The document discusses research on Pacific Oyster Mortality Syndrome (POMS) in Australia. It provides background on POMS in Europe and describes the Australian situation. Key points made include: - POMS is caused by a mutant strain of Ostreid Herpesvirus-1 (OsHV-1) - In Europe, it first emerged in 2008 and caused mass mortality in larvae and spat (juveniles under 18 months) - In Australia, outbreaks began in 2010 in New South Wales and caused complete abandonment of some farming areas - Research is focusing on identifying factors that drive the disease and how to continue farming around it, including safe spat rearing methods, monitoring windows of infection, and breeding

1. Pacific oyster mortality syndrome
(POMS)
First steps towards integrated management
within infected estuaries
Richard Whittington, Paul Hick, Olivia Evans,
Navneet Dhand, Ana Rubio & Ika Paul-Pont
Faculty of Veterinary Science - University of Sydney
Oysters Tasmania meeting Smithton 18th October 2014

2. The plan
1. POMS in Europe
2. Australian POMS situation
3. Research
– from spat rearing to on-farm grow-out,
– priorities to plug remaining gaps
– how this links to the POMS breeding program
4. Request for farmers to help collect data

3. 1. POMS in Europe

4. History of POMS
“Summer mortality” in Pacific oysters
Country Year Age group Mortality Cause
Japan 1960’s adult variable unknown
USA 1980’s all variable unknown
France 1980’s young variable OsHV-1
OsHV-1 occurs in USA, Japan, and some European countries, without mass mortality

5. “Summer mortality” in Pacific oysters
Country Year Age group Mortality Cause
Japan 1960’s adult variable unknown
USA 1980’s juvenile variable unknown
France 1980’s juvenile variable OsHV-1
France 2008 larvae, spat massive OsHV-1 microvar
UK, Ireland, Spain >2008 larvae, spat massive OsHV-1 microvar
New Zealand April 2010 spat and adult massive OsHV-1 microvar
OsHV-1 occurs in USA, Japan, and some European countries, without mass mortality

6. What is OsHV-1 uvar?
• It is a marine herpesvirus
• not related to human herpesvirus
• cannot infect warm blooded animals
• no risk to human health
• There are two important marine herpesviruses
• abalone herpesvirus
• ostreid herpesvirus
– OsHV-1 reference strain – the original strain
– OsHV-1 microvar (uvar) – a new mutant strain

7. Oysters in France
Baie de Archachon
August 2012

8. The French experience

9. Impact of POMS in France since 2008
Response
1. big players produce 10x more spat and
grow the 10% that survive
2. market price has increased
3. focus is on a breeding program
– private hatcheries, mass selection
– government program, selection based
on lab challenge with OsHV-1 and
three species of vibrio
50% of the industry has been lost,
especially small farmers
government compensation exists
incentive to reduce losses?

10. “Summer mortality”
Larvae < 1 month:
all dead
Spat / Juvenile <18 months:
>90% dead
Adults > 18 months:
10-40% dead
whoi.edu
POMS behaviour in Europe

11. Seasonal pattern of OsHV-1 μvar
France
since 2008
2009 – Disease progresses from south to north in summer as water temperatures increases

12. French research - IFREMER
• Breeding program
• POMS remains a huge issue in 2014, 6 years
after it emerged and despite millions of Euros
spent in research
• Research will be ongoing
Dr Tristan Renault

13. 2. Australian POMS situation

14. Port Jackson
– Sydney Harbour
Nov 2010
Botany Bay
– Georges River
Nov 2010
50
0
km
POMS in Australia 2010 to 2013
Broken Bay
– Hawkesbury River
Jan 2013
Commercial
production
abandoned

16. Hawkesbury - Sequence of events 2013
Day 1 - 21st Jan
• 10 am – first mortality in spat
• 5 pm - mass mortality event
• 7pm - samples delivered to DPI
Day 2 - 22nd Jan
• Outbreak investigation commenced
• Broken Bay Oyster Association
– voluntary quarantine of river
– supported an outbreak investigation
• 7pm DPI lab confirmed POMS
Mullet Creek

17. Day 3 - 23rd Jan
• 10 million dead oysters
• $3 million loss locally
• $0.6 million hatchery loss
• Casual staff laid off
• Banks called in debt
Day 7- 28th Jan
• Businesses, boats, equipment sold
Day 8 – 29th Jan
• Minister visits affected oyster growers

18. Real time outbreak investigation
1. Passive surveillance to monitor spread
• farmer observations of mortality
2. Active surveillance
• identify risky oyster movements in last 2 weeks
• whole river survey to identify infected bays/leases
• detailed assessment of all dead stock
• water tests

