Black Pearl Aquaculture in French Polynesia

Please also see the Black Pearl Aquaculture Photo Journal that accompanies this entry.

History and Process
Aquaculturists in French Polynesia have farmed a variety of organisms, with none being more successful than the black pearl oyster. In the early 1960s the French Polynesian people started to develop practices of black pearl aquaculture, their most lucrative venture to date.[1] Most pearl aquaculture takes place in the Tuamotu and Gambier Archipelagos, employing about 4,000 to 7,000 people.[2] In the 1990s, there was a boom in pearl oyster aquaculture; now French Polynesian farms account for 90% of black pearl production in the world.[3]

The black-lipped pearl oysters famous in French Polynesia are marine oysters, Pinctada margaritifera. These bivalves were naturally abundant in the benthic waters of French Polynesian lagoons,[4] but now are cultivated in deeper pelagic environments on long suspended lines.[5] Wild oysters make pearls when a sand grain or other foreign particle enters their body cavity. They cover the irritant with layers of shiny nacre, a substance which is mostly calcium carbonate, organic material, and water.[6] In the 1900s, Japanese scientist Kichimatsu Mikimoto found a way to insert a nucleus into an oyster and produce a pearl artificially.[7] This process allowed for the production of flawless round pearls of great market value.[8]

Oysters are natural filter feeders that live on the ocean bottom and trap plant and animal particles with their gills. They spawn twice each year, in November and March, and their juvenile stage is called spat. Pearl oysters used in aquaculture are selected from wild spat, implanted onto lines, rafts, or underwater trestles, and allowed to grow for several years[9]. Next, pearl technicians surgically graft oysters to produce pearls.[10] During this process, part of another oyster’s mantle, a muscle that is responsible for shell growth, is cut away and inserted into a sac near the pearl-producing oyster’s gonad.[11] The mantle of one sacrificial oyster that produced nacre of a desirable quality and color is often divided into up to 30 pieces, so one oyster’s mantle is used for about 30 pearls. The technician also inserts a nucleus, carved to be perfectly round from an external substance, usually the shell of an American mussel. These mussels have shells that are thick enough to create a large bead, and their texture is similar to that of the pearl and ideal for drilling. The nuclei are shipped from the United States to China, where they are shaped and dyed yellow with antiseptic, and then are sent to French Polynesia.[12] The pearl oyster can secrete nacre around the nucleus at a rate of about 7.1 micrometers a day for the first year, but this rate decreases dramatically every year.[13]

Environmental Considerations
Rising sea surface temperatures and the resulting chemical effects of global warming, such as a reduction in dissolved oxygen in ocean waters, have noticeable effects on pearl aquaculture production. Warmer waters in lagoons decrease the pearl’s luster and therefore the pearl’s value, as nacre deposition upon the pearls is of poorer quality in warmer waters.[14] Oysters prefer relatively clear, fast moving water and stable cool temperatures for maximum nacre deposition.[15] Already, some island archipelagos where water is historically warmer are producing lower-quality pearls, as water temperatures rise even higher.[16]

Furthermore, warmer seawater can hold less dissolved oxygen, forcing competition among lagoon organisms for oxygen to breathe. Parasites that can grow favorably in warm water use a significant amount of oxygen; their growth can inhibit the formation of high-quality pearls, as the oysters must struggle to stay alive. However, this problem can be mitigated by farmers carefully scrubbing the oysters more frequently to remove pests. This solution was successfully implemented in the past when a bloom of anemones “suffocated” the oysters, but they were removed by more frequent cleanings[17].

