Summary of POMS Emergency Response – Hawkesbury River
21st January to 6th February 2013
Day 1. Monday January21 – first suspicion
University of Sydney researcher Richard Whittington, Dr Ana Rubio from Hornsby Shire Council and oyster grower Bruce Alford were on the Hawkesbury river to collect routine samples from the Mullet Creek and Porto Bay experimental sites to measure oyster growth and environmental factors for FRDC project 2012-032. Fortnightly surveillance for POMS is also conducted. Nothing unusual was observed.
In mid morning oyster grower Rob Moxham saw dead spat in 3mm socks in 12mm pillow baskets that had been collected on 21 January from Mullet Creek and taken to his shed for grading. He contacted John Stubbs, president of Broken Bay Oysters Association, who rang Bruce Alford in the boat. Back at shore, Richard Whittington inspected four baskets of oysters with Rob Moxham and confirmed that at least 50% were dead. He collected a range of representative samples to test for OsHV-1, phoned Peter Kirkland in the virology lab at EMAI and hand delivered the samples to Peter in the evening. Meanwhile John Stubbs personally notified all oyster growers in the river that there was a possible disease outbreak and requested that they avoid moving oysters from Mullet Creek until the situation was clear. John also officially notified the biosecurity section of NSW DPI.
Day 2. Tuesday January 22 – POMS confirmed
The EMAI lab performed a routine qPCR assay for OsHV-1 and confirmed the diagnosis of POMS. Broken Bay Oyster Association was notified in the late afternoon and Peter Kirkland rang Richard Whittington. John Stubbs on behalf of Broken Bay Oysters requested technical advice for growers. Richard Whittington telephoned the NSW Chief Veterinary Officer Ian Roth in the evening to advise that he would provide emergency advice to growers and initiate outbreak investigation. Ian welcomed this input and advised that Sally Spence had been appointed incident controller based at DPI Orange. John Stubbs called a meeting of Broken Bay Oyster Association at 7am the next morning. Richard Whittington prepared a set of notes on a specific emergency response for the Hawkesbury River and sent these by email to John Stubbs and the Chief Veterinary Officer around 10pm.
Day 3. Wednesday January 23 – voluntary quarantine and response
John Stubbs led a meeting of Broken Bay Oysters Association members at Rob Moxham’s shed. The meeting was fully attended and commenced sharply at 7am. Growers were informed of key points from Richard Whittington’s advice: the virus could spread with tidal flows and currents; the spread of mortality is not continuous over time within a bay; the distribution of the disease can be patchy within a bay; the virus can infect oysters without the oysters showing signs of mortality; heavy mortalities can be expected in spat up to 60mm; adult oysters 10-12 months are more resistant but substantial mortality should be expected; by raising the growing height 300mm mortality can be reduced up to 50%. The aim of an emergency response is to protect the industry by stopping spread from the Hawkesbury through quarantine controls, delay spread out of Mullet Creek to the rest of the river by stopping local oyster movements, salvage value by harvesting ahead of predicted mortalities, and protect remaining stock from mortalities using husbandry. This would be helped by a survey for infection.
John Stubbs obtained unanimous agreement from growers for the following actions in the river (in addition to voluntary quarantine): all stock in Mullet to be kept in Mullet; no movement of any oysters from any other region (except for sale) to any other part of the river until surveillance testing of the Hawkesbury has been done; if stock from a lease is worked it must go back to the same lease; limit boat movements from the bottom of the river to the top; disinfect bilge water with chlorine if you have water in the punt after picking up stock to work; do not enter Patonga Creek or Brisbane Water with punts; take an inventory of stock (size, age, cultivation method, density); do surveillance testing again a month later; all media inquiries to be directed to John Stubbs or Tony Troup; keep a diary of every day work events for the next few months (environmental conditions, stock movements).
Richard Whittington met by telephone in the afternoon with Rory Arthur, NSW DPI surveillance manager, and a plan was agreed to conduct surveillance in the river to determine the extent of the infection, with the survey design to be done by the university as a matter of urgency. Funding for the survey was not clear. Hornsby Shire Council offered a range of resources to assist with the response.
DPI advised that the NSW Food Authority had approved human consumption of oysters, which facilitated harvest and sale.
Bruce Alford and Rob Moxham conducted an inspection of Mullet Creek in the afternoon and most oysters there were now dead.
Richard Whittington discussed the need for hydrological modelling to inform understanding of disease spread and enable targeted water sampling with Peter Coad at Hornsby Shire Council. Peter immediately arranged with Manly Hydrolics Laboratory to undertake the necessary modelling.
