We evaluate the status of shellfish reef ecosystems in Australia including their historical distribution and loss, regulation and management and identify current research priorities, policies and conservation mechanisms that can enable their future protection and repair. Eight species of shellfish were identified as developing complex, three-dimensional reef systems over large scales in intertidal and subtidal areas across tropical, subtropical and temperate Australia. A dramatic decline in the extent and condition of Australia’s shellfish reef ecosystems occurred during the mid-1800s to early 1900s in concurrence with extensive harvesting for food and lime production, habitat modification, disease outbreaks and a decline in water quality. Despite early attempts during the late 1800s to curb over exploitation and repair degraded reefs through protection, primitive aquaculture and enhancement, living examples of shellfish reefs are now rare. Only one Ostrea angasi reef is known to exist that is comparable in size to reefs historically commercially fished, compared to at least 118 previously known locations. Out of the 60 historically fished locations identified for Saccostrea glomerata, only five are known to still contain commercially harvestable sized reefs. The introduced oyster Crasostrea gigas is increasing in reef extent, whilst data on the remaining five reef-building species is limited, preventing a detailed assessment of their current status. Our knowledge of the extent, physical characteristics, biodiversity and ecosystem services of natural shellfish reefs in Australia is extremely limited.
Australia is well equipped to reverse the decline of shellfish reef ecosystems with a number of state and federal protection laws, international conventions and management mechanisms already in place, all of which can be used to help protect remaining reefs and aid in future recovery. Several restoration projects have recently begun as awareness of historical loss grows amongst the community and groups become motivated to implement repair. As momentum continues to grow, Australia could serve as a long-term model for other regions that may currently have limited understanding of their shellfish reefs ecosystems but wish to work towards their future conservation.
Data to be made publicly available with publication of manuscript by end 2018.