As farmers work to protect their pearl harvests from environmental stressors, ecosystems must similarly stabilize the inputs and outputs of pearl oysters concentrated on farms. By understanding the environmental consequences of the industry, it is possible to maintain a balance between ecologic conservation and economic interest, allowing for effective resource management. There are several moderate environmental impacts to the important lagoon ecosystems hosting the farms.[18]

Because of the dense nature of pearl oyster farming in French Polynesia, the most frequently reported ecological impact is increased sedimentation from the production of fecal matter.[19] As oysters hang on lines, all of their waste accumulates below, causing a buildup of sediments at a faster than normal rate, impacting infaunal organisms.[20] Another threat to native ecosystems is the accidental introduction of exotic organisms through spat collection from locations outside the farm area.[21] Endemic species are also threatened by entanglement in the large amount of netting used to host the oysters during growth.[22]

Pearl aquaculture also has effects on the oysters themselves, mostly through the spread of disease. By clustering a large number of oysters in a small space, naturally occurring bacteria are able to multiply, causing disease outbreaks.[23] One particular epidemic of the bacterium Vibrio harveyi in the 1970s and 1980s caused significant oyster mortality, which lead to improvement in handling techniques and lessening of oyster density on the farm.[24] However, workers in the pearl industry take pride in the strong research efforts in disease prevention occurring since the 1980s.[25] Some studies have indicated that the pearl industry could positively impact the water quality of a local area. Researchers find that the filtering capacity of pearl oysters leads to bioaccumulation of pollutants like heavy metals, pesticides, and hydrocarbons.[26] Farming and coastal urbanization in French Polynesia have caused increased seawater nutrient levels, driving changes in near-shore and lagoon ecosystems.[27] These resultant water quality changes could be reversed through introduction of pearl farms, providing profit and sustainable lagoon cleaning.

The pearl aquaculture industry in French Polynesia is regionally relevant because of its economic importance and significant environmental impacts. The environmental impacts of pearl oyster aquaculture in French Polynesia are both positive and negative, and a balance is needed for this practice to be sustainable. The water filtering qualities of these bivalve organisms can be utilized to clean up coastal waters, but high-density commercial farms can negatively impact local ecosystems through spread of disease and waste produced as a result of fouling removal. Policy regulating these farms is necessary in order to ensure that the positive effects of the industry outweigh the negative impacts.[28]

Policy and Industry Regulations
In French Polynesia, aquaculture is the second highest producer of income after tourism[29]. There are few employment opportunities for many Pacific islanders, and aquaculture provides many jobs.[30] Aquaculture can also help provide fresh food for local populations, and the products can also be exported to other countries, a pathway which opens trade connections and produces revenue for French Polynesia. The black pearl industry began in the 1960s and became successful in the 1980s.[31] At that time there was little management and regulation, but there is now a growing need to build administrative systems to manage problems in the industry.[32] The regulations surrounding the pearl farming industry are complicated and dynamic. People in the industry consider the frequent shifts in regulations problematic and think that fixed rules must be set in order for the industry and market to grow.[33] Government guidelines fall into two categories: those addressing pearl quality and farm operations.

Pearl quality is very strictly regulated in French Polynesia. Pearls are harvested at the farms and sent to Pape’ete, Tahiti for control.[34] This control process has many steps to provide the consumer with a quality product. The pearls are x-rayed to see that they reach the 0.8 mm thickness minimum. This thickness refers to the layer of nacre around the nucleus of the pearl. If the pearl does not meet this standard it cannot be sold.[35] The pearls are also visually checked for spots or imperfections. A perfect pearl would receive an A rating, and there is a scale through to a D rating for the least desirable, but still quality pearl.[36] To achieve an A rating, the pearl surface has little imperfection, a B rating can have small imperfections visible, C means that less than 2/3 of the surface has imperfections, and D has relatively visible imperfections on the surface. These lower quality D pearls usually have a design carved into the surface to hide the imperfections in a creative way.[37] On average about 3% of pearls are rejected and subsequently destroyed if they do not meet the standards.[38] Other sorting regulations include the color, size, shape, and luster of the pearl.[39] There is a magnificent array of colors that a Tahitian pearl can take, from the traditional dark grey or black to shades of blue and pink.[40] There is also research into techniques to control the color of the resulting pearl, which cannot currently be dictated naturally.[41] Most pearls produced by farming techniques range in size from nine to twelve millimeters.[42] The available pearl shapes vary depending on the oyster’s environment and the oyster itself.[43] Shape categories include round/ semi-round, oval/ button, drop, circle, and semi-baroque/baroque.[44]

