The list of oyster species (Ostreidae) in Vietnam is reported to have about 31 species (Hylleberg & Kilburn, 2003), of which some species are synonyms and some species are being cultured but the source of the seed is not native to the Vietnamese sea such as Pacific oyster (Magallana gigas), Hong Kong oyster (Magallana hongkongensis). To identify the difference between the oyster species being cultured by external morphology is not easy for farmers and consumers. This report has revised and updated the scientific names, using the oyster adductor muscle marks as a quick identification feature for the characteristic morphological differences between species.
- Magallana ariakensis (Fujita, 1913);
- Magallana belchery (Sowerby, 1871);
- Magallana bilineata (Röding, 1798);
- Magallana gigas (Thunberg, 1793);
- Magallana hongkongensis (Lam, Morton, 2003).
Documents and research methods on oyster species currently farmed in Vietnam
Using documents and research results of authors published on species composition Oysters in Vietnam’s waters (Table 1). Updated new scientific names according to WoRMS-World Register of Marine Species (www.marinespecies.org/aphia).
Collected specimens of species being cultured in the provinces: Ca Mau, Tra Vinh, Ben Tre, Ho Chi Minh City (Can Gio), Ba Ria-Vung Tau, Ninh Thuan, Khanh Hoa, Thua Thien – Hue, Quang Ninh.
Identify oysters according to the morphological comparison method of the group of authors (Lam & Morton, 2003, 2004, and 2006). In this study, we used the characteristics of the adductor muscle of oyster species as a distinguishing feature between the species being farmed in Vietnam (Figure 1).
Specimen preservation: Dried oyster shells were kept at the Museum of the Institute of Oceanography and at the Culture Technology Department
The composition of the oyster species being farmed has been published and need to update the scientific name
Table 1. Composition of oyster species currently farmed in Vietnam
| No. | Scientific name published, year of publication | Author | Scientific name updated, adjusted |
| 1 | Crassostrea belcheri (Sowerby, 1871) | Ngo Anh Tuan et al., 2005 | Magallana belcheri (Sowerby, 1871) |
| 2 | Crassostrea belcheri Sowerby, 1871) | Ngo Anh Tuan et al., 2008 | Magallana belcheri (Sowerby, 1871) |
| 3 | Crassostrea rivulatis (Gould, 1861) | Ngo Thi Thu Thao & Tran Tuan Phong, 2012 | Magallana ariakensis (Fujita, 1913) |
| 4 | Crassostrea belcheri (Sowerby, 1871) | Ngo Thi Thu Thao et al. 2018 | Magallana belcheri (Sowerby, 1871) |
| 5 | Crassostrea rivulatis (Gould, 1861) | Pham Duc Minh et al., 2016 | Magallana ariakensis (Fujita, 1913) |
| 6 | Crassostrea rivulatis (Gould, 1861) | Tran Quoc Dung et al., 2018 | Magallana ariakensis (Fujita, 1913) |
| 7 | Crassostrea lugubris (Sowerby, 1871). | Cao Van Nguyen& Nguyen Tac An, 2006 | Magallana bilineata (Röding, 1798) |
| 8 | Crassostrea lugubris (Sowerby, 1871) | Magallana bilineata (Röding, 1798) | |
| 9 | Crassostrea gigas Thǖnberg, 1793 | Cao Van Nguyen et al., 2016 |
Characteristics of the adductor cortical muscle of 5 oyster species being farmed commercially in Vietnam
Table 2. Distinctive characteristics of the adductor muscle marks of 5 oyster species being farmed
< table style="border-collapse: collapse; width: 50.1088%; height: 206px;"> Species name Characteristics of the adductor muscle 1 Estuary oyster, Magallana
ariakensis (Fujita, 1913) Tongue form sickle, black, located posteriorly on the
abdomen (Figure 2). 2 Hong Kong oyster, Magallana
hongkongensis (Lam & Morton,
2003) D-shaped, dark brown, located in between the center
of the shell longitudinally and offset to the posterior aspect of the abdomen
(Figure 3). 3 White oyster, Magallana belcheri
(Sowerby II, 1871) Sickle-shaped, white, distinct from other
species (Figure 4). 4 Milk oyster, Magallana bilineata
(Röding, 1798) Kidney-shaped, dark purple (black) or pink
on both shells, located ventrally (Figure 5). 5 Pacific Oyster, Magallana
gigas (Thunberg, 1793) The adductor muscle mark is large and elongated, usually pink or dark purple, located on the posterior side of the back, and occasionally has purple growth lines (Figure 6) on the adductor muscle mark. . Estuary oysters – red meat oysters< /h3>
STT
ariakensis (Fujita, 1913)
abdomen (Figure 2).
hongkongensis (Lam & Morton,
2003)
of the shell longitudinally and offset to the posterior aspect of the abdomen
(Figure 3).
