49 results

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

Project number: 2014-040
Project Status:
Completed
Budget expenditure: $463,700.00
Principal Investigator: Paul Hick
Organisation: University of Sydney (USYD)
Project start/end date: 30 Jun 2015 - 30 Jan 2018
:
TAGS
Stock Assessment
Mortality
Environmental Impact
Electronic Monitoring
Disease
SPECIES
Pacific Oyster

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

Final report

ISBN: 978-1-74210-445-4
Authors: Paul Hick Richard Whittington Olivia Evans Navneet Dhand Ana Rubio
Final Report • 2019-06-01 • 6.04 MB
2014-040-DLD.pdf

Summary

The present project is part of a continued program of epidemiologic investigations of OsHV-1 in Australia. Sufficient understanding of POMS is required to provide information for farmers and to direct policy so that profitable farming can continue despite increasing distribution and devastating impacts of OsHV-1. Observational studies of outbreaks have again identified risk factors for mortality that have been followed up with controlled experiments to determine how these can be exploited by farmers to minimise disease impacts. The present research provides a firmer understanding of the risk factors for disease through sentinel oyster surveillance and a combination of controlled field and laboratory experiments. Although a largely unpredictable disease some key risk factors are highlighted and predictions of the temporal and geographic distribution of OsHV1transmission has enabled successful window farming. The water temperature proxy for POMS risk enables modelling of the impact of OsHV-1 if the distribution continues to expand. The highly clustered nature of the disease on fine and larger geographic and temporal scales is illustrated in this research. The highly specialised nature of OsHV- transmission inferred is the key to better prediction of the disease in farming and continued research. Further work is required to understand the host factors that impact disease severity, particularly the role of prior exposure and the physiologic and metabolic status at the time of challenge. An insight into variation in genotype and phenotype of OsHV-1 isolates reinforces the need to consider the pathogen in predicting disease outcomes. Less virulent strains of OsHV-1 might lead naturally to reduced disease impacts in the future. 
Environment
Environment
PROJECT NUMBER • 2015-001
PROJECT STATUS:
COMPLETED

Aquatic Animal Health Subprogram: Bonamiasis in farmed Native Oysters (Ostrea angasi)

This project was a collaborative study across three research organisations: Agriculture Victoria, CSIRO (Victoria) and the South Australian Research and Development Institute (SARDI). The overall aim of this collaborative project was to better understand many aspects of infection with the parasite...
ORGANISATION:
Agriculture Victoria
TAGS
Toxin
SPECIES
Native Oyster
Environment

Future oysters CRC-P: Advanced understanding of POMS to guide farm management decisions in Tasmania

Project number: 2016-804
Project Status:
Completed
Budget expenditure: $694,773.00
Principal Investigator: Christine D. Crawford
Organisation: University of Tasmania (UTAS)
Project start/end date: 2 Jan 2017 - 29 Jun 2019
:
SPECIES
Pacific Oyster

Need

The OsHv-1 virus was first detected in Tasmanian oysters in January 2016 with massive mortality of oysters on farms in several major oyster growing areas, including Pittwater, Pipeclay Lagoon, Blackman Bay and Little Swanport. In other regions such as Bruny Island and Great Swanport the virus was found in oysters but mortalities were low. Reasons for these differences between oyster growing areas are unknown and there is an urgent need for Tasmanian oyster farmers to have region and site specific information on the period of infection of the virus in Tasmania and to better understand the POMS virus dynamics, leading to the development of a predictive framework and early warning for oyster farmers of POMS disease outbreaks. Oyster farmers in Tasmania also desperately need support to develop farm management techniques that enable them to operate successfully in POMS infected areas, especially during the next few years while selective breeding for POMS resistance is being developed.

Objectives

1. To determine i) the periodicity of infection of OsHV-1 virus in Tasmania, ii) advance the understanding of the drivers of POMS disease outbreaks, and iii) develop a predictive framework that allows the Tasmanian oyster industry to forecast danger periods for POMS.
2. To develop farm husbandry and handling protocols to maximise oyster production in POMS infected growing areas by investigating oyster survival in relation to: i) subtidal versus intertidal culture, ii) high water flow areas compared with low flow, iii) reduced handling, iv) size and timing of spat onto growout farms, and v) stocking density.
3. To enhance commercial production of Pacific oysters in a POMS infected area through analysis of past farm production and management records, and a contemporary study of farm production systems and oyster survival.