19. 1st question. Where?
29 Jan
Broken Bay Oysters, Hornsby Shire Council, University of Sydney
Current as at 7 February
Index case
21 Jan
15 Feb
24 Jan
29 Jan
25 Jan

20. 2nd question. Who died?
Extreme mortality
Moderate to
high mortality

21. 3rd question. When?
Date Sites Sample size OsHV-1 qPCR
26-Oct-11 M,P 30 Negative
7-Dec-11 M,P 30 Negative
19-Dec-11 M,P 30 Negative
4-Jan-12 M,P 30 Negative
18-Jan-12 M,P,R,K 30 Negative
15-Feb-12 M,P,R,K 30 Negative
15-Mar-12 M,P 30 Negative
20-Apr-12 M,P 30 Negative
10-May-12 M,P 30 Negative
5-Jun-12 M,P,R,K 30 Negative
3-Aug-12 M,P,R,K 30 Negative
20-Sep-12 P 30 Negative
1-Oct-12 P 30 Negative
12-Oct-12 P 30 Negative
18-Oct-12 M 21 Inconclusive
19-Oct-12 P 30 Negative
26-Nov-12 M,P 30 Negative
13-Dec-12 M 30 Inconclusive
26-Dec-12 M,P 30 Negative
7-Jan-13 M,P 30 Inconclusive 4 Positive 1 M
21-Jan-13 M,P 30 Positive
2-Feb-13 P 30 Positive
15-Feb-13 P 30 Positive
26th Oct 11
18th Oct 12
3 months
21st Jan13
Sentinel oysters (6 pools of 5) each time

22. 4th question. How did it spread?
• Within the river system?
1. local oyster movements
• within 2 days of the onset of the outbreak (i.e. on or after Jan 19th)
• incubation period < 10 days (oysters moved 19th Jan died 29th Jan)
2. tide and current (16 km upstream tidal movement)
• To the Hawkesbury?
1. Oyster movements?
• no record of any, except certified OsHV-1 negative spat
2. Oceanic source?
• tiny amount of virus arrived October 2012
• massive dose arrived between 17th and 19th January 2013
– incubation period for mass mortality 2-4 days

23. Connectedness
US Navy 1943

24. Connectedness
Thirroul Beach NSW 2011
Driftwood carrying oyster shell Thirroul Beach NSW 2014
Pumice (origin New Caledonia)
carrying oyster spat

25. Connectedness

26. 3. Targeted research on POMS

27. Research objective –
“to continue farming around POMS”
• What factors drive the disease?
• Can we exploit them?
Breakthroughs needed for:
1. Hatchery production
2. Spat rearing
3. Growout –juveniles/adults

28. Broken Bay
Hawkesbury River
Control site until 2013
Botany Bay
Georges River
Infected since 2010
10 Km
New South Wales
SYDNEY
Bruce Alford – Broken Bay Oysters
Len Drake – Endeavour oysters
Research sites
POMS research sites

29. Georges River tray trials 2011-2012

30. Georges River tray trials 2011-2012
Spatial pattern:
Non uniform transmission
Uneven mortality
Percent mortality:
30
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
55 67
50 97
47 97
18 74
8 92
8 42
13 33
3 24

31. Georges River field trials 2011-2012 and 2012 2013
 OsHV-1 is not evenly distributed in water - it is attached to something
plankton vector hypothesis
A
November 2011
B
February 2012
C
It might be possible to get OsHV-1 out of
seawater
November 2011

32. Hatchery/Safe spat rearing trials 2013 and 2014
Co-funding: FRDC, University of Sydney, Tasmanian Oyster Research Committee,
Oysters Australia through Seafood CRC
n=2000 spat/treatment
Flow rate= 5L/min/tank
No food supply
Daily sampling / mortality check

33. 10,000 L holding
tanks
Submersible
pumps
Floating basket
with control spat

34. Safe spat rearing
500 spat
Filter + UV
Aged water
Control water
Filtered water
Trial 1 Trials 2-7

35. Daily filter clean
Daily spat examination

36. 0%
20%
40%
60%
80%
100%
30-Oct-13
31-Oct-13
1-Nov-13
2-Nov-13
3-Nov-13
4-Nov-13
5-Nov-13
6-Nov-13
7-Nov-13
8-Nov-13
9-Nov-13
10-Nov-13
11-Nov-13
12-Nov-13
13-Nov-13
14-Nov-13
15-Nov-13
16-Nov-13
17-Nov-13
18-Nov-13
19-Nov-13
20-Nov-13
21-Nov-13
22-Nov-13
23-Nov-13
24-Nov-13
25-Nov-13
26-Nov-13
Cumulative mortality
Date
2nd safe spat rearing trial - 30 Oct 2013
River control
Upweller control
Filter 100/5 μm
Aged water
Filter 100/5 μm + UV
Safe spat rearing trials 2013 and 2014

