2015-11-10 - P&O Agenda - Item 7, Attach 2 - Assessment of Oyster Recruitment

   a)                                                     b)




    Figure 2.   Vertical and horizontal settlement tile array in (a) Lake Doonella, and (b) Weyba Creek

Tiles were deployed in December 2014. The intertidal tile arrays were checked and cleared
of silt in February 2015, then retrieved in May 2015. At the subtidal sites, one array was
collected and new tile arrays were redeployed in February 2015; all remaining tiles were
retrieved in May 2015 (Figure 3). Assessing recruitment over time by deploying tiles in
December 2014 and February 2015 allowed us to determine temporal differences in the
recruitment of oysters, and the period when recruitment was maximised during
summer/autumn. An additional array of 4 horizontal and 4 vertical tiles was deployed under
a jetty in Noosa Sound in February 2015, and an additional array of 4 horizontal and 4
vertical tiles was also deployed 0.5 m from the bottom at Site WC2 in Weyba Creek for 5
months. A total of 206 tiles were deployed and examined over the duration of the project.
Eight tiles were lost during the project, all from site WC3 (Table 1).

Tiles were collected in the field by hand, photographed and the size and number of oysters,
and presence of other sessile species on each settlement tile (and associated deployment
structures) was recorded. A stereoscope was used to confirm the species of oyster and
presence of any recent recruits that were not visible in the field.

The number of barnacles, mussels and pearl oysters and presence of bryozoans, ascidians
and sponges were also noted for each plate (however, these groups were only identified to a
high taxonomic level as they were not the primary focus of this project).




Restoration of Noosa Estuary: An Assessment of Oyster Recruitment                                     5