Skip links and keyboard navigation

Intertidal molluscs on consolidated substrate (shellfish reefs)

Short description

Mollusc communities forming shellfish reefs, typically dominated by oysters with or without barnacles, growing on intertidal rocky shores including rock platforms and pavement.

Disclaimer: Ecosystem type descriptions are based on biophysical attributes identified in Central Queensland through expert advice and supported by scientific literature. Not all ecosystem types are mapped based on current inventory, and many of the ecosystems described here may also occur in other parts of Queensland.

Oysters on consolidated. Photo by Maria Zann

Classification categories

Select from the links below to view related ecosystem type categories

Long description

Mollusc communities on intertidal rocky shores including rock platforms and pavement. Fourteen species of bivalve mollusc are known to form shellfish reef ecosystems, with their extent in Queensland poorly known[2]. Other shellfish ecosystems grow on, or form, consolidated ecosystem types. These ecosystems are typically dominated by the oysters (Ostraeidae) Saccostrea cucullata (milky oyster) and Saccostrea glomerata (rock oyster)[2], with or without barnacles, mostly from the family Chthamalidae and Balanida but also Lepadidae[1]. A range of temperate, sub-tropical and tropical biota can also occur, including encrusting algae, erect macrophyte algae, bryozoans, chitons (Chitonidae), limpets (Patellidae, Patelloididae, Fissurellidae, Siphonariidae), periwinkles (Littorinidae), top shells (Trochidae), turban shells (Turbinidae), nerite shells (Neritidae) and other gastropods (e.g. Planaxidae, Thaiidae, Mytilidae), hydroids (Dynamena crisoides), zoanthids (Zoanthidea), sea stars (Asteroidea), anemones (Actinia tenebrosa, Cnidopus verater) and polychaeta worms (Onuphidae, Serpulidae)[1]. Other shellfish ecosystems grow on unconsolidated substrates. Isignomon ephippium (leaf oyster) can also be found on these consolidated substrates but is typically habitat forming on mud and sand[2]. See types (20, 64, 65, 118).

Special values

Oysters and mussels are ecosystem engineers that create shellfish reefs that provide, modify and maintain habitats for a range of other species. Shellfish reefs provide a range of ecosystem services, including food provision, fish and invertebrate habitat, water filtration, fish production and shoreline protection[2].

For thousands of years, Traditional Owners caught and ate large numbers of shellfish species in and around the Queensland coast. Often they would cook the meat and use the shells for a number of purposes, or dispose of shells in large dump sites called shell middens. Shell middens have provided important information and clues about Traditional Owners and the environment they lived in. The middens tell the story of the Traditional Owners’ diet, food sources and species available and the impact of environmental changes on biodiversity and marine ecosystems[4].

Can form a habitat of modified Naturalness (e.g. rock walls and jetties). Artificial shellfish reefs are an emerging technology designed to treat and improve water quality.

Diagnostic attributes

Inundation 'Intertidal – Lower low', 'Intertidal – Mid low', 'Intertidal – Upper low', 'Intertidal – Low undifferentiated', 'Intertidal – Lower medium', 'Intertidal – Upper-medium', 'Intertidal – Medium undifferentiated', 'Intertidal – High', 'Intertidal – Undifferentiated', 'Intertidal – High undifferentiated'

Structural macrobiota 'Mollusc – other', 'Mollusc – oyster', 'Mollusc – scallop', 'Mollusc – barnacles'

Consolidation 'Consolidated'


Modified ecosystems (e.g. oyster leases) are unmapped. Oysters and barnacles may also occur on modified consolidated ecosystems (type 24).


Tropical species typically occur north of approximately 25 degree south with temperate species to the south of this boundary[1][3]. This boundary coincides with a change in wave energy from high wave energy Fraser Island southward to low wave energy within the Great Barrier Reef lagoon[3]. In northern Queensland, the oyster Crassostrea amasa was the most conspicuous fauna and covered most of the rocky substrate between high water neap and mean sea level (i.e. upper intertidal). In southern Queensland, on high energy shorelines, this upper intertidal zone was dominated by the Rose Barnacle (Tesseropora rosea) and very few oysters are present. There is a very small area of overlapping temperate and tropical species around the latitude 25 degrees south. The Moreton Bay-Caloundra region also provides refuge for some tropical species[1].

Zonation patterns differ to the north and south of this biogeographical boundary. In northern Queensland, the oyster C. amasa dominates the upper intertidal with the large barnacle Tetraclita squamosa dominating the lower intertidal. In southern Queensland (and New South Wales), the serpulid tube-building polychaete Galeolaria caespitosa dominates in the lower intertidal and the barnacle T. rosea dominates the upper intertidal[1].

Artificial reef construction is underway across parts of Queensland including Moreton Bay and the Noosa River to provide artificial habitat and treatment systems to uptake nutrients and other potential contaminants.

The following relates to distribution of this ecosystem type within the Central Queensland mapping area:

  • In Central Queensland, oysters tend to be in lower energy habitats and barnacles tend to be higher on the shore as they can tolerate less frequent inundation.
  • The most common shellfish ecosystems in Queensland were originally much more extensive and dominated by Saccostrea glomerata, but they have dramatically declined[2]. Oyster harvesting of mostly S. cucullata and S. glomerata was a major industry in Wide Bay and Port Curtis from the 1860s to the 1920s, but oysters were impacted by disease and water quality. Pinctada albina sugilatta (pearl oyster) and Saccostrea echinata (black lip oyster) can be found on these consolidated substrates but are rarely ecosystem forming in Central Queensland[2].


Typically intertidal oyster ecosystems occur on low energy consolidated substrates[1] although this is not a diagnostic attribute. Changes in Energy source and magnitude can also modify which species will be present.

Additional Information

Molluscs - Queensland Museum

Shellfish Reef Restoration Network


  1. ^ a b c d e f Endean, R, Kenny, R & Stephenson, W (1956), 'The Ecology and Distribution of Intertidal Organisms on the Rocky Shores of the Queensland Mainland', Marine and Freshwater Research. [online], vol. 7, no. 1, p. 88. Available at: [Accessed 30 April 2019].
  2. ^ a b c d e f Gillies, CL, McLeod, IM, Alleway, HK, Cook, P, Crawford, C, Creighton, C, Diggles, B, Ford, J, Hamer, P, Heller-Wagner, G, Lebrault, E, Le Port, A, Russell, K, Sheaves, M & Warnock, B (14 February 2018), 'Australian shellfish ecosystems: Past distribution, current status and future direction', PLOS ONE. [online], vol. 13, no. 2, p. e0190914, ed. L D Coen. Available at: [Accessed 25 March 2019].
  3. ^ a b Poloczanska, ES, Smith, S, Fauconnet, L, Healy, J, Tibbetts, IR, Burrows, MT & Richardson, AJ (2011), 'Little change in the distribution of rocky shore faunal communities on the Australian east coast after 50years of rapid warming', Journal of experimental marine biology and ecology, vol. 400, no. 1, pp. 145-154, Elsevier.
  4. ^ Queensland Museum Network, 'Indigenous Science: Shell middens and fish traps', The Queensland Museum Network Blog. [online] Available at:

Last updated: 22 July 2019

This page should be cited as:

Department of Environment, Science and Innovation, Queensland (2019) Intertidal molluscs on consolidated substrate (shellfish reefs), WetlandInfo website, accessed 18 March 2024. Available at:

Queensland Government
WetlandInfo   —   Department of Environment, Science and Innovation