The
Sydney rock oyster,
Saccostrea glomerata, formerly known as
Saccostrea commercialis, is an
oysterThe word oyster is used as a common name for a number of distinct groups of bivalve molluscs which live in marine or brackish habitats. The valves are highly calcified....
species endemic to
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and
New ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. In Australia it is found in bays, inlets and sheltered estuaries from
Wingan InletWingan Inlet is an inlet within the Croajingolong National Park, in East Gippsland, Victoria, Australia. It features a ranger-managed camping ground, about an hour's drive from the nearest town, Cann River, along a notoriously rough stretch of dirt road...
in eastern
VictoriaVictoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
, along the east coast of
New South WalesNew South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
and up to Hervey Bay
QueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
., around northern Australia and down the west coast to
Shark BayShark Bay is a World Heritage listed bay in Western Australia. The term may also refer to:* the locality of Shark Bay, now known as Denham* Shark Bay Marine Park* Shark Bay , a shark exhibit at Sea World, Gold Coast, Australia* Shire of Shark Bay...
in
Western AustraliaWestern Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
. There is also a small introduced population on
Flinders IslandFlinders Island may refer to:In Australia:* Flinders Island , in the Furneaux Group, is the largest and best known* Flinders Island * Flinders Island , in the Investigator Group* Flinders Island...
, in
Bass StraitBass Strait is a sea strait separating Tasmania from the south of the Australian mainland, specifically the state of Victoria.-Extent:The International Hydrographic Organization defines the limits of the Bass Strait as follows:...
,
TasmaniaTasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
and in Albany on the south west coast of
Western AustraliaWestern Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
, where they are farmed. In New Zealand, where the species is not farmed, it is known as the
New Zealand rock oyster. The Sydney rock oyster is closely related to
Saccostrea cucullata, or hooded oyster, which is common on Indo-Pacific rocky shores.
Sydney rock oysters are capable of tolerating a wide range of salinities (halotolerant). They are usually found in the intertidal zone to 3 metres below the low water mark.
Breeding
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
larvaA larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e. The larvae swim in estuarine and coastal waters for up to 3 weeks, during which time they develop transparent shells and a retractable foot. The larvae then settle on a clean substrate using the foot to find a suitable site. The foot is resorbed 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 50 g in 3 years. Sydney rock oysters may change sex during life. Many 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 3 to 2 years. There has also been great success in selection for disease resistance to two protozoan diseases of oysters, namely, QX disease
Marteilia sydneyi and winter mortality
Bonamia roughleyi.
Oysters are filter feeders, straining planktonic algae from the water. Birds, fish,
stingrayThe stingrays are a group of rays, which are cartilaginous fishes related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes, and consist of eight families: Hexatrygonidae , Plesiobatidae , Urolophidae , Urotrygonidae , Dasyatidae , Potamotrygonidae The...
s,
mud crabMud crab may refer to any crab that lives in or near mud, such as:*Scylla serrata, also called mangrove crab and black crab.*Scylla tranquebarica, another variety of the mangrove crab.*Scylla paramamosain...
s and starfish all eat Sydney rock oysters, with the Australian Pied Oystercatcher being particularly fond of them.
Commercial industry
There is a substantial commercial oyster farming industry in New South Wales and southern Queensland and a small emerging industry in
Albany, Western AustraliaAlbany is a port city in the Great Southern region of Western Australia, some 418 km SE of Perth, the state capital. As of 2009, Albany's population was estimated at 33,600, making it the 6th-largest city in the state....
. The industry produces a gourmet product and provides employment in isolated coastal communities. In Australia, oysters in peak meat condition (i.e. spawning condition) are preferred for the half-shell trade.
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 (10 to 15 degrees Celsius; 32 to 41 °F) and handled safely.
External links