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Title:

Oysters Australia IPA: Pacific Oyster Mortality Syndrome (POMS) – closing knowledge gaps to continue farming C. gigas in Australia

Project Number:

2014-040

Organisation:

University of Sydney (USYD)

Principal Investigator:

Paul Hick

Project Status:

Current

FRDC Expenditure:

$463,700.00

Program(s):

Environment

Need

POMS, caused by OsHV-1, has devastated C. gigas farming in two estuaries in NSW. Australia’s other growing areas are free (survey 2011). Expert opinion is that the virus will spread, but the time frame is unpredictable; TAS and SA are at great risk. Research to find a solution to continue farming is an immediate priority to protect the ~$53M pa industry. Farming C. gigas in the face of POMS requires improvements in both husbandry and genetics. Genetically resistant stock will not be available commercially until 2018, with partial resistance (POMS R&D Coordination Committee report). Improved husbandry is needed at all stages of the production cycle. It is addressed by this application, which builds on research in FRDC projects 2011/053 and 2012/032 that led to breakthroughs in understanding the epidemiology of POMS: mortality can be completely prevented in hatcheries using relatively simple water treatments, and reduced by 50% in adult stock (but not juveniles) by raising the growing height. However, many growers do not have infrastructure for this. In June 2014 industry stated it would benefit from information about consistency of seasonal infection, changes in the virus, hatchery biosecurity, and whether spat can be certified free from infection. Growers at SAOGA August 2014 reiterated that they urgently need a strategy for juvenile grow out and rack and rail systems that can't easily be elevated. Priorities were confirmed in a face to face meeting with TORC members on 28th August 2014. Objectives were reviewed by Oysters Australia R&D committee on 1/12/14, and modified accordingly, leading to this full application. This project fits within the FRDC 2015 Environment Priority 5: development of robust methodologies for investigation of mollusk disease outbreaks; integrated health management for commercial molluscs, which flow from priorities of the Aquatic Animal Health Subprogram.

Objectives

1. To determine methods for the conditioning/husbandry of spat and juvenile oysters to obtain survival after exposure to OsHV-1 based on improved scientific understanding of exposure, pathogenesis, immunity, tolerance or latency

2. To confirm i) the consistency of seasonal patterns of POMS, ii) the periodicity of infection within season, iii) inter-estuary temperature variation, and iv) predict POMS seasonal behaviour.

3. To identify changes in OsHV-1 DNA sequence over time (2010-2016) to understand infection and disease patterns

4. To investigate the mechanisms of survival of Pacific oysters after exposure to OsHV-1, including assessment of exposure dose and using biosensors

5. To determine whether water treatments prevent OsHV-1 infection of spat or merely prevent mortality, and whether they can be applied for biosecurity of hatchery effluent

6. To describe an integrated disease control strategy based on complementary use of genetically resistant oysters (when available) and husbandry methods throughout the production cycle: hatchery-juvenile-growout to market

7. To build capacity in aquatic animal health for Australian industry through training a post graduate student