37. Hatchery-Safe spat rearing trials 2013 and 2014
Safe spat rearing:
Mortality %
• Age seawater for 48 hours before use, or
• Filter seawater to 5 micron

38. When is it safe to put spat in the
estuary?
• 500 spat placed at multiple sites
• every 2 weeks Aug 2013 to May 2014
• each lot checked 2 to 4 weeks later
• 21 lots all together
Olivia Evans PhD student

39. Georges River – Window of Infection
39
5 1 = Mangroves
1
2
3
4
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
6 = Site A
7= Site B
8 = Site C
C
A
B

40. 40
Mortality Data : Georges River
RESULTS:
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
August 2013
A
C
B

41. 41
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
September 2013
A
C
B
Mortality Data : Georges River

42. 42
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
October 2013
A
C
B
Mortality Data : Georges River

43. 43
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
November 2013
A
C
B
Mortality Data : Georges River

44. 44
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
December 2013
A
C
B
Mortality Data : Georges River

45. 45
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
January 2014
A
C
B
Mortality Data : Georges River

46. 46
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
February 2014
A
C
B
Mortality Data : Georges River

47. 47
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
March 2014
A
C
B
Mortality Data : Georges River

48. 48
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
April 2014
A
C
B
Mortality Data : Georges River

49. 49
5 Wild Sites:
1
2
3
4
1 = Oyster Shed
Mangroves
2 = Pelican Gut
3 = Sylvania Waters
4 = Never Fail Bay
5 = Lime Kiln Barr
Farmed Sites:
Site A
Site B
Site C
May 2014
A
C
B
Mortality Data : Georges River

50. Hawkesbury River – Window of Infection
50
1
2
3
4
5
1 = Patonga
2 = Porto Bay
3 = Mullet Creek
4 = Marra Marra
5 = Kimmerikong

51. RESULTS:
51
Mortality Data Window : Hawkesbury River
1
2
3
4
5
1 = Patonga
2 = Porto Bay
3 = Mullet Creek
4 = Marra Marra
5 = Kimmerikong
August 2013

52. 52
Mortality Data Window : Hawkesbury River
1
2
3
4
5
1 = Patonga
2 = Porto Bay
3 = Mullet Creek
4 = Marra Marra
5 = Kimmerikong
September 2013

53. 53
Mortality Data Window : Hawkesbury River
1
2
3
4
5
1 = Patonga
2 = Porto Bay
3 = Mullet Creek
4 = Marra Marra
5 = Kimmerikong
October 2013

54. 54
Mortality Data Window : Hawkesbury River
1
2
3
4
5
1 = Patonga
2 = Porto Bay
3 = Mullet Creek
4 = Marra Marra
5 = Kimmerikong
November 2013

55. 55
Mortality Data Window : Hawkesbury River
1
2
3
4
5
1 = Patonga
2 = Porto Bay
3 = Mullet Creek
4 = Marra Marra
5 = Kimmerikong
December 2013

56. 56
Mortality Data Window : Hawkesbury River
1
2
3
4
5
1 = Patonga
2 = Porto Bay
3 = Mullet Creek
4 = Marra Marra
5 = Kimmerikong
January 2014

57. 57
Mortality Data Window : Hawkesbury River
1
2
3
4
5
1 = Patonga
2 = Porto Bay
3 = Mullet Creek
4 = Marra Marra
5 = Kimmerikong
February 2014

58. 58
Mortality Data Window : Hawkesbury River
1
2
3
4
5
1 = Patonga
2 = Porto Bay
3 = Mullet Creek
4 = Marra Marra
5 = Kimmerikong
March – May
2014

59. Window of infection summary
RIVER First mortality Last mortality
Georges October 2013 April 2014
Hawkesbury October 2013 February 2014
59
• Risk of mortality is not constant throughout the season
• Risk is not the same in different bays or estuaries
• It is safe between May and September

60. What can you do to keep farming
during the risky window?
• Adults – partial solution
– Intertidal culture – raise growing height if you can
– Otherwise it is a research priority
• Spat – no solution yet
– Remains a research priority
November
May
October

61. 2 month old
7 month old
15 month old
Field trials 2011-2012 and 2012 2013
Rack and rail – trays
Long-line - baskets
Floating - baskets
7,600 - 18,000 oysters
3 ages/sizes
Every oyster examined
every 7 to 14 days

62. Adults and spat 2011-2012 and 2012 2013
Standard height
‘Low’
+300 mm
‘High’

63. Adults
Consistent findings were obtained at all 3 sites and in both summers
+300 mm high growing height
• mortality <50%
Cumulative mortality (%)
Low
High (+300mm)

