years has been to 
breed oysters that are resistant to the disease POMS. While POMS caused devastation in Tasmania and 
South Australia, the impact differed in each state. Consequently, ASI¶s response has been different in each 
state.


In Tasmania, where ASI's principal hatchery is located, the disease caused high mortality consistently each 
year from its first occurrence in 2016 until last year when mortalities were minimal because most farms used 
ASI POMS resistant stock. ASI was able to rapidly breed for POMS resistance in Tasmania because it was 
possible to reliably challenge each new generation by natural infection. Commercial hatcheries in Tasmania 
were able to distribute POMS resistant stock to farms throughout Tasmania.


In South Australia, POMS disease has not occurred in oyster growing areas. However, the main suppliers of 
spat to SA farms were the two commercial hatcheries in Tasmania. Biosecurity controls implemented by the 
SA government precluded shipment of genetically improved spat from the Tasmanian hatcheries. To overcome this problem ASI and commercial hatcheries moved to establish breeding capacity in SA. In conjunction with SARDI, selection for POMS resistance was carried out using ASI oyster families that had been admitted to SA prior to the implementation of biosecurity border controls. While some progress was made in each generation, the rate of genetic improvement was slower than in Tasmania because it was not possible to effectively challenge the ASI families in SA with POMS. In an attempt to overcome this problem, the South Australian growers recently voted in favour of importing POMS resistant germplasm from Tasmania.


The decision for ASI to focus on POMS resistance in SA was made in conjunction with the industry. It was the 
logical approach at the time when it appeared to be highly likely that the disease would spread from 
Tasmania to SA. However, in the absence of POMS, SA growers have had to contend with widespread oyster 
mortality of unknown cause.


Over recent years ASI has collected some data on mortality in SA. Dr Peter Kube from CSIRO recently 
analysed the ASI data found that mortality may have a heritability greater than 0.2, which is adequate for a 
selection program.

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Against this background, ASI's South Australian shareholder, SAOGA, has made it clear that ASI must 
accelerate selection for SA survival in oysters while also increasing POMS resistance.


Since it is uncertain when POMS resistant germplasm will be imported into SA, the selection for SAMS 
resistance will need to be started on ASI oyster families already in SA. Tasmanian families will be integrated 
into the program when they become available.
 

Selection for SAMS will require extensive research to design and conduct field trials that are statistically valid 
and therefore useful for calculating EBVs. ASI does not have any staff in SA that can carry out this work and requires funding to appoint a project officer to be located in SA for a period of three years. The project is likely to have implications for other oyster growing jurisdictions which may be impacted in the 
future as a result of the environmental change.

 

OBJECTIVES:

  1. To increase the rate of genetic gains for SA survival.

  2. To investigate the relationship between environmental data and mortalities.

  3. To use the data generated from this project to inform ASI and commercial breeding decisions.

  4. To develop industry agreed medium/long term breeding targets for SA survival.

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RESOURCES GENERATED:

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