Pinctada margaritifera

Geographic Range

The black-lip pearl oyster, Pinctada margaritifera , has a wide geographic range extending from Baja California across the Indo-Pacific basin to the Red Sea, and northwards into the Eastern Mediterranean Sea. These regions enclose a number of suitable habitats for the oyster that feature coral reefs and lagoons. There are seven subspecies of Pinctada margaritifera ; each has a particular local distribution within the range of the species.

typica : Ryukyus, Taiwan, Australia, Micronesia and Melanesia; cumingi : Cook Islands, French Polynesia; mazalanica : Panama Bay, Baja California; erythraensis : Red Sea; persica : Persian Gulf; zanzibarensis : East Africa, Madagascar, and the Seychelle Islands; galtsoffi : Hawaiian Archipelago.

• Biogeographic Regions
• indian ocean
  • native native
• pacific ocean pacific ocean
  • native native
• mediterranean sea
  • native native

Habitat

Common habitats of Pinctada margaritifera include lagoons, bays, and sheltered reef areas to about 40 m depth. The oyster prefers oligotrophic coral reef waters with low turbidity. The oyster is epifaunal, using byssal threads to attach to hard surfaces such as rocks and the shells of conspecifics. The greatest density of P. margaritifera is in the atoll lagoons of eastern Polynesia, harboring some 7 million oysters with 5 million living in the Penrhyn lagoon and 2 million in Manihiki Lagoon.

• Habitat Regions
• tropical tropical
• saltwater or marine saltwater or marine

• Aquatic Biomes
• benthic benthic
• reef reef
• coastal coastal

• Other Habitat Features
• intertidal or littoral intertidal or littoral

Physical Description

Pinctada margaritifera features a black shell with a black, non-nacreous border, and is one of the largest species in its genus. In the Cook Islands and throughout most of French Polynesia, this species can grow to an average of 130 mm. From samples collected at Orpheus Island, Australia, individuals reached 146 mm in shell width, and had tissue mass ranging from 5.5 to 8.8 g. The oyster is known for producing black pearls cultured throughout a number of regions, including French Polynesia and the Cook Islands.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Development

The larval stage of Pinctada margaritifera can last for 16 to 30 days with an average daily growth rate of 3.7 to 5μm; development time is largely dependent on factors such as temperature and nutrition. The planktonic larva is known as a veliger, which develops a type of swimming mechanism called a ciliated velum also used for food transfer. At some point, the veliger will grow an appendage used to move across hard surfaces. Within the first 2 years of life, the shell may grow between 100 to 120 mm. At two years of age, the oyster has matured into an adult capable of reproducing.

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

All bivalves are broadcast spawners; gametes released by an individual may combine with those of multiple conspecifics.

Pinctada margaritifera is a protandrous hermaphrodite. It begins life as a male and later changes into a female. Pinctada margaritifera reaches sexual maturity around 2 years of age which is also around the same time the animal changes its sex. Pearl oysters reproduce by spawning, releasing their gametes into the open water for fertilization. Spawning is dependent on a number of factors which include salinity, currents, air exposure, and temperature. Oysters in temperate regions show more distinct seasonality in spawning, while tropical oysters have more of a year-round, intermittent schedule. Timing of spawning varies greatly from region to region. In the Red Sea, spawning occurs from March through September. However, there are two spawning seasons in Australia, one between July to August, and one in November.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sequential hermaphrodite
  • protandrous protandrous
• sexual sexual
• fertilization fertilization
  • external external
• broadcast (group) spawning
• oviparous oviparous

As broadcast spawners, there is no parental investment. Young develop independently in the water column, drifting as plankton.

• Parental Investment
• no parental involvement

Lifespan/Longevity

During the larval phase, Pinctada margaritifera is most vulnerable to predators and changing currents. After settlement, the rapid growth rate of the oyster significantly decreases its vulnerability to predators. On average, P. margaritifera has a lifespan of 15 years.

Behavior

After settlement as a postlarva, P. margaritifera spends a large amount of time seeking a compatible substrate (usually in a dark area) to bind to with its byssal threads. If such a substrate cannot be found, the oyster will migrate to a different location using its foot.

• Key Behaviors
• diurnal diurnal
• nocturnal nocturnal
• crepuscular crepuscular
• sessile sessile
• sedentary sedentary

Home Range

Black pearl oysters are sessile, and do not have a home range or territory.