Farm regulations are not as stringent as pearl quality regulations, as pearl farms are often remote from each other and local centers of government. The aquaculture industry is observed and regulated by the state (French Polynesia), territories (such as Windward Islands or Marquesas Islands), and the communes (such as Faa’a or Pape’ete in Tahiti) within French Polynesia. The farmers are regulated by concessions for harvesting and farming. Permits are required and taxing is customary for exporting any goods.[45]

The farmers on the more easily accessible atolls, such as Rangiroa, have yearly visits by boat from the government to check for problems with grafter registration and location parameters among other restrictions.[46] It is very difficult to actually check the oysters because that requires the officers or other officials to dive.[47] The local police force also keeps control of the boats, engines, and scuba diving that are in regular use on a pearl farm. Many atolls with farms are located outside the easily accessible areas for the government. These atolls may find it profitable and possible to hire employees and not register the workers. They also could under-report the amount of land/ocean they are using for farming and not have to pay the full amount of taxes due.[48] These types of manipulations are one area of regulation that is in need of remodeling, and is a common complaint within the pearl regulation community,[49] because it greatly affects the pearl market. The farms without regulation can save money in the production process and sell their pearls for less money while still making a profit. This means they are selling at a lower rate than other farms and driving the value of the pearl down.[50]

Another important factor for formation of regulations on pearl farms is water quality. There are no direct regulations with regard to nutrients and pollutants in the water, which has caused problems for the market in the past.[51] Just a few years ago there were many more farmers in French Polynesia, polluting the lagoons. There were not enough nutrients for the pearls and so the quality was affected as well as the market, with many farms closing.[52] In 2008 there were around 1,000 farms in French Polynesia and now there are about 200 remaining.[53] Cleaning the oysters is another area of concern for the government and farms alike. Oysters that are not regularly cleaned can be suffocated by anemones and other organisms that grow on the shells.[54] While cleaning the oysters is beneficial to pearl production it has caused difficulties in the past. As the anemones were cleaned off the oyster shells they multiplied in the surrounding areas. The government responded by placing regulations on farms to collect the removed materials in a container instead of dumping into the open ocean.[55] As with similar farm regulations, it is difficult to enforce such procedures when government officials inspect farms once a year maximum and do not dive down to see the oysters.[56]

The distinctly different approaches to pearl aquaculture in Australia and French Polynesia provide great insight to the lack of regulation of Tahitian black pearls. Australia has many restrictions and few licenses are given for the industry. It is straightforward in Australia that without these intense regulations the industry would die from depleted stock.[57] Most companies in Australia are very large operators because expensive equipment is needed to collect spat from the open ocean.[58] Since Australian industry is much more expensive and they have restricted quotas, an emphasis is put on producing the best quality pearls because they cannot be produced in large volumes. In French Polynesia the story is very different. There are mostly small-scale operations since they are relatively easy to set up; in French Polynesia there is a relatively simpler process to get concession and start a business.[59] Sometimes the lack of regulation allows for business owners to get away with not paying fees or even going unregistered.[60] There are no quotas on grafting the oysters, so the pearls are now over-produced and prices are declining.[61] Regulations will become persistently more and more significant to the industry as climate changes affect the pearl farming environment. Warming water will affect the pearl luster and as such deteriorations in quality occurs research and regulations must adapt to the new challenges facing the industry.

Few suggestions have been made for readying pearl aquaculture facilities for the impacts of climate change. The Secretariat of the Pacific Community suggests mapping the current locations of all of the marine aquaculture facilities on the small atolls, and also diversifying the production of these small farms. They also suggest the relocation of pearl farms to unspecified deeper water locations in proximity to reefs and “algal areas,” where the saturation of aragonite in the water would be high enough due to a normal pH[62] and might be better for healthy pearl production. However, most of the aquaculture reform focuses on freshwater ponds, and not on the highly lucrative pearl industry.  More research into this area will hopefully occur as a result of worldwide demand for Tahitian pearls.