64. Spat 2012-2013
• No benefit in raising growing height in either baskets or trays
• Same results in trays, hanging baskets and floating systems
• Spat are just too susceptible – most die
• This remains the biggest hurdle

65. Other important observations
• Oysters that survive an outbreak are “immune” and survive
the next outbreak
• OsHV-1 can be detected at a low level in some oysters more
than 1 month before an outbreak
– these are almost certainly the oysters that survive
– can we exploit this?
• Age and size – but which is more important?
• Temperature patterns for POMS

66. France: water temperature and disease

67. Georges River summer 2012-2013 Sites A, B, C
Average weekly water temperature
5.0
10.0
15.0
20.0
25.0
30.0
31/07/2012
7/08/2012
14/08/2012
21/08/2012
28/08/2012
4/09/2012
11/09/2012
18/09/2012
25/09/2012
2/10/2012
9/10/2012
16/10/2012
23/10/2012
30/10/2012
6/11/2012
13/11/2012
20/11/2012
27/11/2012
4/12/2012
11/12/2012
18/12/2012
25/12/2012
1/01/2013
8/01/2013
15/01/2013
22/01/2013
29/01/2013
5/02/2013
12/02/2013
19/02/2013
26/02/2013
5/03/2013
12/03/2013
19/03/2013
26/03/2013
2/04/2013
9/04/2013
16/04/2013
23/04/2013
30/04/2013
7/05/2013
14/05/2013
21/05/2013
2 month period Mortality in tray and baskets trials
without disease
that is not
explained by
French data
meantemp A
15oC
meantemp B
meantemp C
31 Jul
2012
Conclusions
1. we need to intepret water temperatures under Australian conditions
2. we need to standardise the way we measure water temperature
3. we may be able to predict risk periods
21 May
2013

68. Exploitable discoveries from research
1. Removal of virus from water
2. There is a safe window
3. Age and size are important
4. Survivors are “immune”
5. Growing height
• Safe spat rearing
• Normal cultivation possible
• Growout and fattening
This knowledge directly complements the POMS breeding program

69. Integrated approach
May-October: safe period
Novel cultivation practices from the hatchery
through to commercial harvest
1. Spat held in OsHV-1 free estuaries, or
2. Spat held in safe land-based systems
Spat - November-May: (year 1)
October
• Spat in the River
• Trial fast growing
cultivation systems
(FLUPSY)
1. Oysters that reach market size  sell
2. Other adult oysters  high height (<50% will die)
November
5 months
May
October
Adults - November-May (year 2)
Survivors are immune – grow
them at standard height
6 months
Safe spat rearing
market
Hatchery

70. Further research is needed now
Solve problem of spat culture during window of infection
Solve problem of grow-out for farmers who cannot raise growing height
Predict risk periods for Tasmania and South Australia
November
May
October
1. Exploit resistance due to age and size
2. Artificially condition spat to survive
3. Genetically resistant spat
November
May
October
Proposal to FRDC in current call for new projects

71. Species diversification
Sensitive/Resistant
Dilution effect
Cash flow
Biosecurity
Active surveillance
Quarantine protocols
Control of movements / transfers
Complementary
approaches
Farming practices
Husbandry techniques
Fast growing systems
Density
Selective breeding Research
Resistance PO
Other traits
Reliable supply
Timeframe
Epidemiology
Pathogenicity
Immunology
STRATEGIES
for POMS
Review business models particularly debt levels
to cope with sudden cessation of cash flow

72. 4. Request for help
• 10 farmers from different parts of Tasmania
• Temperature probes on oyster leases
• Duration – up to 3 years
• Inconvenience – a bit
• Benefit – knowledge about temperature
profiles relative to estuaries in NSW where we
know POMS can occur: risk prediction

73. Secure yellow cap tube
to floor of basket
with cable tie
Pool noodle float secured
inside basket with cable ties
Basket attached to long line rope
in such a way that it is able to float
freely at all times

74. The University of Sydney Oyster Team
Richard Whittington Ms Olivia Evans Dr Navneet Dhand
Dr Ika Paul-Pont
Ann-Michele Whittington
Dr Paul Hick
Anna Waldron Vickie Patten Alison Tweedie
Dr Ana Rubio

75. Acknowledgements
Funding agencies & collaborators
• FRDC, University of Sydney
• NSW I&I
• Sydney CMA - BBWQIP
• Hornsby Shire Council
• Siminis Oyster Systems
• Tasmanian Oyster Research Committee
• Oysters Australia
• Shellfish Culture Tasmania
Oyster growers
• Broken Bay Oysters - Bruce Alford, John Stubbs,
Rob Moxham, Steve Jones
• Endeavour Oysters – Bob, Len and Ted Drake,
Robert Hill and Keith Duggan
• Leon and Angela Riepsamen, Grenwell Point

76. Thank you for your attention