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

                                                              Ecological Service Professionals
                                                                                  Sustainable Science Solutions




   Figure 21   Narrow aggregation of oysters growing in intertidal zone on coffee rock along Weyba
               Creek adjacent to leaf oyster bank.

Oysters were also recorded growing on several jetties and bridge pylons in a narrow
intertidal band; however, these artificial vertical surfaces do not replicate the same ecological
function or natural habitat complexity as natural oyster reefs and beds. Opportunities for
vertical growth of these oyster aggregations to form complex three-dimensional biogenic
structures are limited and oysters generally only form a thin veneer over the surface of
artificial structures.



Lake Weyba
The section includes sites 16 and 17 as shown in Figure 24 (note that restoration is not
planned at site 17 only water quality was taken at this site). Several natural oyster
aggregations were recorded on rocky outcrops in Lake Weyba (Figure 24), with the greatest
density of oysters aggregating in the narrow intertidal zone on the rocks (Figure 22 & Figure
24a,b). The aggregations formed on these rocks were typically only a single layer of oysters.
Salinity in Lake Weyba was measured as close to oceanic water (35.5 PSU) in October on
an outgoing tide, which is ideal for oyster growth; however, very fine sediment and dense
macroalgal growth on rocks appears to reducing the recruitment space available for oysters
(Figure 24d & Figure 23). Seagrass was recorded around the rocky areas in Lake Weyba
and was patchy throughout the Lake, although an extensive survey to assess the location
was not completed.
Sparse oyster aggregations were found on low relief rubble fields, although sedimentation
was an issue in these areas (Figure 24c & Figure 25).




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