1. POMS – The Latest R&D Results
Shellfish Futures, Adventure Bay, Tasmania. 2 October 2013
2. Pacific Oyster Mortality Syndrome POMS
Ostreid herpesvirus (OsHV-1uvar)
France 2007-8
New Zealand 2010
Georges River 2010
Sydney Harbour 2011
Hawkesbury River 2013
3. Mooney
Marra
Mullet Ck
Coba
Porto
DAY 0:
DAY 1:
DAY 3:
DAY 8:
First sighting (30% mortality on one lease)
By afternoon mass mortality
10 million dead oysters
Entire system affected
4. The R&D Response
1. Genetic selection for resistance
2. Develop a laboratory infection model system
3. Epidemiology and husbandry practices to
reduce economic losses
5. Three things you need to know
about breeding for resistance to
Pacific oyster mortality syndrome
Peter Kube (CSIRO)
Mike Dove (NSW DPI)
Matthew Cunningham (ASI)
Paul Hick (NSW DPI)
Wayne O’Connor (NSW DPI)
Peter Kirkland (NSW DPI)
Nick Elliott (CSIRO)
6. POINT #1:
There is good genetic variation
for POMS resistance
in our population
25. A laboratory model for infection
of Pacific oysters with Ostried
herpesvirus type-1 (OsHV-1)
Paul Hick, Mike Dove, Wayne O’Connor,
Xingnian Gu, Andrew Read, Peter Kirkland
27. GOAL: Develop procedures to infect oysters with OsHV-1
• OsHV-1 has been isolated from
oyster tissues (original Georges R
outbreak)
• Used to infect disease free oysters
• Developed procedures for long
term storage (including cryopreservation)
• Ongoing use of the same, well
characterised isolate is possible
28. Successful infection of spat by immersion
•
•
•
Adding virus to water was sufficient to infect and kill spat
(effective in 3 separate trials including with cryopreserved OsHV-1)
Variable results for juveniles and work is ongoing
Work has started on a challenge for larvae
Immersion challenges preferred because:
•
closer to natural infection compared to injection
•
Only practical way of managing large numbers of individuals
29. Ongoing work:
– Determine long-term stability of cryopreserved OsHV-1
– Define difference in susceptibility with age more closely
– Assess repeatability of laboratory infection model
– Apply laboratory challenge in genetic resistance project
30. Husbandry practices to reduce OsHV-1
mortality of Pacific oysters Crassostrea gigas
First steps towards integrated management
within an infected estuary
Ika Paul-Pont, Olivia Evans, Navneet Dhand, Ana
Rubio, Richard Whittington
Faculty of Veterinary Science – The University of Sydney
31. Field trials – Georges River
Height experiment in trays: summers 2011/2012
2012/2013
Standard
growing height
Better survival?
Immersion time
Exposure to virus
Higher
growing height
+300mm
Woolooware Bay, Georges River, NSW
> Triploid PO 11-12 month old:
Reduction of mortality by 25-50%
Maximum mortality at high height : 30-50%
> Triploid PO 2-7 month old:
No significant reduction of mortality
Low
Cumulative mortality (%)
Results:
50%
High
32. Window of infection – Georges and Hawkesbury Rivers
Every two weeks:
12 000 spat deployed at 8 sites
Spat collected, replaced by a new batch
Growth/mortality rates + PCR testing for OsHV-1 (n=30-100 spat per site)
Botany Bay - Georges River
2011/2012: November – May
2012/2013: November – May
Site A
Broken Bay - Hawkesbury River
2012/2013: January – May
Marra Marra
Creek
Mullet Creek
Site B
Site C
Patonga
Kimmerikong
Porto Bay
33. Safe spat experiment - 2013
March 2013: Land based experiment installed on-shore adjacent to the Hawkesbury River
Development of safe rearing techniques (farmers and hatcheries)
Specific water treatments to prevent disease occurrence
Co-funding: Tasmanian Oyster Research Committee
n=2000 spat/treatment
Flow rate= 5L/min/tank
No food supply
Daily sampling / mortality check
34. Safe spat experiment - 2013
Mortality
100%
Control (107 –109 viral DNA copies/g)
Sampling collection (n=40 per treatment)
and PCR testing
Cumulative mortality (%)
River (104 –108 viral DNA copies/g)
80%
60%
Chiller (107 –108 viral DNA copies/g)
40%
Sedimentation
20%
No virus detected
UV+filtration
No virus detected
0%
6-Apr
10-Apr
14-Apr
18-Apr
22-Apr Date
26-Apr
30-Apr
4-May
8-May
12-May
Conclusions:
- water treatments and land based system allowed spat survival in an infected estuary
- the role of UV and filtration remains unclear and need to be tested separately
- the 48h sedimentation provided the best outcome (cheap, easy) but needs to be confirmed
35. What can R&D deliver
in the medium term?
1. A medium term solution is expected from a combination of
resistant stock and changed husbandry practices
2. A laboratory infectivity model will be available and will be an
essential tool for breeding, and other, work
3. Useful levels of resistance are expected in juveniles by mid
2016 (three more years of selection)
4. Given the time required for commercial scale-up, this stock
won’t be available until 2018 at the earliest (as diploid)
36. Project Staff and Acknowledgements
NSW DPI
Mike Dove
Paul Hick
Peter Kirkland
Wayne O’Connor
Xingnian Gu
Andrew Read
FUNDING ASSISTANCE
Oysters Australia
Seafood CRC
FRDC
CSIRO
Peter Kube
Nick Elliott
ASI
Matthew Cunningham
University of Sydney
Ika Paul-Pont
Olivia Evans
Navneet Dhand
Ana Rubio
Richard Whittington
FIELD SITE (Georges River)
Drakes Oysters