Communication and Perception

Little is known about communication in Pinctada margaritifera . Marine invertebrates in general are known to detect the presence and spawning activity of conspecifics by sensing dissolved chemicals.

• Communication Channels
• chemical chemical

• Perception Channels
• chemical chemical

Food Habits

Pinctada margaritifera is a nonselective filter feeder that feeds mainly on plankton. It is found in oligotrophic coral reef atolls, where there is a low amount of productivity. Studies have found mud, inorganic materials, and other less than ideal items within its digestive tract.

• Primary Diet
• planktivore planktivore

• Animal Foods
• zooplankton zooplankton

• Plant Foods
• phytoplankton phytoplankton

• Foraging Behavior
• filter-feeding filter-feeding

Predation

Despite the protection of their calcareous valves, P. margaritifera is especially vulnerable to predation by sharks and rays. Other predators include octopus, starfish and predatory gastropods. In particular, the gastropod Chicoreus virgineus is described as the most dangerous predator for unprotected P. margaritifera within the Red Sea. Mud worms were responsible for the majority of P. margaritifera deaths in Palau. Pearl oysters are most vulnerable as larvae, because they are eaten by planktivores and are easily swept away from desirable benthic areas by ocean currents.

Ecosystem Roles

Bivalves are important in influencing phytoplankton concentrations through “top-down” grazer control. This action reduces particle density within the water and increases the amount of light which can reach benthic organisms. Bivalve waste can be assimilated as food for phytoplankton growth. Furthermore, the oyster beds form a sheltering hard-substrate habitat, housing numerous epifaunal and infaunal invertebrate species, and the oysters themselves are food for higher-order carnivores. Several types of Sporozoa are common parasites associated with Pinctada margaritifera and responsible for a large number of mollusk deaths. A number of parasitic annelid worms of the genus Polydora have had a similar effect on oyster mortality in the Persian Gulf.

Economic Importance for Humans: Positive

Pinctada margaritifera has been cultivated into a major commercial species for the pearl industry. Tahitian black pearls, derived from P. margaritifera and from Pinctada maxima account for about half of the world market. The pearl industry earned $18 million in exports for the Cook Islands in 2000. However, these numbers have substantially decreased due to a decrease in international pearl prices and problem with disease in Manihiki. In 2002, revenue fell to less than $11 million which includes profit from other forms of jewelry. Oysters of the genus Pinctada are not typically harvested for food, as other oyster species are.

• Positive Impacts
• body parts are source of valuable material

Economic Importance for Humans: Negative

There are no known adverse effects of P. margaritifera on humans.

Conservation Status

Pearls produced by P. margaritifera are valuable export items in the economies of Indo-pacific island nations. Because it is an important mariculture species, its farming locations are subject to environmental management to prevent negative human impacts on the oyster’s growth and health. Pinctada margaritifera has no special conservation status.

Additional Links

Encyclopedia of Life

Contributors

Albert Gamez (author), San Diego Mesa College, Paul Detwiler (editor), San Diego Mesa College, Angela Miner (editor), Animal Diversity Web Staff.

References

Bondad-Reantaso, M., S. McGladdery, F. Berthe. 2007. Pearl Oyster Health Management: A Manual . Rome: Food and Agriculture Organization of the United Nations. Accessed February 19, 2013 at http://books.google.com/books?hl=en&lr=&id=VODRzSd7QJYC&oi=fnd&pg=PA3&dq=Pinctada+margaritifera+habitat&ots=JN94HJ_O_s&sig=nIriER2c54aCFe6PjQBZrM5UtFU#v=onepage&q=Pinctada%20margaritifera%20habitat&f=false .

Chagot, D., A. Fourgerouse, M. Weppe, A. Marques, G. Bouix. 1993. A Gregarine ( Protozoa Sporozoa ) parasite of black-lipped pearl oysters Pinctada margaritifera (L., 1758) ( Mollusca Bivalvia ) from French Polynesia. Zoologie/Zoology (Parasitologie animale/Animal Parasitology) , 3: 239-244.

Doroudi, M., P. Southgate. 2003. Embryonic and Larval Development of Pinctada margaritifera (Linnaeus, 1758). Molluscan Research , 23.2: 101-107. Accessed February 19, 2013 at http://www.publish.csiro.au/?act=view_file&file_id=MR02015.pdf .

