SOAP – WAGONGA ESTUARY
Latest results May to July 2014
Wild Sydney Rock Oysters
Mortality:
The lowest wild SRO mortalities were recorded at Golden Mile, Lower Honeymoon & Punkally
Creek. The highest wild SRO mortalities were recorded at Lavender Point (2%). Note that chart
colours are the same as coloured tags for each monitoring site.
Figure 1. Mortality rate at the first grading based on dead wild SRO oyster counted and total oysters graded for each
of the four Wagonga monitoring locations
Growth:
All wild SRO started with an average shell length of 53mm. There was consistent growth across all
four monitoring sites with an average growth of 2-3mm.
Figure 2. Weighted average shell length of SRO at the first Wagonga grading.
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SOAP – WAGONGA ESTUARY
Latest results May to July 2014
Hatchery Sydney Rock Oysters
Mortality:
There was very little difference in mortality rates between the two SRO hatchery sites – Punkally
Creek and Lower Honeymoon.
Figure 3. Mortality rate at the first grading based on dead hatchery SRO oyster counted and total oysters graded for
each of the two Wagonga monitoring locations.
Growth:
Hatchery SRO were not graded using the SED grader as shell was too thin. We will grade in 2
months and report growth data then.
Oyster mortality comparison
Figure 4 shows the comparison mortality % across both oyster types and monitoring sites. There
was more mortalities in wild SRO than in hatchery SRO.
Figure 4. Mortality % comparison between all oyster types and monitoring sites
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SOAP – WAGONGA ESTUARY
Latest results May to July 2014
Other observations
Wagonga is the only estuary where a range of different cultivation methods are being used.
Punkally Creek site uses 16 SEPA baskets, Lower Honeymoon is using 4 trays, Golden Mile is using 8
floating bags and Lavender Point has used 8 SEPA baskets. Figure 5 shows these different
cultivation types and oyster mortalities. Figure 6 shows these different cultivation types and
average length after 2 months of growth.
Figure 5. Mortality % comparison between all oyster types, sites and cultivation type
Figure 6. Average length comparison between all oyster types, sites and cultivation type
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SOAP – WAGONGA ESTUARY
Latest results May to July 2014
Temperature loggers were deployed at four locations in the Wagonga Estuary – Punkally Creek,
Lower Lavender Point, Golden Mile and Lower Honeymoon. The hourly temperature results
recorded by the loggers can be seen in Figure 7 and show consistent close readings across all sites.
Lower Lavender had consistently the warmest water of all sites over the May, June and early July
period.
Figure 7. Hourly temperature readings at five locations in the Wagonga Estuary between May 10 and July 7 2014.
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