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| ==Biology== | ==Biology== | ||
| The sexes are separate in ''Pteria sterna'' and the oysters become mature |
The sexes are separate in ''Pteria sterna'' and when the oysters become mature they have an average shell size of around {{convert|117|mm|1|abbr=on}} for females and {{convert|106|mm|1|abbr=on}} for males. Spawning is synchronised in any one locality and depends on the water temperature and the availability of food. In ] lagoon it takes place between October and April, commencing as the water temperature falls.<ref name=Hernandez>{{cite journal |author=Hernandez-Olalde, Liliana; Garcia-Dominguez, Frederico; Arellano-Martinez, Marcial; Ceballos-Vasquez, Bertha Patricia |year=2007 |title=Reproductive cycle of the pearl oyster ''Pteria sterna'' (Pteriidae) in the Ojo de Liebre lagoon, BCS, México |journal=Journal of Shellfish Research |volume=26 |issue=2 |pages=543–548 |doi=10.2983/0730-8000(2007)262.0.CO;2 }}</ref> | ||
| ==Pearl culture== | ==Pearl culture== | ||
Revision as of 15:32, 11 April 2014
| Pteria sterna | |
|---|---|
| |
| Pteria sterna with pearls | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Order: | Pterioida |
| Family: | Pteriidae |
| Genus: | Pteria |
| Species: | P. sterna |
| Binomial name | |
| Pteria sterna (Gould, 1851) | |
| Synonyms | |
| |
Pteria sterna, commonly known as the rainbow-lipped pearl oyster or the Pacific wing-oyster, is a species of marine bivalve mollusc in the family Pteriidae, the pearl oysters. This oyster can be found in shallow water along the tropical Pacific coast of America, its range extending from Baja California to northern Peru.
History
Fragments of shell ornaments made from the nacre of the Pacific wing-oyster have been found at ancient burial sites in Mexico, probably belonging to the indigenous Seri people of the Sonora region. This oyster has been the subject of a pearl fishery in the Gulf of California since before the arrival of Fernando Cortez in 1535; the Spaniards quickly appreciated the value of the harvest and three years later declared the gathering of oysters to be a right of the Spanish crown. By the 1840s, the export of the shells was as valuable as the pearls extracted from them, and in 1874, compressed air diving equipment made harvesting the oysters easier. By the early 1900s, some 200,000 to 500,000 oysters (including another species, Pinctada mazatlanica), were being harvested annually. This over-exploitation caused populations of the oyster to become depleted and in 1940 the fishery was closed by the Mexican Government, a ban that still remains in force.
Biology
The sexes are separate in Pteria sterna and when the oysters become mature they have an average shell size of around 117 mm (4.6 in) for females and 106 mm (4.2 in) for males. Spawning is synchronised in any one locality and depends on the water temperature and the availability of food. In Ojo de Liebre lagoon it takes place between October and April, commencing as the water temperature falls.
Pearl culture
The Pacific wing-oyster naturally produces grey, pink, golden, green and purplish pearls. With the dwindling of the number of wild oysters, efforts to farm this species on a commercial scale to produce pearls have been made. The production of cultured pearls requires the grafting of a pearl nucleus, together with a portion of mantle tissue from a donor into a recipient oyster. The culture of round pearls in Pacific wing-oysters is technically hard; the oysters are small and the shell thin, the shape of the shell makes the seeding operation difficult and the pearl sac is wide at the base which means that the graft may shift around. With experience, technicians gain expertise in seeding and yields can be high, with pearls reaching 13 mm (0.5 in) in diameter.
The quality of the donor mantle tissue affects the quality of the pearl. The grafting process normally involves killing the donor oyster, but it has been found that if it is instead anaesthetised before the tissue is surgically removed, regeneration of the missing mantle tissue takes place over the course of a few weeks. In this way, high quality donor oysters can be preserved as future breeding stock.
References
- ^ Tëmkin, Ilya (2014). "Pteria sterna (Gould, 1851)". WoRMS. World Register of Marine Species. Retrieved 2014-02-14.
- ^ Nava, M.; Arizmendi, E.; Farell, S.; McLaurin, D. (2000). "Evaluation of success in the seeding of round nuclei in Pteria sterna (Gould 1851), a new species in pearl culture". SPC Pearl Oyster Information Bulletin. 14.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Southgate, Paul; Lucas, John (eds.) (2011). The pearl oyster. Elsevier. pp. 31–34. ISBN 9780080931777.
{{cite book}}:|first2=has generic name (help) - ^ Hernandez-Olalde, Liliana; Garcia-Dominguez, Frederico; Arellano-Martinez, Marcial; Ceballos-Vasquez, Bertha Patricia (2007). "Reproductive cycle of the pearl oyster Pteria sterna (Pteriidae) in the Ojo de Liebre lagoon, BCS, México". Journal of Shellfish Research. 26 (2): 543–548. doi:10.2983/0730-8000(2007)26[543:RCOTPO]2.0.CO;2.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Acosta-Salmón, Héctor; Martınez-Fernández, Erika; Southgate, Paul C. (2004). "A new approach to pearl oyster broodstock selection: can saibo donors be used as future broodstock?". Aquaculture. 231 (1–4): 235–214. doi:10.1016/j.aquaculture.2003.08.022.
{{cite journal}}: CS1 maint: multiple names: authors list (link)