Enclosure 6 - ESP Letter

                                                             Ecological Service Professionals
                                                                                 Sustainable Science Solutions


Noosa River – North Shore
The area referred to as North Shore in this report includes site 6 to 10 (Figure 8). No oyster
beds or reefs were observed adjacent to or beneath the sediment surface at sites 8, 9 or 10
(Figure 8). There was at least 2 m of sandy sediment below these sites, although this is to be
expected as sediments are highly mobile in this area (where the hydrology has been
modified) and oyster beds may have been dredged in the past. There were several oysters
growing in a narrow band on a metal sign post (next to site 10; Figure 15) and some oysters
on mangrove roots at site 9. These sites are within the optimal growing area
(accommodation space) of oysters and occur within a historical oyster lease area, so there is
a high probability that oyster beds occurred at this sites but that the substrate was removed.
Sites 6 & 7 were adjacent to seagrass beds and we found hard substrate approximately
1.5 m below the sediment surface. There were no oyster beds located in close proximity to
these sites. The closest oyster aggregation was on an artificial rock wall adjacent to site 4.




   Figure 15   Oysters growing on metal pole near site 10. The shore height oysters were growing
               was limited to low intertidal and shallow subtidal (down shore of the adjacent
               mangrove pneumatophores).

Weyba Creek
This area includes sites 11 to 15 in the main channel of Weyba Creek (Figure 16 & Figure
17). Two areas of shallow shell grit were recorded in the main channel of Weyba Creek
where tidal currents are strongest (Figure 17). While numerous dead oyster shells were
found on the sediment surface (Figure 17a-c), this habitat is in the process of being covered
by shifting sediment, with many of the remnant oyster shells also buried under the surface.
Small dead oyster shells were found approximately 30 cm below the sand surface at site 13
(Figure 18). The lack of vertical height above the sediment, suitable surface orientations
(lack of overhanging surfaces) and high mobility or accumulation of sand is likely to
contribute to the low numbers of live oysters currently growing in these areas (Figure 19).
Creating restoration structures with suitable variety of natural settlement surfaces
(particularly overhang surfaces), at a sufficient height on the shore (above LAT as this is
where most oysters grow), with sufficient vertical relief (i.e. >0.5m) and stabilisation of
sediment is essential to create conditions ideal for the natural recovery of oysters in this
habitat. It appears from this assessment that the only way to do this is to reintroduce



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