An increase in globalization has led to the transfer of goods across the borders of countries and around the world. The French Polynesian pearl aquaculture industry is no exception to the globalization trend. As demands for products increase, it becomes more and more important to implement healthy and sustainable practices for producing goods.[63] However, local and national fishing administrations are generally weak and underfunded, so regulation of aquaculture practices is limited. One researcher found that national fisheries agencies only spend a quarter of their resources regulating coastal areas, and that less than 40% of villages in the Pacific had been in communication with officials about coastal resource management within the last 10 years.[64] There have been many suggestions from outside countries as to what kind of environmental policy should be implemented in Pacific island nations, but actual creation and enforcement of policy is traditionally weak in these areas.[65] More and more of the responsibility for fisheries and environmental management is now being handled by local communities rather than trying to sustain a centralized policy structure.[66]

As with many ocean-based industries, climate change and seawater change will impact the success of pearl oyster aquaculture. Pacific island countries have some policies that prevent reef damage to mitigate sea level rise and limit farm runoff into oceans. Unfortunately, there are few local institutional resources that can help to develop policy about climate change; many Pacific nations are adapting policies developed in other regions of the world. Unregulated export of goods like fish and pearls leads to heightened conflict between a need to generate income in areas without other economic options and a need to sustain these resources for continued use.[67]

In French Polynesia, black pearl aquaculture regulation is centralized through Pape’ete. However, most of the island groups have unwritten but accepted farming and fishing practices that keep their own ecosystems healthy.[68] Clean environments are necessary not only to sustain life on the islands, but the ecosystems also provide ideal locations for pearl farms. Pearl growers emphasize local responsibility for ecosystem management through practices like spear fishing over net fishing.[69] Although the pearls themselves must pass regulations in Pape’ete, farming techniques and practices are still often locally regulated, which allows pearl farms to operate in different ecosystems while ensuring high quality of French Polynesian pearls.

Kate Enright, Wesleyan University
Jerelle Jesse, University of Massachusetts - Dartmouth
Hannah Wagner, Hamilton College
2014

References

[1]  Secretariat of the Pacific Community Aquaculture Portal (SPC). 2011. Commodities: pearl oyster. Web. 18 Feb. 2014. <http://www.spc.int/aquaculture/index.php?option=com_commodities&view=commodity&id=15>

[2]  Food and Agriculture Organization of the United Nations, Fisheries and Aquaculture Department. 2012. National Aquaculture Sector Overview: France. Web. Accessed 19 Feb 2014. <http://www.fao.org/fishery/countrysector/naso_france/en>

[3]  SPC Aquaculture Portal. 2011.

[4]  Jadhav, U. 2009. Aquaculture Technology and Environment. New Delhi: PHI Learning.

[5]  Pouvreau, S., C. Bacher and M. Heral. 2000. Ecophysiological model of growth and reproduction of the black pearl oyster, Pinctada margaritifera: potential applications for pearl farming in French Polynesia. Aquaculture. 186 (1-2):117-144.

[6]  Jadhav, 2009.

[7]  Anonymous sales representative. March 24, 2014. Robert WAN Tahiti. Papeete, Tahiti. Personal Interview.

[8]  Ellis, S. and M. Haws. 1999. Producing Pearls Using the Black-lip Pearl Oyster. Center for Tropical and Subtropical Aquaculture Publication.

[9]  Ellis, and Haws. 1999.

[10]  Ellis and Haws. 1999.

[11]  Wells, F. and P. Jernakoff. 2006. An assessment of the environmental impact of wild harvest pearl aquaculture (Pinctada maxima) in Western Australia. Journal of Shellfish Research. 25(1):141-150.

[12]  Ripa, Stephane. March 29, 2014. Gauguin’s Pearl Farm. Avatoru, Rangiroa. Personal Interview.

[13]  Pouvreau et al., 2000.

[14]  Secretariat of the Pacific Community. 2010. French Polynesia Aquaculture Presentation. Web. 22 Feb 2014. <http://www.spc.int/aquaculture/index.php?option=com_docman&task=doc_download&gid=313&Itemid=32/.>

[15]  Jadhav, 2009.

[16]  Moe, Elisabeth. March 24, 2014. Maison de la Perle. Papeete, Tahiti. Personal Interview.

[17]  Moe, 2014.

[18]  Wells and Jernakoff, 2006.