DPI held an Incident Action meeting to consider containment controls and other response requirements and sent a Draft Media Release to BBOA for comment. There was agreement that the release would not be used unless the media reported on the story.
DPI condicted a traceback on oyster movements from the Hawkesbury River and requested data from growers on stock levels/location/culture equipment.
Day 4 – Thursday 24 January
Radio station 2UE broke the news in the morning, with John Stubbs in the spotlight. NSW DPI responded by issuing a press release advising that it was the third outbreak in NSW, that there was no public health risk and that the DPI is working closely with local oyster growers to manage a closure that restricts the movements of any oysters and equipment to other estuaries. DPI manager Ian Lyall advised Richard Whittington of the media activity, and Richard later conducted interviews with the Sydney Morning Herald, which had contacted the University media office as soon as the 2UE story went to air.
Richard Whittington and Olivia Evans designed an interim sampling program to detect spread of the virus in water. Sample collection was undertaken in the afternoon by Bruce Alford and Hornsby Shire Council staff Peter Coad and Ana Rubio.
University of Sydney epidemiologist Navneet Dhand and Richard Whittington worked with preliminary data collected by Bruce Alford and Ana Rubio to devise a survey design for oyster leases in the river system. Meanwhile Bruce Alford coordinated an audit of oyster stocks in the river so that specific parameters for the survey could be decided.
In the evening Bruce Alford saw a few dead oysters in leases at Mooney Mooney. Richard advised John Stubbs not to collect samples for testing but rather to wait until the next morning and re-inspect the leases because by then the diagnosis would be clear; this would be quicker than laboratory tests.
NSW DPI issued a Quarantine Order to control movements of oysters and oyster farming equipment. DPI conducted media interviews and assisted NSW Farmers Association and Sydney Fish Market to manage media through social media links and media releases. The result of an uncoordinated release of media information to 2UE was several hours of misinformation and confusion about the food safety risk of oysters in the marketplace. DPI established an Industry Consultative Group, provided email updates and updated the DPI POMS website.
DPI sent a letter to all oyster permit holders in NSW updating them on POMS outbreak, the need for vigilance for mortalities, to consider risk management and ensure decontamination procedures were followed if moving between estuaries.
Day 5 – Friday 25 January
The Sydney Morning Herald covered the story of POMS in the Hawkesbury River as its front page lead.
In the morning John Stubbs reported that Mooney Mooney, Goat Island and Spectacle Island leases were now affected.
Oyster growers continued to harvest and sell oysters ahead of possible disease spread.
Bruce Alford completed the stock audit and this was sent to the University and used to finalise the design for the survey. In the afternoon Richard Whittington sent the completed survey design to Broken Bay Oysters and DPI, with a plan for implementation on Tuesday 29 January, subject to weather and current information about disease spread.
Results from the tidal modeling were provided to Hornsby Shire Council. The results suggested tidal movement of 6 to 16 km upstream from Mullet Creek with each tide cycle.
In the evening Bruce Alford reported that a grower had been to the top of the Mooney Mooney leases and they were not affected.
A voluntary closure of Brisbane Water to oyster and oyster farming equipment movement commenced.
Day 6 – Saturday 26 January
Broken Bay Oysters Association planned a meeting to discuss research needs to be held at 2pm Tuesday 29 January and requested comments and ideas. Richard Whittington prepared a set of notes about research themes and circulated it to all participants.
Day 7 – Sunday 27 January
Richard Whittington compiled all available information about reported mortalities and oyster movements in the river and plotted these on a map.
Day 8 – Monday 28 January
Richard Whittington sent interim trace forward analysis to Broken Bay Oysters with a request for additional information to complete the analysis. The audit was completed by Steve Jones and Bruce Alford and sent to NSW DPI and the University.
NSW DPI Biosecurity met in the afternoon to define a survey to identify high risk oyster movements (trace forward from Mullet Creek within incubation period, assumed to be 8 days) and strategic locations such as Brisbane Water.
Crispian Ashby from FRDC met with BBO growers at 4 pm at Mooney Mooney.
Day 9 – Tuesday 29 January
Olivia Evans, Ana Rubio, Richard Whittington and boat driver Jeff Collins set off from Mooney Mooney at 8am to collect water samples from the length of the lower Hawkesbury River to assess the spread of virus in water. They returned at 12.30 pm.
NSW DPI on behalf of the Department of Premier and Cabinet, invited growers to a support meeting at Mooney Mooney at 10.30am, to provide information on assistance options to help oyster farmers impacted by stock loss and support discussion on future directions for their businesses. The NSW Minister for Primary Industries Katrina Hodgskinson and the local MP Chris Holstein visited the site and met with growers at 3.30pm. DPI, Hornsby Shire Council and University staff were present.