(Sowerby II, 1871)
species (Figure 4).
(Röding, 1798)
on both shells, located ventrally (Figure 5).
gigas (Thunberg, 1793)
Taxonomy of oyster species currently farmed in Vietnam
Estuary oysters – red meat oysters< /h3>- Suborder Ostreina Férussac, 1822
- Superfamily Ostreoidea Rafinesque, 1815
- Family Ostreidae Rafinesque, 1815
- Subfamily Crassostreinae Torigoe, 1981
- Magallanas Salvi & Mariottini, 2016
- Oyster Magallana ariakensis (Fujita, 1913), Figure 2
- Common name: Estuary oyster, red meat oyster.
- English name: Suminoe oyster-red meat oyster.
- Synonyms: Crassostrea paulucciae Crosse, 1870; Ostrea palmipes Soweby, 1871; Ostrea rivularis Lischke, 1869; Ostrea ariakensis Fujita, 1913. Crassostrea ariakensis (Fujita, 1913 )
- Quick identification features: The shell is usually round and egg-shaped, the finished oyster is large in size, from 100 – 110 mm. Shell height and length are 80 – 85 mm, the growth plates are arranged concentric. Inside the shell is white, the adductor muscle mark is crescent-shaped, black, or brown, located towards the back of the abdomen
- World distribution: Occurs naturally in Japan, along along the gulfs and estuaries of China (Lam, Morton, 2003)
- Distribution in Vietnam: Found at the mouth of the Chanh River, Quang Yen town – Quang Ninh province. This species is currently being raised on floating rafts in Song Chanh (Lien Hoa commune, Quang Yen town, Quang Ninh). The origin of the breed is imported from China.
- Current taxonomic status: Classification In the current taxonomy, the oyster species in the genus Crassostrea are replaced by the genus name Magallana (Salvi, Mariottini, 2016). In Vietnam, in previous documents and reports on estuarine oysters, the name Crassostrea rivularis is often used. Above In the field, this species is usually only found in Bach Dang River, Chanh River – Quang Yen (Quang Ninh).
Hong Kong Oyster Magallana hongkongensis
- Hong Kong oyster Magallana hongkongensis (Lam & Morton, 2003), Figure 3
- Common name: Hong Kong oyster, white meat oyster.
- English name: Hong Kong cultured oyster-white meat-oyster
- Synonym: Crassostrea hongkongensis (Lam & Morton, 2003)
- Quick identification characteristics: The shell is elongated, thick and hard, the finished oyster has a large size of 100-125 mm in shell height and 75-80 mm in length. The adductor muscle is D-shaped, dark brown, located in the center of the shell longitudinally and slightly offset to the back of the abdomen.
- Distribution in the world: In Hong Kong Bay, in the intertidal and subtidal zones, it is endemic to the East Sea (Lam & Morton, 2003).
- Distribution in Vietnam: Hong Kong oysters are imported into Vietnam.
- Current farming status: This species is being farmed in floating rafts with the estuarine oyster species Magallana ariakensis in Song Chanh, Lien Hoa commune, Quang Yen town, Quang Ninh, the origin of the farmed breed is imported from China.
White oyster Magallana belcheri
- White oyster Magallana belcheri (Sowerby II, 1871), Figure 4
- Common name: White closed-shell oyster (white oyster).
- English name: Belcher’s oyster (Soweby, 1870), white scar oyster.
- Synonym: Ostrea belcheri Sowerby, 1871; Crassostrea belcheri Sowerby, 1871).
- Quick identification: Oysters are large, have thick shells, and are elongated oval or ovoid, or nearly triangular in shape. The left shell is usually more deeply concave than the right shell, and the mouth rim has no teeth (chomata). The white, crescent-shaped adductor muscle mark is the two main identifying features of the species.
- World distribution: Found in the Gulf of Siam, estuaries of Thailand, Malaysia,
Singapore, Hong Kong, coastal areas of Sumatra, Java-Indonesia, Sulu, Celebes,
Philippines, Pakistan waters (Bussarawit, Cedhagen, 2010).
- Distribution in Vietnam: White oyster Magallana belcheri, found in the Long Son estuary, Ba Ria-Vung Tau province, Can Gio coastal area, Ho Chi Minh City (Ngo Anh Tuan et al., 2005), canals of coastal districts of Ben Tre (Ngo Thi Thu Thao et al., 2018). In this study, it was also found in coastal canals of Binh Dai and Ba Tri districts, Ben Tre province; estuaries of Duyen Hai town, Tra Vinh province; canals of Ganh Hau town, Bac Lieu province; canals and creeks of Dat Mui commune, Ngoc Hien district, Ca Mau province; coastal areas of Ba Hon, Kien Giang province.
