2020-07-07 P&E Agenda - Item 3 - Attachment 1 - TNC Project Management Plan

6.6 Shellfish ecosystem substrate composition and configuration considerations
The environmental and ecological considerations relevant for the selection of shellfish restoration sites is guided by
the approaches outlined in the recently released shellfish restoration guidelines6.

The basic design principles of shellfish restoration include:

1.         Identification of suitable locations within the system that maximize connectivity between shellfish
           ecosystems and other associated ecosystems such as rocky reefs, seagrasses and muddy bottoms, to
           minimize human, biological and physical threats;

2.         The laying of a locally sourced rock/rubble substrate onto the seafloor, for oysters and other associated
           species to attach to. This habitat substrate will be a composite of locally sourced igneous rock mixed with
           recycled, dried oyster shell, offering an optimal low-relief habitat on which oysters, and associate species
           such as pearl oysters, hairy mussels, tunicates, macroalgae, can readily settle and grow. The composite
           substrate provides elevation, to raise the oysters above the sediment, and hard calcareous surfaces,
           attractive to rock oysters in particular. This composite substrate is designed to mimic the natural shell ‘hash’
           that would otherwise be formed by generations of oysters recruiting onto themselves, but which has since
           been lost from the estuary;

3.         Consideration of physical features, such as aspect, height, dimensions and rugosity, in a way that can help
           mitigate physical and biological threats such as smothering, heat, erosion, predation and human disturbance;
           and,

4.         Seeding of the substrate with live oysters, while the target density of adult oysters is achieved, and/or timing
           of the laying of the substrate to coincide with peak natural oyster recruitment periods.

The final composition, configuration and deployment methods for the habitat substrate are determined by a team of
ecological and engineering advisors using physical, ecological, social and engineering parameters. Designers
particularly consider the need to balance the stability of the structure, during significant weather events, and in
consideration of edge effects and ecological resilience and the need to recover shellfish ecosystems of adequate size,
to be self-sustaining and effective, within the available project budget.

For the pilot shellfish ecosystems, two sites will be selected to test the overall replicable patch size that can be
reproduced at other locations identified by the habitat suitability analysis. The composite substrate bases at each site
are likely to be long and narrow (e.g. 50 m x 5 m) and run parallel to the shoreline occupying the lower intertidal
region or perpendicular to the shore, from the intertidal into the sub-tidal zone. The final configuration and locations
of restoration sites in the Noosa River estuary will be assessed and approved by the TAG.

6.7 Project workflow

(A4.1) Restoration at two sites (approx. 40m-50m shore length per site) which test substrate design, deployment and oyster
growth and survival.

Timeline: 24 months

     •     Review and synthesis of existing research (described in 2.2)



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         BRING BACK THE FISH: PROJECT MANAGEMENT PLAN