Projected financial losses necessitated some growers terminating employment of their staff today – this was a very sad day.
Oyster growers convened a meeting with researchers and Crispian Ashby from FRDC at 2pm to discuss possible avenues for future oyster production including diversification of species, use of genetically resistant stock and husbandry techniques.
Oyster grower Reg Richards advised that the crew of a boat just returned from upper Mooney Mooney Creek had observed widespread mortality.
At 4.30 pm Richard Whittington coordinated scientists, growers and volunteers to implement a harmonized survey which would link the University of Sydney whole of river survey and the DPI trace forward survey. Richard issued plans for sample collection and equipment to four boat crews, who each went to a different location to collect samples:
The crew on each boat, representing BBO growers, Hornsby Shire Council, DPI and University of Sydney were:
Kimerikong then Marra Marra – John Stubbs, Wayne O’Connor, Olivia Evans
Marra Marra– Bruce Alford, Richard Whittington, Paul Hick
Porto Bay – Shane Moxham, James Moxham, Peter Coad,
Coba Bay – Rob Moxham, Steve McOrrie, Ian Lyall, Ana Rubio
During sample collection dead oysters were observed in a lease at Coba Bay. The trays had been moved from Mullet Creek on 19th January. Rob Moxham felt the odds were high that these oysters from his lease would be positive.
The boats returned with samples by 9pm. Samples were taken directly to the EMAI and University of Sydney laboratories.
Day 10 – Wednesday 30 January
Samples from the one lease in which dead oysters were observed yesterday were processed at EMAI as a priority and the results were positive for OsHV-1 indicating that the virus was now present in Coba Bay. BBO growers were notified of the results by DPI.
Olivia Evans processed water samples from the river at the University of Sydney laboratory. Staff at both laboratories prepared materials to process the oysters from the survey.
Meanwhile Bruce Alford collected samples from Patonga on the early morning low tide, accessed by road. Rob Moxham, Ana Rubio and Bruce Alford worked on the afternoon low tide to collect the last samples for the survey from Marra Marra and Porto Bay.
Kerry Wells from Shellfish Culture, the hatchery in Tasmania which is the primary supplier of spat for the river, visited BBOA growers to assess the situation and offer support for research trials leading to restocking of the river.
DPI met with Port Stephens Fisheries Institute hatchery staff to review and update existing biosecurity protocols.
Day 11 – Thursday 31 January
With a team of 5 people over 10 hours, the University of Sydney laboratory opened over 1000 oysters and took tissue samples from gill and mantle for qPCR tests. Anna Waldron, Ann-Michele Whittington, Vickie Patton and James Dalton opened and dissected all the oysters while Karren Plain performed the FastPrep procedure to homogenize oyster tissues, and Craig Kristo looked after waste disposal (there was a lot). Alison Tweedie then purified DNA on a magnetic particle processor.
Rob Moxham and his right hand man Mitch delivered the last oyster samples from Patonga, Marra Marra and Porto Bay to the University laboratory. Rob and Mitch looked over the lab and saw the equipment in action that supports the whole diagnostic process. Paul Hick arrived at the University in the late afternoon to exchange some samples for the respective surveys. He also had faced a huge task during the day at the EMAI lab to complete processing of a huge number of samples.
DPI undertook sampling of wild Pacific oysters in Brisbane Water. DPI also investigated mortality of Pacific oysters in Port Stephens, with samples shipped overnight to EMAI.
Day 12 – Friday 1st February
qPCR assays for OsHV-1 in oyster tissues were undertaken by Alison Tweedie at the University and Paul Hick at EMAI. Meanwhile Olivia Evans completed the assays on water samples at the University. Overnight Paul Hick, Peter Kirkland and Richard Whittington discussed the results from both laboratories by telephone. Richard sent the results from the University of Sydney survey to Ika Paul-Pont who was working in France for verification and Ika responded with detailed comparisons with data that had been collected from the Georges River over two years. Meanwhile overnight Navneet Dhand calculated accurate prevalence estimates for each lease and bay.
DPI completed sampling of wild Pacific oysters in Brisbane Water. Results from the Port Stephens mortality event were negative for POMS.
