''Saccostrea glomerata'' is an

oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but no ...

species belonging to the family

Ostreidae The Ostreidae, the true oysters, include most species of molluscs commonly consumed as oysters. Pearl oysters are not true oysters, and belong to the order Pteriida. Like scallops, true oysters have a central adductor muscle, which means the s ...

.MolluscaBase eds. (2022). MolluscaBase. Saccostrea Dollfus & Dautzenberg, 1920. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=138300 on 2022-04-27 It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. In Australia, it is known as the Sydney rock oyster and is commercially farmed. In New Zealand, where the species is no longer farmed, it is known as the New Zealand rock oyster or Auckland oyster.

Taxonomy

The Sydney rock oyster and New Zealand rock oyster have previously been classified as two separate species: ''Saccostrea commercialis'' and ''S. glomerata'', respectively. (paywall) These species have also been grouped with the hooded oyster into a single species, '' S. cucullata''. The species is currently considered to be closely related to ''S. cucullata'', which is common on Indo-Pacific rocky shores. When proposing the name ''Ostrea commercialis'' in 1933, Iredale & Roughley noted that the New South Wales oyster had been variously referred to species ''O. cucullata'' Born (Ascension Island), ''O. mordax'' Gould (Fiji), ''O. glomerata'' Gould (New Zealand), ''O. circumsuta'' Gould (Fiji); and even to ''O. trigonata'' Sowerby and ''O. mytiloides'' Lamarck.

Distribution

In Australia it is found in bays, inlets and sheltered estuaries from Wingan Inlet in eastern Victoria, along the east coast of

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

, and north to Hervey Bay, Queensland, around northern Australia and south along the west coast to

Shark Bay Shark Bay () is a World Heritage Site in the Gascoyne region of Western Australia. The area is located approximately north of Perth, on the westernmost point of the Australian continent. UNESCO's listing of Shark Bay as a World Heritage S ...

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

. The spat for these oysters travels down the east coast of Australia on the East Australia Current. Also, a small population exists on the islands in the Furneaux archipelago in

Bass Strait Bass Strait () is a strait separating the island state of Tasmania from the Mainland Australia, Australian mainland (more specifically the coast of Victoria (Australia), Victoria, with the exception of the land border across Boundary Islet). The ...

, and in Albany on the south west coast of Western Australia, where they are farmed.

Ecology

Sydney rock oysters are capable of tolerating a wide range of salinities. They are usually found in the intertidal zone to below the low-water mark. Oysters are filter feeders, straining planktonic

alga Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular microalgae, suc ...

e from the water. Birds, fish,

stingray Stingrays are a group of sea Batoidea, rays, a type of cartilaginous fish. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (deepwate ...

s, mud crabs, and

starfish Starfish or sea stars are Star polygon, star-shaped echinoderms belonging to the class (biology), class Asteroidea (). Common usage frequently finds these names being also applied to brittle star, ophiuroids, which are correctly referred to ...

all eat Sydney rock oysters, with the Australian pied oystercatcher (''Haematopus longirostris'') being particularly fond of them. Selective breeding of farmed rock oysters has successfully bred for disease resistance to two protozoan diseases of oysters, namely, QX disease '' Marteilia sydneyi'' and winter mortality '' Bonamia roughleyi''.

Growth and reproduction

Sydney rock oysters are "broadcast spawners", that is, eggs and sperm are released into open water where fertilisation occurs. Within hours of fertilisation, the eggs develop into free-swimming

planktonic Plankton are the diverse collection of organisms that drift in water (or air) but are unable to actively propel themselves against currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they pro ...

larvae A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect developmental biology, development such as insects, some arachnids, amphibians, or cnidarians typical ...

. The larvae swim in estuarine and coastal waters for up to three weeks, during which they develop transparent shells and retractable feet. The larvae then settle on clean substrates using their feet to find suitable sites. The larval foot is resaborbed once the larva is attached. The shell darkens and the small animal takes on the appearance of an adult oyster. Growth rates vary with local conditions, but they generally reach in three years. Sydney rock oysters may change sex during life. Many individuals start out as males and later change to females. About 60% of prime eating oysters are female. Selective breeding has reduced the time to market size from three to two years.

Human use

Commercial aquaculture industry

Sydney rock oyster on half shell with two empty shells

A substantial commercial oyster farming industry is found in New South Wales and southern Queensland, with a small, emerging industry in

Albany, Western Australia Albany ( ; ) is a port city in the Great Southern region in the Australian state of Western Australia, southeast of Perth, the state capital. The city centre is at the northern edge of Princess Royal Harbour, which is a part of King G ...

. The industry produces a gourmet product and provides employment in isolated coastal communities. In Australia, oysters in peak flesh condition (i.e. spawning condition) are preferred for the half-shell trade. The species was once extensively farmed in the Georges River estuary, but has not been since 2023. The species was once farmed in New Zealand. Oyster farmers there switched to Pacific Oysters, after faster-growing wild Pacific Oysters largely took over the fishery.

Consumption

Sydney rock oysters are best consumed when freshly shucked, but do have a good shelf life when kept whole, of up to 14 days providing they are kept at the correct temperature and handled safely.

Notes

References

External links

CIESM page on oyster species in the Mediterranean
* CC-By-SA">Creative_Commons_license.html" ;"title="/nowiki>Creative Commons license">CC-By-SA/nowiki> * https://www.dpi.nsw.gov.au/content/research/areas/aquaculture/outputs/2008/nell Retrieved 7 April 2022 {{Taxonbar">from1=Q61681722 glomerata Commercial molluscs Australian cuisine Australian cuisine">Commercial molluscs Australian cuisine Bivalves of Australia Bivalves of New Zealand">Bivalves of Australia">Australian cuisine">Commercial molluscs Australian cuisine Bivalves of Australia Bivalves of New Zealand Fauna of Western Australia Bivalves described in 1850 Taxa named by Augustus Addison Gould