2019-01-14 General Committee Agenda - Attachment 3 to Item 2 - Monitoring of Noosa River Oyster Reefs Nov 2018

Table 5 Summary of average oyster density (with standard deviation) across all oyster
restoration sites. Note that all sites recorded significant spat settlement. Necklaces were
unrecoverable from three sites in November 2018 sue to anchor damage.
                  May 2018                                                                                        Nov 2018
                  Bags                                          Necklace                                          Bags                                          Necklace
                             2                                             2                                                 2                                               2
 Site             Avg (spat/m )               StDev             Avg (spat/m )                   StDev             Avg (spat/m )           StDev                 Avg (spat/m )    StDev
 2                114.7                       153.4             159.9                           413.5             135.7                   153.3                 212.5            316.4
 3                131.5                       132.8             217.9                           219.4             37.9                    82.4                  320.2            364.6
 4                49.6                        75.1              229.0                           274.9             72.4                    92.7                  317.6            305.0
 5                544.8                       307.4             1399.2                          961.6             473.1                   315.7                 550.5            601.5
 6                165.8                       181.3             475.0                           562.5             282.8                   323.9                 No shells recoverable
 7                191.1                       279.7             664.4                           363.3             94.5                    195.3                 No shells recoverable
 8                810.0                       944.4             1229.5                          527.7             1101.2                  984.6                 0.0              0.0
 9                300.5                       374.0             611.7                           861.9             57.8                    172.3                 672.9            278.2
 10               145.7                       156.9             842.1                           722.7             82.1                    131.5                 No shells recoverable
 11               279.8                       321.7             409.9                           377.3             178.6                   277.4                 666.1            764.4
 12               340.5                       308.6             825.5                           548.3             86.5                    126.6                 758.9            511.0
 13               589.8                       527.2             551.3                           316.8             475.4                   518.8                 1056.5           425.7
 14               142.0                       178.3             428.7                           675.4             117.2                   164.2                 793.7            468.3
 16               15.5                        60.0              0                               0                 37.8                    79.2                  45.5             150.8


                                0.35
        Proportion of oysters




                                 0.3
                                0.25
                                 0.2
                                0.15
                                 0.1
                                0.05
                                  0
                                       0-2
                                             2-4
                                                   4-6




                                                                                                                      0-2
                                                                                                                            2-4
                                                                                                                                  4-6
                                                                10-15
                                                                        15-20
                                                                                20-25
                                                                                        25-30
                                                                                                30-40
                                                                                                        40-50




                                                                                                                                               10-15
                                                                                                                                                       15-20
                                                                                                                                                               20-25
                                                                                                                                                                       25-30
                                                                                                                                                                               30-40
                                                                                                                                                                                       40-50
                                                         6-10




                                                                                                                                        6-10
                                                                                                                >50




                                                                                                                                                                                               >50
                                                                May 2018                                                                 November 2018
                                                                                                         Size Range
Figure 20 Size frequency distribution of oyster shells across all samples taken in May and
November 2018.

Cover of oysters and other sessile invertebrates
At this stage, we were not able to identify any significant settlement of invertebrates on the
outside of the coir bags. This is unsurprising as significant growth of invertebrates on the
outside of the coir mesh bags was not expected within the first year, and therefore not a
compulsory success criteria for the first year in the monitoring program. We anticipate,
however, that given the positive indications of spat recruitment and oyster growth, that it is
likely that this target will be achieved fully in the coming years. We were, however, able to
use the quadrat samples (see figure 21) to show that there has been no significant
degradation of the coir mesh, that it is still strong, and that the gauge of the rope has not
been narrowed by any natural decomposition as yet. Similarly, we not that there is minimal
macroalgal coverage on the bags (<1% in all cases), meaning that there is no significant
fouling occurring that would limit the settlement of oysters either on, or into, the oyster
restoration units into the future.

Establishment of stable biogenic matrix
The development of the reefs is in the early stages, therefore 100% of randomly selected
oyster shells were still easily moved during both monitoring events. This is unsurprising as
the development of stable biogenic matric was not expected within the first year. We
anticipate, however, that given the positive indications of spat recruitment and oyster growth,
that this performance criteria will likely will be achieved in the coming years.


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