Day 13 – Saturday 2nd February
Richard Whittington notified the New South Wales Chief Veterinary Officer Ian Roth of the results of the Hawkesbury River survey. Richard then rang John Stubbs to advise that OsHV-1 had been detected in river water at low levels from the entire estuary, i.e. from the oceanic mouth near Juno Point to several kilometers upstream of all oyster leases in the main river channel at Big Jims Point. The virus was also present on all oyster leases included in the survey, mostly at low levels. The exception was a lease in Coba near where oysters had been moved from Mullet creek – it had high levels of OsHV-1. Based on interpretation of the data from Ika Paul-Pont, in particular disease behaviour in the Georges River, Richard advised John Stubbs that mortality could be expected in all leases, that it might occur anytime – the range based on Georges River experience could be 2 weeks to 2 months after arrival of virus, and that the trigger for this was unknown. As the virus was already present in all bays there was no logical reason not to move oysters within the Hawkesbury system to attempt finishing for harvest. Richard Whittington also advised John Stubbs to avoid unnecessary handling of oysters due to anecdotal reports from France that stress might trigger mortality.
Meanwhile on the morning low tide Bruce Alford and Ana Rubio worked in the rain to collect samples from hanging baskets and sentinel leases in Porto Bay from the FRDC long-line experiment. The aim of this experiment, which was set up in 2012, was to determine whether oysters can be grown at extreme heights, as a possible strategy to avoid OsHV-1 infection.
Heavy rain fell in the catchment overnight, leading to probable extension of a closure; this prevents harvest and sale of oysters from the river for at least a week.
John Stubbs issued an update to Broken Bay oyster farmers of the survey results from all leases in visually uninfected areas. Their worst fears have now been confirmed:
- virus in all water samples from West Head (oceanic) to Big Jims (furthest lease upstream). Has spread throughout system
- oysters at all locations positive. No lease had negative sample.
- only lease that had high levels was Coba ( Robs trays that were moved )
- all areas showed similar positive results eg: Marra 6 to 55% of samples positive.
- Porto Bay and Patonga low levels in oysters and water
- need to discuss movement restrictions now that POMS throughout system.
- next round of mortality 2 weeks, 2 months anyones guess
- DPI view whole of Hawkesbury infected
- DPI focus now on rest of state
- decisions we make now are up to group. When river opens try to sell any stock with condition.
- avoid handling/stressing straight forward moves of trays without grading recommended if we decide any movement.
NSW DPI extended its disease control planning to the estuary at highest risk – Port Stephens. DPI issued notice of a meeting with growers on Wednesday February 6 at Karuah to discuss implications of POMS for Sydney rock oyster and Pacific oyster growers.
Day 15 – Monday 4th February
Bruce Alford, Richard Whittington, Ana Rubio and Olivia Evans systematically inspected all leases in Mullet Creek. Three well-separated trays or baskets were examined in each lease and this confirmed 99-100% mortality except in a few trays with large oysters where there were a few survivors.
Plans for short term research to indentify the infection risk period in the Hawkesbury River and options for spat rearing in the face of the infection were discussed over lunch with John Stubbs, Bruce Alford, Rob Moxham and the research team.
Additional water samples were collected from the main channel at Mooney Mooney and also from upper Mooney Mooney Creek in the afternoon on a rising tide, in an attempt to assess the current levels of water borne infection.
Day 16 – Tuesday 5th February
NSW DPI sent a letter to 60 commercial fishers in the Hawkesbury River updating them on the POMS outbreak and advising decontamination procedures if moving between estuaries. A formal Quarantine Order for Brisbane Water was made to prevent the movement of oysters or oyster farming equipment. DPI also updated its website with additional times lines, maps and decontamination information, and a POMS Industry update was provided to the NSW Farmers Association.
Richard Whittington and Olivia Evans complied records of oyster samples collected during 2012 from the Hawkesbury River as part of FRDC projects 2011-053 and 2012-032. These samples may be able to be used to determine the time of arrival of the virus in Mullet Creek.
Day 17 – Wednesday 6th February
DPI sent an e-mail to 35,000 recreational fishers updating them on the POMS outbreak and advising decontamination procedures if moving from the Hawkesbury River, Georges River and Port Jackson to another estuary. The DPI Executive Director of Fisheries met with Broken Bay Oysters Association.
DPI convened a meeting of growers at Karuah at 6pm. The agenda included a summary of the Hawkesbury River POMS outbreak, management of POMS (Brisbane Waters closure, decontamination procedures for the industry, PSFI hatchery protocols), what will happen if POMS is detected in another estuary, obligation to notify NSW DPI of mortalities, testing and surveillance, quarantine orders and a questions and answer session.
At the University of Sydney Olivia Evans, Vickie Patton and Natalie Schiller commenced processing of archival samples from the Hawkesbury river, and water samples collected earlier.