- Current farming status: White oyster Magallana belcheri is a popular farming species in the Gulf of Thailand, Malaysia, and Cambodia (Bussarawit, Cedhagen, 2010). In Vietnam, oysters are naturally distributed in coastal mangrove forests of the Eastern and Southwestern provinces. This species is currently being farmed in Cha Va River in Long Son Commune, Vung Tau City, Ba Ria Vung Tau Province; in coastal areas of Can Gio District, Ho Chi Minh City; in canals in Thua Duc Commune (Binh Dai District), Bao Thuan Commune (Ba Tri District), Ben Tre Province; canals in Duyen Hai Town, Tra Vinh Province; canals in Bac Lieu, Soc Trang, and Ca Mau Provinces. The source of the breed is from natural sources, and it is farmed commercially using hanging racks and floating rafts. In this study, we consider the oyster Crassostrea rivularis collected in Bac Lieu by the authors (Ngo Thi Thu Thao & Tran Tuan Phong, 2012; Pham Duc Minh et al. 2016) as the species Magallana belcheri.
Milk oyster Magallana bilineata
- Milk oyster Magallana bilineata (Röding, 1798), Figure 5
- Common name: Tropical oyster, black oyster, spoon oyster, milk oyster.
- English name: Slipper-shaped oyster, black-scar oyster.
- Synonym: Ostrea bilineata Röding, 1798; Ostrea lugubris Sowerby, 1871; Crassostrea lugubris (Sowerby, 1871); Ostrea iredalei Faustino, 1932; Crassostrea iredalei, (Faustino, 1932)
- Quick identification characteristics: Thick and hard shell, deeply concave shell, inside the shell edge is usually dark brown, finished oyster size according to shell height from 75-80 mm, length from 45-55 mm. The black or pink kidney-shaped adductor muscle mark is the main identifying feature of the species.
- Distribution in the world: East Sea, Andaman Sea, Gulf of Thailand, Papua New Guinea, Philippines (Bussarawit, Cedhagen, 2010).
- Distribution in Vietnam: Found in Lang Co lagoon, Thua Thien-Hue; sea area of An Hoa commune, Quang Nam; Thi Nai lagoon, Binh Dinh; Nha Phu lagoon, Khanh Hoa; Nai lagoon, Ninh Thuan (Cao Van Nguyen et al. 2014).
- Current farming status: This species is currently being farmed widely in the Central region such as Lang Co lagoon, Thua Thien-Hue; Thi Nai lagoon, Binh Dinh; Song Cau sea area, Phu Yen; Nha Phu lagoon, Khanh Hoa; Nai lagoon, Ninh Thuan. Breeding sources are from natural sources, commercial farming by pole farming, hanging rack farming. In this study, we consider the oyster Crassostrea rivularis sampled in Lang Co Bay by the authors (Tran Quoc Dung et al., 2018) as Magallana bilineata oyster.
Pacific oyster Magallana gigas
- Pacific oyster Magallana gigas (Thunberg, 1793), Figure 6
- Common name: Pacific oyster.
- English name: Pacific oyster.
- Synonym: Ostrea gigas Thunberg, 1793; Crassostrea gigas (Thunberg, 1793).
- Left shell is deeply concave, right shell is flat and slightly curved. Inside the white shell, the adductor muscle mark is large and long, often pink, dark purple, located on the back side, on the adductor muscle mark there are sometimes purple growth lines, the adductor muscle position is in the middle of the shell and is offset towards the back.
- Distribution in the world: Found in the seas of Japan, Korea, Maritime Russia, Yellow Sea-China.
- Distribution in Vietnam: Pacific oysters were imported to Vietnam from Taiwan (China) in early 2006 and were first farmed in Bai Tu Long Bay.
- Quick identification characteristics: Long, gray-green shells, with high edges (notches) on the edges of the shell.
- Current farming status: Pacific oysters are a popular farming species in Vietnam in bays and straits in the Central region such as Thi Nai lagoon (Binh Dinh), Song Cau sea area (Phu Yen), Nha Phu lagoon, Thuy Trieu lagoon (Khanh Hoa), Nai lagoon (Ninh Thuan), Ha Long bay, Bai Tu Long bay (Quang Ninh). Breeding from artificial reproduction sources in the country. Oysters have a fast growth rate, have advantages over other oyster species such as large body size and mass, and stable breeding sources.
Conclusion
Five oyster species currently cultured in Vietnam have been revised and updated: estuarine oysters (Magallana ariakensis (Fujita, 1913)), Hong Kong oysters (Magallana hongkongensis (Lam & Morton, 2003)), white oysters (Magallana belcheri (Sowerby, 1871)), milk oysters (Magallana bilineata (Röding, 1798)), Pacific oysters (Magallana gigas (Thunberg, 1793)).
Source: Editing and updating scientific names of oyster species being farmed in Vietnam’s seas (Cao Van Nguyen – Bui Quang Nghi, Institute of Oceanography, Vietnam Academy of Science and Technology)
