Portuguese oyster

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Portuguese oyster
Crassostrea angulata-V.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Ostreida
Family: Ostreidae
Genus: Crassostrea
Species:
C. angulata
Binomial name
Crassostrea angulata
(Lamarck, 1819)

The Portuguese oyster, Crassostrea angulata, is a species of oyster found in the southwest Iberian Peninsula, closely related to the Pacific oyster. Although first identified as a native European species, genetic studies have suggested the Portuguese oyster originated from the Pacific coast of Asia [1] [2] [3] and was introduced to Europe by Portuguese trading ships in the 16th century. The species is usually found in coastal river mouths and estuaries.

Contents

Taxonomy

Crassostrea angulata was first described by the French naturalist Jean-Baptiste Lamarck in 1819. It belongs to the phylum Mollusca, class Bivalvia, order Ostreoida, and family Ostreidae. The genus Crassostrea contains several other important oyster species, including the Pacific oyster (C. gigas) and the American oyster (C. virginica). [4]

Morphology

The Portuguese oyster has a shell that is roughly triangular in shape, with a maximum length of 10-15 cm. The shell is composed of two valves that are joined by a hinge ligament. The exterior of the shell is generally rough and irregular, with prominent ridges and grooves. The interior of the shell is smooth and pearlescent, with a deep cup-shaped depression that holds the soft body of the animal. [4]

Habitat

The Portuguese oyster is typically found in intertidal and subtidal habitats, where it attaches itself to hard substrates such as rocks, boulders, and other oyster shells. It is a euryhaline species, meaning that it is able to tolerate a wide range of salinity levels. In its native range, it occurs in estuaries and bays with a salinity range of 25-35 ppt. [1]

Ecology

The Portuguese oyster is a filter feeder, using its gills to extract phytoplankton and other small particles from the surrounding water. It is an important ecological species, providing habitat and food for a wide range of other organisms. It is also an important bioindicator species, as it is sensitive to changes in water quality and pollution. [1] [3]

Fisheries

The Portuguese oyster has been an important commercial species in Europe for centuries. It is cultivated using a variety of methods, including bottom culture, floating culture, and rack and bag culture. [3] In recent years, the species has been impacted by the spread of a parasitic disease known as Gill Disease, which has caused significant mortality in oyster populations in France, Spain, and Portugal. This causes gill erosion corresponding with high mortality rates of the oyster in certain populations. [5]

Commercial Value

Prior to decimation by iridoviral disease in 1969, [5] C. angulata was extensively cultivated in France and Portugal as part of the edible oyster industry. The Pacific oyster, which is more resistant to the disease, was introduced in the 1970s and has since replaced C. angulata as the main commercial species. The Portuguese oyster is cultured commercially in Taiwan.

Conservation Status

The Portuguese oyster is listed as a species of "Least Concern" on the IUCN Red List, as it is considered to be a widespread and abundant species with no known major threats. [6] However, local populations have been impacted by overfishing, habitat loss, and disease outbreaks, and conservation efforts are ongoing to protect and restore oyster populations in affected areas. [7]

Related Research Articles

<span class="mw-page-title-main">Estuary</span> Partially enclosed coastal body of brackish water

An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environments and are an example of an ecotone. Estuaries are subject both to marine influences such as tides, waves, and the influx of saline water, and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world.

<span class="mw-page-title-main">Oyster</span> Variety of families of Mollusc

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 not all oysters are in the superfamily Ostreoidea.

<span class="mw-page-title-main">Eastern oyster</span> Species of bivalve

The eastern oyster —also called the Atlantic oyster, American oyster, or East Coast oyster—is a species of true oyster native to eastern North and South America. Other names in local or culinary use include the Wellfleet oyster, Virginia oyster, Malpeque oyster, Blue Pointoyster, Chesapeake Bay oyster, and Apalachicola oyster. C. virginica ranges from northern New Brunswick south through parts of the West Indies to Venezuela. It is farmed in all of the Maritime provinces of Canada and all Eastern Seaboard and Gulf states of the United States, as well as Puget Sound, Washington, where it is known as the Totten Inlet Virginica. It was introduced to the Hawaiian Islands in the nineteenth century and is common in Pearl Harbor.

<i>Crassostrea</i> Genus of bivalves

Crassostrea is a genus of true oysters containing some of the most important oysters used for food. Some species in the genus have been moved to the genus Magallana.

<span class="mw-page-title-main">Ostreidae</span> Family of molluscs

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.

Perkinsus marinus is a species of alveolate belonging to the phylum Perkinsozoa. It is similar to a dinoflagellate. It is known as a prevalent pathogen of oysters, causing massive mortality in oyster populations. The disease it causes is known as dermo or perkinsosis, and is characterized by the degradation of oyster tissues. The genome of this species has been sequenced.

<span class="mw-page-title-main">Pacific oyster</span> Species of bivalve

The Pacific oyster, Japanese oyster, or Miyagi oyster, is an oyster native to the Pacific coast of Asia. It has become an introduced species in North America, Australia, Europe, and New Zealand.

