Modern middens: Shell recycling for restoring an endangered marine ecosystem in Victoria, Australia

Abstract

Shellfish reefs are one of the most depleted marine ecosystems in the world, and there is considerable interest and efforts to restore the ecosystems. When degraded reefs require the addition of new substrate to support oyster re-establishment, recycled shells can be used to rebuild new reef bases. Shell recycling as a means of procuring shells was first introduced in Australia by The Nature Conservancy in 2015, through the establishment of the 'Shuck Don't Chuck' Shell Recycling Project in Victoria. The recycling project was first piloted in the regional city of Geelong with the aim of providing sufficient quantity of clean, recycled shell to support reef base construction for shellfish reef restoration in Port Phillip Bay. The project has subsequently expanded into markets and restaurants in Melbourne. Community involvement and restoration promotion are important secondary outcomes of the programme. We provide lessons from our experience to date and a step-bystep guide of how to establish a shell recycling project from initial pilot and trial stages to a full programme. These steps include the following: (i) recruitment of shell recycling partners, (ii) transport and logistics, (iii) shell storage sites, (iv) biosecurity and curing protocols, (v) hatchery use, (vi) reef deployment, and (vii) community engagement. Shell recycling is an effective way to not only source substrate for restoring shellfish reefs, but also to reduce the amount of waste going to landfill and should be considered as part of any shellfish reef restoration project which utilises shell products.

Turning a lost reef ecosystem into a national restoration program

“…To provide visual imagery for outreach, restoration scientists collaborated with an artist to develop a series of artistic impressions of a developing reef restoration (Figure 3 ) that now serves as an online educational tool (TNC's Life on an Oyster Reef [natureaustralia.org.au/what‐we‐do/our‐priorities/oceans/ocean‐stories/oyster‐reef‐habitat/]). As the scale of projects has increased, so have opportunities for community volunteering to assist with onshore preparation activities, such as shell recycling and cleaning (Branigan et al., 2020 ). For example, OzFish volunteers now conduct a range of activities from project fundraising and planning, to site mapping, project delivery and monitoring with guidance from local research institutions.…”

Contemporary Oyster Reef Restoration: Responding to a Changing World

“…The environmental footprint associated with substrates also varies, and is generally less for naturally occurring materials (Table 2). Shell generally has a low environmental footprint, particularly where it is sourced from restaurants through shell recycling programs (Branigan et al, 2020) and has been appropriately treated through UV exposure (i.e., curing) or boiling, to kill any hitchhiking species or parasites (Jeffs et al, 2019;Branigan et al, 2020). Transportation of shell across large distances, extraction by dredge and/or inadequate biosecurity control may, however, inflate this.…”

An environmental DNA approach to informing restoration of the functionally extinct oyster, Ostrea angasi

“…Active shellfish reef restoration efforts are currently being undertaken in Port Phillip Bay (McAfee et al, 2022). A 12‐ha limestone reef has been constructed to restore shellfish reef habitats and was seeded with oyster spat from the Victorian Shellfish Hatchery (The Nature Conservancy, 2018; Brannigan, Fitzsimons & Gillies, 2020). Widespread restoration of functional shellfish reef ecosystems in Port Phillip Bay will require expansion and replication of these newly constructed reefs.…”