Rewilding Our Ocean

TNC’s pilot Shellfish Habitat Restoration Project in Tolo Harbour shows progress

November 23, 2022

Monitoring Growth of the Reef TNC has been monitoring the artificial reef’s growth and its impact on biodiversity on an ongoing basis. © TNC

The Nature Conservancy Hong Kong (TNC) announced that its pilot Shellfish Habitat Restoration Project in Tolo Harbour has shown progress. The first reef survey conducted two months after the deployment of an artificial reef onto the seabed proves that abundant and diverse life was found settling on the reef, and there are signs showing that it is also attracting commercial crab and fish species, including big snappers.

**Reef Building** Members of TNC Hong Kong team deploying recycled oyster shells into the Tolo Harbour in June 2022 © TNC

In partnership with local fish farmer Alex Lam, TNC deployed the artificial reef in June 2022 using recycled oyster shells, aquacultural debris and limestones near a licensed fish raft in Yung Shue Au Fish Culture Zone (FCZ). The oyster shells were collected from restaurants and local oyster farmers participating in TNC’s “Save Our Shells” initiative, which were treated in the sun for disinfection and bagged in biodegradable mesh bags. The aquacultural debris used in constructing the second layer of the artificial reef was weathered concrete poles used by traditional oyster farmers in Deep Bay. These are encrusted with oyster shells and collected by TNC volunteers on the Pak Nai mudflats over the past two years.

Supported by The Agriculture, Fisheries and Conservation Department (AFCD), the Tolo Harbour pilot aims to enhance the development of sustainable aquaculture in the FCZ, whose marine environment had suffered due to overharvesting and pollution.

Further assessments will be conducted to evaluate whether the artificial reef is successful in mitigating nutrient loading from fish farms and increasing biodiversity, especially the fish species utilizing the reef.

The pilot can be successful in informing sustainable mariculture development as well as restoration strategies in Tolo Harbour, and will be used as a benchmark to inform the scale of restoration that is needed in the future

Marine Thomas

Senior Conservation Program Manager, for TNC Hong Kong

TNC will continue to assess the site and monitor the recruitment of reef-building bivalves and other marine life, fish species that utilize the reef, and the nutrient mitigation potential of shellfish reefs in Tolo Harbour over the next 1.5 years.

Rewilding Our Ocean TNC deployed an artificial reef in June 2022 using recycled oyster shells, aquacultural debris and limestones near a licensed fish raft in Yung Shue Au Fish Culture Zones as part of its pilot Shellfish Habitat Restoration Project.