[19]  Gifford, S., H. Dunstan, W. O’Connor, T. Roberts and R. Toia. 2004. Pearl Aquaculture – Profitable Environmental Remediation? The Science of the Total Environment. 319:27 – 37.

[20]  Wells and Jernakoff, 2006.

[21]  Andrefouet, S. 2012. Recent Research for pearl oyster aquaculture management in French Polynesia. Marine Marine Pollution Bulletin 65(10-12):407-414.

[22]  Wells and Jernakoff, 2006.

[23]  Wells and Jernakoff, 2006.

[24]  Wells and Jernakoff, 2006.

[25]  Ripa, 2014.

[26]  Gifford et al., 2004.

[27]  Gifford et al., 2004.

[28]  Humbert, J. 2007. About Kamoka pearl. Web. Accessed 18 Feb 2014. <http://www.kamokapearls.com/english/about/index.html>

[29]  SPC Aquaculture Portal. 2011.

[30]  Cabral, P. 1989. Problem and perspectives of the pearl oyster aquaculture in French Polynesia. Advances in Tropical Aquaculture, Workshop at Tahiti, French Polynesia. 20 Feb-4 March 1989. Web. Accessed 22 Feb 2014. <http://archimer.ifremer.fr/doc/1989/acte-1494.pdf>

[31]  SPC Aquaculture Portal. 2011.

[32]  Rapaport, M. 1995. Oysterlust: islanders, entrepreneurs, and colonial policy over Tuamotu lagoons. Journal of Pacific History. 50 (1): 39-52.

[33]  Moe, 2014.

[34]  Moe, 2014.

[35]  Pascal, Mitchen. March 24, 2014. Maison de la Perle. Papeete, Tahiti. Personal Interview.

[36]  Ripa, 2014.

[37]  Ripa, 2014.

[38]  Ripa, 2014.

[39]  Anonymous sales representative, 2014.

[40]  Anonymous Sales Representative, 2014.

[41]  Moe, 2014.

[42]  Anonymous Sales Representative, 2014.

[43]  Ripa, 2014.

[44]  Ripa, 2014.

[45]  Evans, N., J. Raj and D. Williams. 2003. Review of aquaculture policy and legislation in the Pacific Island region. SPC Aquaculture Technical Papers. 168 pp.

[46]  Ripa, 2014.

[47]  Moe, 2014.

[48]  Ripa, 2014.

[49]  Ripa, 2014.

[50]  Ripa, 2014.

[51]  Moe, 2014.

[52]  Moe, 2014.

[53]  Ripa, 2014.

[54]  Moe, 2014.

[55]  Moe, 2014.

[56]  Ripa, 2014.

[57]  Poirine, B. and C. Tisdell. 2001. Socio-economics of Pearl Culture: Industry Changes and Comparisons Focusing on Australia and French Polynesia. Secretariat of the Pacific Community. World Aquaculture. Web. 22 Feb 2014. < http://www.spc.int/DigitalLibrary/Doc/FAME/InfoBull/POIB/14/POIB14_21_Tisdell.pdf>

[58]  Poirine and Tisdell, 2001.

[59]  Poirine and Tisdell, 2001.

[60]  Poirine and Tisdell, 2001.

[61]  Poirine and Tisdell, 2001.

[62]  Doney, S., V. Fabry, R. Feely and J. Kleypas. 2009. Ocean Acidification: The other CO2 problem. Annual Reviews of Marine Science. 1:169-192.

[63]  Andrefouet, 2012.

[64]  Hunt, C. 2003. Economic globalisation impacts on Pacific marine resources. Marine Policy. 27:75-85.

[65]  Hunt, 2003.

[66]  Hunt, 2003.

[67]  Hunt, 2003.

[68]  Ripa, 2014.

[69]  Ripa, 2014.

 

How to cite this entry:
Kate Enright, Jerelle Jesse and Hannah Wagner. 2014. “Black Pearl Aquaculture in French Polynesia.” Atlas for Sustainability in Polynesian Island Cultures and Ecosystems. Sea Education Association, Woods Hole, MA. Web. [Date accessed] <html>