<span class="mw-page-title-main">Oyster farming</span> Commercial growing of oysters

Oyster farming is an aquaculture practice in which oysters are bred and raised mainly for their pearls, shells and inner organ tissue, which is eaten. Oyster farming was practiced by the ancient Romans as early as the 1st century BC on the Italian peninsula and later in Britain for export to Rome. The French oyster industry has relied on aquacultured oysters since the late 18th century.

<i>Ostrea edulis</i> Species of oyster

Ostrea edulis, commonly known as the European flat oyster, is a species of oyster native to Europe. In Britain and Ireland, regional names include Colchester native oyster, mud oyster, or edible oyster. In France, Ostrea edulis are known as huîtres plates except for those that come from the Belon River estuary in Brittany, France, which are known as Belons.

<span class="mw-page-title-main">Netarts Bay</span>

Netarts Bay is an estuarine bay on the northern Oregon Coast of the U.S. state of Oregon, located about 5 miles (8.0 km) southwest of Tillamook. The unincorporated community of Netarts is located on the north end of the bay and Netarts Bay Shellfish Preserve, managed by Oregon Department of Fish and Wildlife, is located on the south side of the bay. The sand spit on the west side of Netarts bay is part of Cape Lookout State Park.

<i>Ostrea lurida</i> Species of bivalve

Ostrea lurida, common name the Olympia oyster, after Olympia, Washington in the Puget Sound area, is a species of edible oyster, a marine bivalve mollusk in the family Ostreidae. This species occurs on the northern Pacific coast of North America. Over the years the role of this edible species of oyster has been partly displaced by the cultivation of non-native edible oyster species.

Haplosporidium nelsoni is a pathogen of oysters that originally caused oyster populations to experience high mortality rates in the 1950s, and still is quite prevalent today. The disease caused by H. nelsoni is also known as MSX. MSX is thought to have been introduced by experimental transfers of the Pacific oyster, which is resistant to this disease.

<span class="mw-page-title-main">Oyster reef restoration</span> Process of rebuilding or restoring of oyster reefs

Oyster reef restoration refers to the reparation and reconstruction of degraded oyster reefs. Environmental changes, modern fishing practices, over harvesting, water pollution, and other factors, have resulted in damage, disease, and ultimately, a large decline in global population and prevalence of oyster habitats. Aside from ecological importance, oyster farming is an important industry in many regions around the world. Both natural and artificial materials have been used in efforts to increase population and regenerate reefs.

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<i>Saccostrea cucullata</i> Species of bivalve

Saccostrea cucullata, the hooded oyster or Natal rock oyster, is a species of rock oyster found mainly in the Indo-Pacific Ocean.

<span class="mw-page-title-main">Shell growth in estuaries</span>

Shell growth in estuaries is an aspect of marine biology that has attracted a number of scientific research studies. Many groups of marine organisms produce calcified exoskeletons, commonly known as shells, hard calcium carbonate structures which the organisms rely on for various specialized structural and defensive purposes. The rate at which these shells form is greatly influenced by physical and chemical characteristics of the water in which these organisms live. Estuaries are dynamic habitats which expose their inhabitants to a wide array of rapidly changing physical conditions, exaggerating the differences in physical and chemical properties of the water.

The Suminoe oyster, is a species of true oyster which inhabits intertidal hard grounds and substrate, as well as muddy creeks of warm estuaries throughout the western Pacific. It is large and flat in appearance and almost identical in gross morphology to Crassostrea virginica.

<span class="mw-page-title-main">Oyster reef</span>

The term oyster reef refers to dense aggregations of oysters that form large colonial communities. Because oyster larvae need to settle on hard substrates, new oyster reefs may form on stone or other hard marine debris. Eventually the oyster reef will propagate by spat settling on the shells of older or nonliving oysters. The dense aggregations of oysters are often referred to as an oyster reef, oyster bed, oyster bank, oyster bottom, or oyster bar interchangeably. These terms are not well defined and often regionally restricted.

<i>Crassostrea rhizophorae</i> Species of bivalve

Crassostrea rhizophorae, also known as the mangrove cupped oyster, is a species of bivalves in the family Ostreidae. C. rhizophorae is one of the predominating oyster species in the South Atlantic, specifically in Central and South America. It is often found in the vast mangrove ecosystem along the coast of Brazil.

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References

  1. 1 2 3 , Michinina S and Rebordinos L. 1997. Genetic differentiation in marine and estuarine natural populations of Crassostrea angulata. Marine Ecology Progress Series.
  2. , Boudry P et al. 1998. Differentiation between populations of the Portuguese oyster, Crassostrea angulata (Lamark) and the Pacific oyster, Crassostrea gigas (Thunberg), revealed by mtDNA RFLP analysis. Journal of Experimental Marine Biology and Ecology.
  3. 1 2 3 , Lapegue S, et al. 2004. Evidence for the presence of the Portuguese oyster, Crassostrea angulata, in northern China. Journal of Shellfisheries Research.
  4. 1 2 Lu, Jia-chi (2012). "The growth and reproduction of the Portuguese oyster, Crassostrea angulata, in Taixi and Qigu, Taiwan".{{cite journal}}: Cite journal requires |journal= (help)
  5. 1 2 , Gill Disease of Portuguese oysters. Fisheries and Oceans Canada.
  6. "IUCN Red List of Threatened Species". 2023.
  7. "Fish and Overfishing". Our World in Data. Retrieved 2023-04-14.