Key events summary

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Primary Industries Minister Katrina Hodgkinson met with affected oyster farmers at Mooney Mooney on January 29 (Peter Coad)

Timeline

Day 1 – Monday

January 21

Dead oysters noticed in 3mm baskets at a lease in Mullet Creek; Broken Bay Oyster Association (BBOA) notified a disease event to the Department of Primary Industries (DPI); samples were submitted to DPI
Day 2 – Tuesday January 22 OsHV-1 infection was confirmed by the DPI EMAI laboratory; an emergency response commenced; a voluntary quarantine of the HawkesburyRiver was implemented by BBOA
Day 3 – Wednesday January 23 Formal quarantine announced by DPI; millions of oysters in Mullet creek were confirmed dead; spread of disease along length of this bay was confirmed; BBOA adopted strict controls over movement of oysters around the river pending a survey. The NSW Food Authority confirmed that oysters were safe for human consumption.
Day 4 – Thursday January 24 A few dead oysters were noticed in an adjacent bay at Mooney Mooney; the media reported the outbreak on radio and television.
Day 5 – Friday

January 25

Mass mortality was confirmed in leases at Mooney Mooney and adjacent areas; oyster growers harvested and sold adult stock from upriver leases ahead of predicted disease spread; a trace forward investigation and a whole of river survey were planned.
Days 6 and 7

January 26 and 27

Background information was assessed; the oyster harvest continued.
Day 8 – Monday

January 28

The trace forward analysis was revised and survey designs were completed.
Day 9 – Tuesday January 29 Government agencies met with growers to discuss support measures; the Minister for Primary Industries visited the growers; sampling for the whole of river survey began using four boats/teams.
Day 10 – Wednesday

January 30

Sample collection for the survey was completed; two laboratories commenced to process oysters; the first results confirmed spread of OsHV-1 from Mullet Creek to CobaBay with movement of oysters on 19th January (trace forward positive).
Day 11 – Thursday January 31 Two laboratories processed over 1500 oysters.
Day 12 – Friday February 1 Both laboratories undertook qPCR tests for the virus and compiled the results during the night.
Day 13 – Saturday February 2 The results of the survey were sent to the NSW Chief Veterinary Officer and BBOA growers. The virus was detected in all leases in all bays and in water samples throughout the river. Ongoing mortalities were predicted across the river. Oyster growers met to plan emergency harvest.
Day 15 – Monday February 4 An independent survey of Mullet Creek confirmed 99 – 100% of young oysters on all leases were dead; detailed planning for the recovery phase in the Hawkesbury river commenced.
Day 19 – Friday February 8

 

Dead oysters were observed on another lease in CobaBay
Day 22 – Monday February 11

 

A systematic survey of CobaBay was conducted to record mortalities on each lease
Day 26 – Friday  February 15 Widespread mortality was observed on leases at PortoBay.

 

Day 37 and 38 – Wed-Thur

February 27 -28

 

A systematic survey of all leases in CobaBay, Marra Marra Creek, Mooney Mooney Creek and PortoBay was conducted. Mass mortality was confirmed in all leases in Mooney Mooney Creek and PortoBay.

All nursery stock in the HawkesburyRiver were confirmed to have died during the outbreak, with very heavy losses of adult stock in leases in the lower river. Mortality at Coba Bay was substantial.

Day 39 – Friday March 1 Recent rain events in the catchment caused dangerously low salinity levels in the HawkesburyRiver system. This necessitated a decision about emergency relocation of all adult stock from the upper leases in CobaBay, Marra Marra and Kimmerikong, to downstream leases where salinity levels will increase sooner. This movement of oysters began during the previous week. Oysters left in the upper leases are susceptible to mortality due to prolonged freshwater immersion.

We estimate immediate losses of production this season to be >$3M, with zero prospect of restocking juvenile oysters. This means that 2014 production will also be zero.

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