2016-12-12 General Committee - Attachments 1, 2, 3 to Item 10 - Oyster Restoration Project

                                                                            Attachment 2 - ESP Report




                                                                               Ecological Service Professionals
                                                                                                        Sustainable Science Solutions




Cherie O’Sullivan                                                                            Our Reference: L1533.3
Environment Officer
Noosa Council
PO Box 141,
Tewantin, QLD, 4565

7 November 2016

RE: Assessment of Oyster Habitat in Noosa River Estuary

Dear Cherie,
Thank you for the opportunity to assist Noosa Parks Association and Council to provide a
preliminary assessment of the location of current and historical oyster reefs in the Noosa
River Estuary. Please find below our advice based on a desktop review of information
available and a 2-day field assessment on the 25th and 26th of October 2016.



Executive Summary
The purpose of this report is to demonstrate to fisheries that the proposal to install oyster reef
recruitment units in a Resource Allocation Area of 90 m2 at each of 16 sites (i.e. covering a
total maximum surface area of 1440 m2) will represent restoration of habitat that existed
historically in the Noosa River Estuary but was removed by early settlers and will not result in
the substitution of sand habitats with oyster reef habitat types. This has been demonstrated
through: a historical assessment of the presence of oysters; calculation of live oyster harvest
area (based on reported oyster densities); field assessments of current environmental
conditions (water temperature, salinity, pH, dissolved oxygen and turbidity); and, a field
assessment of the presence of areas where oysters naturally grow.
Oyster reefs are in decline globally due to a range of factors including historical
overharvesting and degradation of estuarine habitat. Oyster reefs elsewhere in world, in
estuaries that also contain everglades, typically cover 1 - 5% of the accommodation space
(area suitable for oyster growth) in an estuary.
Historical oyster reefs were present in the Noosa Estuary as evidenced by past fisheries
records and other historical accounts including indigenous knowledge.
Conservative estimates of the number of live oysters harvested in the early 1900s and
current densities of oyster reefs measured in the USA were used to extrapolate the
maximum area of live oyster harvested in Noosa in the early 1900s, which conservatively
was 8241 m2 to meet the peak harvest demand. This does not include removal of dead shell
for construction purposes.
Current water quality parameters (primarily temperature and salinity) are most suitable for
oyster growth at sites downstream of approximately site 2 in the main Noosa River Channel,
in Lake Weyba and Weyba Creek. Although conditions could be tolerated by rock oysters at
all sites.



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