The dredge oyster, Bluff oyster or Chilean oyster (''Ostrea chilensis''), is also known in

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

as ''ostra verde'', is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of flat oyster. It is a marine

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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 ...

Distribution

This species is

native Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...

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 Chile, its range limit is from

Chiloé Island Chiloé Island (, , ), also known as Greater Island of Chiloé (''Isla Grande de Chiloé''), is the largest island of the Chiloé Archipelago off the west coast of Chile, in the Pacific Ocean. The island is located in southern Chile, in the Los L ...

, Los Lagos region to Guaitecas Islands, Aysén region. Practically, nowadays it only exists in the wild in one natural bank, Pullinque, a sector located in the Quetalmahue Gulf of Ancud which was declared a genetic reserve in 1982, and as a marine reserve in 2003. In the 1960s, the species was deliberately introduced to the

Menai Strait The Menai Strait () is a strait which separates the island of Anglesey from Gwynedd, on the mainland of Wales. It is situated between Caernarfon Bay in the south-west and Conwy Bay in the north-east, which are both inlets of the Irish Sea. The s ...

off

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

by the Fisheries Laboratory, Conwy. This was an experiment to determine if the oyster could be an alternative to the native ''

Ostrea edulis ''Ostrea edulis'', commonly known as the European flat oyster, is a species of oyster native to Europe. In Great Britain and Ireland, localized names include Colchester native oyster, mud oyster, or edible oyster. In France, ''Ostrea edulis'' are ...

'' oysters in fisheries. The species was found to be unsuitable because of low

recruitment Recruitment is #Process, the overall process of identifying, sourcing, screening, shortlisting, and interviewing candidates for Job (role), jobs (either permanent or temporary) within an organization. Recruitment also is the process involved in ...

and vulnerability to parasites and pathogens, and the experiment was abandoned. A self-sustaining population of ''O. chilensis'' remains, and has spread to other areas of the Menai Strait; it is regarded as an

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

Habitat

This bivalve is found from low tide to depths of up to 35 m. In Chile it lives attached to hard rocky or muddy bottoms, from intertidal to about 8 meters deep, in enclosed bays or areas protected from strong waves.

Description

Its length is up to 105 mm, width up to 70 mm, and inflation up to 33 mm. In Chile its maximum controlled length is 87 mm.

Commercial importance

In New Zealand, they are a prized delicacy, and harvested from March to August from the

Foveaux Strait Foveaux Strait ( ; ) is a strait that separates Stewart Island from the South Island of New Zealand. The width of the strait ranges from about , and the depth varies between . The strait was first charted by an American Seal hunting, sealer, O ...

oyster fishery, which centres on the town of Bluff (hence the local name). From the early 1980s, the fishery went into serious decline, due to the outbreak of an oyster parasite, ''Bonamia exitiosa'', with the disease killing an estimated billion oysters between 2000 and 2003. The population has been recovering since 2003, with fishermen voluntarily limiting the catch to half the allowable to aid the revival. In Chile, it has been harvested by the fishermen of Chiloé Island since ancient times, but the written and photographic information dates back to the mid-1800s. As Chile is the longest country in the world, the transportation of the harvested oysters by wooden-made ships, or by early trains in the early 1900s from the south (42°S) to the port of

Valparaíso Valparaíso () is a major city, Communes of Chile, commune, Port, seaport, and naval base facility in the Valparaíso Region of Chile. Valparaíso was originally named after Valparaíso de Arriba, in Castilla–La Mancha, Castile-La Mancha, Spain ...

, and then to the capital,

Santiago Santiago (, ; ), also known as Santiago de Chile (), is the capital and largest city of Chile and one of the largest cities in the Americas. It is located in the country's central valley and is the center of the Santiago Metropolitan Regi ...

, was complex; however, it got solved when the oysters were placed in barrels that were grated and jointed by quila, a kind of bamboo, and then filled with seawater. The trip lasted half a month. In the city of Ancud, Chiloé Island, the extraction of the oyster was banned even at that time (as in 1869 and then in 1874) due to its overexploitation, on the other hand its sale brought thousands of barrels, boxes and sacks of oysters to the capital to supply its great demand. The oysters was even kept in ponds for growing by Frenchmen, first b
Mr. Choloux
in Lechagua, Ancud, 1874 and later by the Solminihac family, formally with a concession in Quetalmahue, city of Ancud, in 1915. A couple of years later, in 1935, the Pullinque Oyster Station was built in Pullinque to try to cultivate the Chilean oyster, initiative that proved to be successful because it could provide with seeds for growth to other aquaculture centers that emerged during the agrarian reform period. The economy of Chilean oysters was severely hurt when the most powerful earthquake recorded happened in Valdivia, 1960 because the Pullinque Oyster Station was destroyed by it. Hence, the Corfo institution tried to bring-in the

Pacific oyster The Pacific oyster, Japanese oyster, or Miyagi oyster (''Magallana gigas'') is an oyster native to the Pacific coast of Asia. It has become an introduced species in North America, Australia, Europe, and New Zealand. Etymology The genus ''Magal ...

, but the intention was not recommended by the consulted experts, a decision that was respected by the national government. After the agrarian reform the commercial aquaculture started in the 80s, during the Civic-military dictatorship of Chile, according to

FAO The Food and Agriculture Organization of the United Nations; . (FAO) is a List of specialized agencies of the United Nations, specialized agency of the United Nations that leads international efforts to defeat hunger and improve nutrition ...

, since producers that were state-managed passed to be privately regulated, and also because many exotic species were tentative to introduce as culture options. Nowadays, its culture is successful in Chile with considerable tons exported, and consumed in some places and restaurants.

Other

Changes in river flows in Southland, due to farming and especially power generation, carrying less limestone deposits into the Strait, is therefore believed to have caused an increase in susceptibility to ''Bonamia'', as well as lower growth rates for some seasons in the past, but little evidence supports this and it seems only coincidental. Flawed discards practices in Chile during the 1890s of the small oysters ended up killing some oyster banks in Ancud. Particularly i
Corona lighthouse
and Quetalmahue Gulf; as the turbulence generated by the falling oysters resuspended the bottom sand, creating hypoxia conditions that did not allow the bivalves to breathe. Its

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the Co ...

name is .

References

External links

The National Centre for Fisheries & Aquaculture's page on Bluff oysters (''Tiostrea chilensis'')

JNCC: ''Tiostrea chilensis''
{{Taxonbar, from1=Q7808747, from2=Q14651290 Ostrea Molluscs of the Pacific Ocean Molluscs of Chile Bivalves of New Zealand Commercial molluscs New Zealand seafood Foveaux Strait Bivalves described in 1844 Taxa named by Heinrich Carl Küster