Restoration Plan

   

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Figure 2. Natural oyster reef structure at Toorbul Point, Queensland in the early 1900's. Reefs
constitute a structurally complex, biogenic habitat that provides feeding opportunities, shelter sites

and spawning areas for fish in estuaries. Oyster reefs can also slow erosion processes and can
improve water quality at a local scale.

 

 

 

 

        

 

Distribution of oyster reefs and restoration sites in the Noosa River Estuar
Historically, the likely spatial extent of oyster reefs in the Noosa River is estimated to be in the range
of 41,530 to 207,650 m? (ESP 2016). A minimum of 8,241 m? of oyster beds was removed per year
during the peak oyster harvest. Approximately 16,850m? of old oyster beds are currently buried by
sediment in the historical oyster lease areas. Of the original extent of naturally occurring oyster reefs
in Noosa River, approximately 20,647 m2 of degraded living oyster beds (i.e. small and isolated
patches, often heavily silt covered and containing many dead shells) remain scattered throughout the
system. These oyster beds have a low vertical profile and a low surface area : volume ratio, are easily
covered by silt (especially from wind suspension or seasonal rain events), and therefore do not
provide the same opportunities for oyster recruitment as established oyster reefs would. Additionally,
the current extent of degraded oyster beds in the Noosa River (20,647 m2) is only a small fraction of
the total area of oyster reef habitats (41,530 to 207,650 m2) that are likely to have been present
before commercial harvesting commenced. Oyster spat are, however, still present, and abundant, in
the Noosa River, and recruit to suitable hard substrate when it is present (TNC & ESP 2015).

The additional benefits provided by complex, biogenic and self-recruiting oyster reef habitats far
exceed the benefits provided by scattered oysters occurring on urban structures and cannot be
considered as oyster reefs. Having oysters in a system (e.g. oysters growing on jetties, pylons, or
artificial rock walls) does not substitute for the functional, ecological or habitat roles that natural
restored oyster reefs can provide for estuarine ecosystems. Urban structures also do not provide the
same complexity as natural systems can within the seascape (Peterson et al 2003).

The restoration sites that we have chosen as locations for oyster reef restoration in the Noosa River:

1) are in reaches of the lower estuary and in Weyba Creek from which oysters were harvested
historically (Figure 1);

2) are within the depth range known to be suitable for oyster reefs to grow;

3) are in locations where viable oyster larvae were recorded during recent recruitment studies
(TNC & ESP 2015); and

4) have an extent where the final restored area will not exceed the historical areal extent of
oyster reefs before commercial harvesting took place.

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