Keenan, E., R. Brainard, L. Basch. 2006. Historical and Present Status of the Pearl Oyster, Pinctada margaritfera , at Pearl and Hermes Atoll, Northwester Hawaiian Islands. Atoll Research Bulletin , 543: 333-344. Accessed February 19, 2013 at http://www.denix.osd.mil/nr/crid/Coral_Reef_Iniative_Database/NW_Hawaiian_Islands_files/Keenan%20et%20al.,%202006.pdf .

Le Moullac, G., B. Hui, V. Vonau, P. Levy, . Cochard. 2009. "Effect of Food Conditioning on Gonadic Activity in the Oyster Pinctada margaritifera " (On-line pdf). Accessed February 19, 2013 at http://archimer.ifremer.fr/doc/00029/14010/11196.pdf .

Loret, P., S. Le Gall, C. Dupuy, J. Blanchot, A. Pastoureaud, B. Delesalle, X. Caisey, G. Jonquières. 2000. Heterotrophic Protists as a Trophic Link between Picocyanobacteria and the Pearl Oyster Pinctada margaritifera in the Takapoto Lagoon (Tuamotu Archipelago, French Polynesia). Aquatic Microbial Ecology , 22: 215–226. Accessed February 19, 2013 at http://archimer.ifremer.fr/doc/2000/publication-823.pdf .

Loretuno, P., A. astoureaud, C. Bacher, B. Delesallel. 2000. Phytoplankton Composition and Selective Feeding of the Pearl Oyster Pinctada margaritifera in the Takapoto lagoon (Tuamotu Archipelago, French Polynesia): in Situ Study Using Optical Microscopy and HPLC Pigment Analysis. Marine Ecology Progress Series , 199: 55-67. Accessed February 19, 2013 at http://archimer.ifremer.fr/doc/00000/10992/7606.pdf .

McKenzie, E. 2004. "A COST-BENEFIT ANALYSIS OF PROJECTS IMPLEMENTED TO ASSIST THE BLACK PEARL INDUSTRY IN MANIHIKI LAGOON, COOK ISLANDS" (On-line pdf). Accessed May 14, 2013 at http://ict.sopac.org/VirLib/TR0371.pdf .

Mohammad, M. 1972. Infestation of the Pearl Oyster Pinctada margaritifera (Linné) by a new species of Polydora in Kuwait, Arabian Gulf. Hydrobiologia , 39: 463-477.

Newell, R. 2004. Ecosystem influences of natural and cultivated populations of suspension-feeding bivalve molluscs: a review. Journal of Shellfish Research , 23: 51.

Pagès, J., V. Prasil. 2000. "Effect of Water Confinement Upon Pearl-Oyster Growth Rate: Food Quality vs Quantity" (On-line pdf). Accessed February 19, 2013 at http://www.coremap.or.id/downloads/icrs9th-pages.pdf .

Sims, N. 1993. Pearl Oyster . Honiara Solomon Islands: Pacific Islands Forum Fisheries Agency. Accessed February 19, 2013 at http://www.spc.int/DigitalLibrary/Doc/FAME/FFA/Reports/FFA_1992_063.pdf .

Thielley, M., M. Weppe, C. Herbsut. 1993. Ultrastructural study of gametogenesis in the French Polynesian black pearl oyster Pinctada margaritifera ( Mollusca , Bivalvia ). I-Spermatogenesis. Journal of Shellfish Research , 12: 41.

Van Dyke, M. 2011. "Great Barrier Reef Invertebrates" (On-line). Accessed April 03, 2013 at http://www.gbri.org.au/Species/Pinctadamargaritifera.aspx?PageContentID=2402 .

Yukihira, H., D. Klumpp, J. Lucas. 1998. Effects of Body Size on Suspension Feeding and Energy Budgets of the Pearl Oysters Pinctada margaritifera and P. maxima . Marine Ecology Progress Series , 170: 119-130. Accessed February 19, 2013 at http://www.int-res.com/articles/meps/170/m170p119.pdf .

Yukihira, H., D. Klumpp, J. Lucas. 1999. Feeding Adaptations of the Pearl Oysters Pinctada margaritifera and P. maxima to Variations in Natural Particulates. Marine Ecology Progress Series , 182: 163-173. Accessed February 19, 2013 at http://www.int-res.com/articles/meps/182/m182p161.pdf .