Project number: 2012-032
Project Status:
Completed
Budget expenditure: $783,045.00
Principal Investigator: Richard Whittington
Organisation: University of Sydney (USYD)
Project start/end date: 18 Jun 2012 - 6 Sep 2015
Contact:
FRDC

Need

There is a disturbing pattern of diseases in commercial molluscs nationally. They have required a succession of government/industry responses, with no clear solutions:QX disease, Sydney rock oysters, NSW and QLD; NSW; Pacific oyster mortality syndrome, NSW; Abalone viral ganglioneuritis, VIC; Oyster oedema disease, pearl oysters, WA; Winter mortality, Sydney rock oyster, NSW.

Economic impacts have been substantial or devastating. Wild fisheries and aquaculture have been impacted. In NSW, the primary impact of QX disease led to replacement of Sydney rock oysters by triploid Pacific oysters to reestablish the industry in some estuaries, but this is now threatened by POMS.

In every case the new disease has spread. It has not been possible to devise an intervention strategy that would halt disease spread or ensure the recovery of the industry. Investigating the behaviour of POMS during its recrudescence in summer 2011/2012 in FRDC project 2011-053 afforded a unique insight into the disease, and these observations need to be extended over time to identify factors which may be used to reduce the impact of the infection.

This project seeks to address 6 specific research priorities identified by FRDC and will concurrently investigate the effect of host, environment and husbandry factors on POMS prevalence and mortality rate in Pacific oysters with the objective of discovering aspects of epidemiology which can be manipulated by oyster growers. If POMS spreads beyond its current limited distribution in NSW, commercial scale production of Pacific oysters in the face of POMS will be essential for the viability of the industry pending development of technical solutions such as genetically resistant lines.

FRDC strategic R&D theme 1 - biosecurity and aquatic animal health, and Aquatic Animal Health Subprogram priority - Nature of disease and host-pathogen interaction - immunology of aquatic invertebrates.

Objectives

1. To determine/confirm the identity of the one or more variant(s) of Ostreid herpesvirus associated with the recent outbreaks of POMS
2. To determine the mechanism(s) of transmission of disease
3. To determine the major risk factors that contribute to precipitation of disease outbreaks thereby identifying potential risk-mitigation management practices
4. To identify the natural reservoir(s) for the virus
5. To determine the stability of the virus in the environment
6. To identify physical and chemical means for viral inactivation
7. To develop an infecitivity model for POMS suitable for selection of resistant oysters and pathogenesis/environmental research
8. To address future shortages of technical expertise through the training and supervision of at least 1 PhD student
Final Report • 2015-12-11

Summary

Abstract:

Mortality of farmed triploid Pacific oysters (Crassostrea gigas) associated with Ostreid herpesvirus-1 (OsHV-1) was first recorded in Australia in the Georges River/Botany Bay estuary (New South Wales) in late 2010. Two years later, the first sign of possible inter-estuarine spread was observed when commercial triploid Pacific oysters in the Hawkesbury River estuary, located 50 km north of Botany Bay, were affected by mass mortality.

Final Report • 2015-12-11

Summary

Abstract:

In Australia, the spread of the ostreid herpesvirus-1 microvariant (OsHV-1 μVar) threatens the Pacific oyster industry. There is an urgent need to develop an experimental infection model in order to study the pathogenesis of the virus under controlled laboratory conditions. The present study constitutes the first attempt to use archived frozen oysters as a source of inoculum, based on the Australian OsHV-1μVar strain.

Final Report • 2015-12-11

Summary

Abstract:

 

The microvariant genotype of Ostreid herpesvirus-1 (OsHV-1 μVar) has severely disrupted the production of Pacific oysters Crassostrea gigas in Europe, New Zealand, and Australia since its first detection in France in 2008. The disease occurs in the warmer months, recurs annually, and requires new management strategies. Larvae and spat are the most susceptible life history stages, which poses a threat to hatchery production.

 

Final Report • 2015-12-11

Summary

Abstract:

Management of mass mortality events associated with Ostreid herpesvirus-1 microvariant (OsHV-1 μVar) is vital for aquaculture of Crassostrea gigas. As a consequence, the understanding of transmission mechanisms and risk factors enabling husbandry solutions to be developed constitutes an international research priority. In this context, a longitudinal intervention study was set up in Woolooware Bay, Australia, during summer in 2012–2013.

Final Report • 2015-12-11

Summary

Abstract:

In 2010 Ostreid herpesvirus-1 (OsHV-1) was detected in Australia and had a disastrous impact on Pacific oyster Crassostrea gigas aquaculture and coastal communities. The acronym POMS (Pacific Oyster Mortality Syndrome) was created in Australia to refer to mass mortalities due to OsHV-1. While management of this disease mainly involves active surveillance, rigorous biosecurity protocols and mollusc breeding  programs targeting production of resistant animals, the effects of aquaculture practices on mortality outbreaks are still poorly understood. The present study aimed to determine the effect of growing heights on OsHV-1 associated mortality in C. gigas in Woolooware Bay (Australia) during the summer 2011/2012.

Final Report • 2015-12-11

Summary

Abstract:

Ostreid herpesvirus-1 (OsHV-1) is responsible for massive mortality events in commercially farmed Pacific oysters (Crassostrea gigas) in Australia, New Zealand, Europe and the USA. Economic losses have been severe in many countries since 2008, associated with a strain known as OsHV-1µ-var. Despite intensive studies of the virus itself, there is almost no information on its detection in natural seawater, how it is spread over wide geographic distance in water or on how it is transmitted from oyster to oyster via seawater.

Related research

Industry
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PROJECT NUMBER • 2019-210
PROJECT STATUS:
COMPLETED

Oyster Industry Response to the COVID19 Crisis

1. To prepare a brief to governments and industry describing the most useful activities that could be carried out to support improved oyster sales across the whole industry .
ORGANISATION:
Oysters Australia Ltd
Industry