Final report

ISBN: Print: 978-1-922352-09-5 Electronic: 978-1-922352-10-1
Authors: Christine Crawford Sarah Ugalde
Final Report • 2019-08-01 • 4.07 MB
2016-804-DLD.pdf

Summary

The objectives of our research have been to determine the high-risk periods for POMS infection and to develop a predictive framework so that the farmers can forecast danger periods for POMS. This includes developing a better understanding of where the virus exists in the environment and the factors that drive POMS disease outbreaks. We also aimed to work with the oyster industry to develop farm husbandry and handling protocols that maximise oyster production in POMS infected growing areas. Additionally, we surveyed the oyster farmers affected by POMS to get an overall view of the impact of POMS, especially socio-economic aspects.
 
Our research supports other studies that warm water temperature is a major driver of POMS outbreaks, with temperatures in south-eastern Tasmanian growing areas of 19 °C and above for around one week providing a high risk for a disease event to occur. The risk period for POMS disease outbreaks ranges from mid-November to late March. Other environmental factors likely to be important include water movements and density of infected oysters in a water body. Growing areas with extensive intertidal flats and poor water circulation, such as Pittwater, or with a high biomass of farmed and feral oysters in a relatively small area, such as Pipe Clay Lagoon, have shown to be more susceptible to POMS disease than the other farming areas. As feral oysters in Pipe Clay had a relatively high prevalence of OsHV-1, they may be contributing to the reservoir host of the virus.
 
Studies on farming practices conducted in close collaboration with oyster growers suggest that density of oysters in culture containers has limited effect on mortality rates, and that some
handling is required during the POMS season to reduce biofouling and maintain stocking densities conducive to good growth and survival. Younger and smaller oysters are more susceptible to infection that larger and older juvenile and adult oysters. For oysters of the same age cohort, fast growers had higher mortalities than slow growers.
 
The surveys of oyster growers on the impacts of POMS on their farming operations has shown that mortalities from POMS have rapidly declined from an average of 67% of stock in 2016 to 9% in 2018/19. Changes to farming practices that have occurred during this time include a large increase in stock selectively bred for POMS disease resistance, reduced and more careful handling of oysters during the summer POMS season, selling a higher percentage of stock before the POMS high risk period, and purchasing spat when temperatures are declining.
Industry
PROJECT NUMBER • 2013-708
PROJECT STATUS:
COMPLETED

Seafood CRC: safe spat rearing experiment

The production cycle of Pacific Oysters in Australia currently depends on hatchery production of spat, mainly in Tasmania. Experience in France and other European countries is that OsHV-1 affects mainly hatchery spat and juvenile oysters, with near total losses of affected batches being common....
ORGANISATION:
Oysters Australia Ltd
TAGS
Mortality
SPECIES
Pacific Oyster
Industry
Industry
PROJECT NUMBER • 2019-208
PROJECT STATUS:
COMPLETED

2020-2025 Strategic Plan for the Australian Oyster Industry

The primary purpose of this plan is to coordinate oyster industry research, development, and extension (RD&E) across Australia to ensure that usable outputs are provided to oyster businesses. The plan outlines a set of RD&E programs and a list of priority projects for which research...
ORGANISATION:
Oysters Australia Ltd
TAGS
Disease
SPECIES
Sydney Rock Oyster
Industry
PROJECT NUMBER • 2016-800
PROJECT STATUS:
COMPLETED

Future Oysters CRC-P Management and Extension

The Future Oysters CRC-P project (CRC-P 2016-553805; Future Oysters) was funded by the Australian Government’s Business Cooperative Research Centres (CRC) Program, which is managed by the Department of Industry, Innovation and Science (DIIS). The Future Oysters CRC-P project was developed to...
ORGANISATION:
Australian Seafood Industries Pty Ltd (ASI)
TAGS
Mortality
SPECIES
Sydney Rock Oyster
Environment
PROJECT NUMBER • 2016-245
PROJECT STATUS:
COMPLETED

Development of sector-specific biosecurity plan templates and guidance documents for the abalone and oyster aquaculture industries

This project developed industry endorsed biosecurity plans and guidance documents for the abalone farming industry (land based), and Oyster hatcheries. These documents provide industry with detailed guidance to develop a new, or improve existing, farm biosecurity plans and supporting...
ORGANISATION:
Department of Primary Industries and Regions South Australia (PIRSA)
TAGS
Husbandry
SPECIES
Tropical Abalone
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