Restoration Plan

 

1. History of oystering in the Noosa River

The commercial oyster industry in the Noosa River commenced in the 1870's or 1880s, and ceased,
having become economically unviable, by the 1940's (Thurston 2015). Oystering locations were
recorded by local fisheries officials throughout this period. Historical maps (from 1934; see Figure 1)
outline the extent of the oyster lease areas, indicating the most probable historical range of oyster
beds within the estuary. These oyster lease areas were dredged intensively for oysters in the early
1900’s, resulting in the removal of live oyster beds and the underlying bedrock. This resulted in the
loss of large areas of intertidal and subtidal hard substrates that are required for oyster spat to settle,
grow, and form reefs. The endpoint of this process was that oyster reefs were no longer present as a
substantial habitat in the lower and middle reaches of the estuary (Thurston 2015).

  

Figure 1. A hand-drawn chart from 1934, made by the Fisheries Inspector to highlight the areas in the
Noosa River closed to net fishing. The red numbers indicate the locations of all known Noosa oyster
sections. Source: Queensland State Archives.

 

2. Importance of oyster reefs as estuarine habitats

Oyster reefs are biogenic structures in which subsequent generations of larval oysters settle on older
generations, and continue to grow progressively outwards. Occurring predominantly in the lower
intertidal throughout south-east Queensland, oyster reefs provide structurally complex and food-rich
habitat for a diversity of fish species, including many species which are of commercial and/or
recreational value (Diggles 2013) (Figure 2).

The importance of Oyster reefs as a habitat type is recognised within the Convention on Wetlands of
International Importance (The Ramsar Convention — habitat type ‘Ga’) (Kasoar et al. 2015). Oyster
reefs provide critical habitat for estuarine fishes through two key mechanisms: 1) by affording
structural complex structure within estuaries that fish use as habitat for resting, seeking refuge from
predators, and spawning; and 2) by delivering a diversity of food resources for fishes, including
planktonic prey, smaller fishes, and the oysters themselves, which occur in higher concentration in
and around the reefs (Harding and Mann, 2001). As a consequence, just 10m? of restored oyster
reefs have been shown to yield an additional 2.6 kg of fish biomass per year over the lifetime of the
reefs relative to sandy substrates (Peterson et al. 2003).

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