Featured Research

from universities, journals, and other organizations

Pearl culture, the black gold of French Polynesia?

Date:
February 1, 2013
Source:
Institut de Recherche pour le Développement (IRD)
Summary:
The second greatest economic resource of French Polynesia after tourism, black pearl culture has been facing a major crisis since the first decade of this century. Overproduction, falling prices, reduced activity that had boosted many remote atolls.

Tahitian pearls
Credit: © IRD / B. Bourgeois.

The second greatest economic resource of French Polynesia after tourism, black pearl culture has been facing a major crisis since the first decade of this century. Overproduction, falling prices, reduced activity that had boosted many remote atolls... In response, IRD researchers and their partners(1) are helping to maintain and sustain the sector. In particular, scientists have been studying the Ahe atoll lagoon (north of Tahiti) since 2008. Specifically, they coordinated studies on the plankton resources available to feed oysters and on water flow in the lagoon.

Related Articles


These projects contribute to decision-making tools intended for oyster farmers, for the sustainable exploitation of the "Tahitian treasure."

Black pearl culture is currently the second greatest economic activity in French Polynesia after tourism. However, the young industry (2) experienced a major crisis at the beginning of the 2000s. The pearl price per gram fell from 100 to below 5 US dollars in 25 years. Overproduction and disorganised trade circuits are responsible. Pearl culture is currently going through a recovery phase and trying to restore the balance between supply and demand. At once completely dependent on the "lagoon" ecosystem and with a strong impact on this ecosystem, pearl farms must face multiple constraints.

Sustaining the sector

What are the best operating conditions to optimise production capacity and quality? Pearl size and quality are related to the attention given by producers to the culture cycle, but the farming environment remains decisive. In order to define the ideal conditions according to the lagoon environment, IRD researchers and their partners(1) have been conducting an extensive research programme since 2008, regarding the Ahe atoll located 500 km north-east of Tahiti. The Ahe lagoon covers 145 km² and accounted for nearly 80 pearl concessions in May 2012.

The Ahe lagoon and pearl culture

In order to assess the food resources available for pearl oysters in the South Pacific, called Pinctada margaritifera, researchers studied the spatial-temporal variations of the lagoon's planktonic communities over a year and their use by oysters. Result: molluscs retain more than 1% of the lagoon's primary production, i.e. organic plant matter. In fact, 80% of the latter is composed of very small (less than 2 micrometres) organisms which are badly assimilated by oysters. Furthermore, the planktonic trophic network has been characterised, thanks to techniques used for the first time in an atoll environment and the project's numerous partners. Lastly, the study and modelling of water flow have enabled an understanding of how environmental conditions influence the dispersion of oyster larvae, and thus why particular areas of the lagoon are more favourable than others to the collection of spats, juvenile oysters.

Low chemical pollution

The ecological impact of the pearl industry remains relatively unknown. Thousands of oysters have been artificially introduced into several lagoons. Sponges, anemones and other invasive epibionts, in other words living on other organisms such as oysters, were imported at the same time, increasing the health risk. Human populations around the farms can also pollute the lagoon. However, the work conducted by researchers on the Ahe atoll did not reveal any direct signs of chemical contamination of the environment or of eutrophication, i.e. the growth of algae due to an over-supply of nutrients(3) which depletes the water of oxygen.

The work on the Ahe toll enables a better understanding of the lagoon environment in relation to the pearl farming business, which should enable, in the medium term, to improve the technical and economic performances of pearl farming in Polynesia.

Notes :

  1. This work was carried out in partnership with the Division of Marine Resources in French Polynesia, Ifremer, CNRS and the universities of French Polynesia, Lille 1, Caen, La Rochelle and Aix-Marseille.
  2. Compared to the over-a-century-old white and golden pearl industry in Asia and Australia, black pearl culture, developed only in the 1960s, is relatively new.
  3. It contains mainly phosphorus and nitrogen from human activities.
  4. Polynesia has 250,000 inhabitants.

Did you know?

From the age of 2 to 3 years, pearl oysters are seeded with a small ball of nacre from a freshwater bivalve shell, the "nucleus," and a piece of mantle tissue taken from an oyster, the "graft." Over 18 months, a pearl will form and grow around the nucleus from the nacre of the graft.


Story Source:

The above story is based on materials provided by Institut de Recherche pour le Développement (IRD). Note: Materials may be edited for content and length.


Cite This Page:

Institut de Recherche pour le Développement (IRD). "Pearl culture, the black gold of French Polynesia?." ScienceDaily. ScienceDaily, 1 February 2013. <www.sciencedaily.com/releases/2013/02/130201114117.htm>.
Institut de Recherche pour le Développement (IRD). (2013, February 1). Pearl culture, the black gold of French Polynesia?. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2013/02/130201114117.htm
Institut de Recherche pour le Développement (IRD). "Pearl culture, the black gold of French Polynesia?." ScienceDaily. www.sciencedaily.com/releases/2013/02/130201114117.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Kids Die While Under Protective Services

Kids Die While Under Protective Services

AP (Dec. 18, 2014) — As part of a six-month investigation of child maltreatment deaths, the AP found that hundreds of deaths from horrific abuse and neglect could have been prevented. AP's Haven Daley reports. (Dec. 18) Video provided by AP
Powered by NewsLook.com
When You Lose Weight, This Is Where The Fat Goes

When You Lose Weight, This Is Where The Fat Goes

Newsy (Dec. 17, 2014) — Can fat disappear into thin air? New research finds that during weight loss, over 80 percent of a person's fat molecules escape through the lungs. Video provided by Newsy
Powered by NewsLook.com
The Hottest Food Trends for 2015

The Hottest Food Trends for 2015

Buzz60 (Dec. 17, 2014) — Urbanspoon predicts whicg food trends will dominate the culinary scene in 2015. Mara Montalbano (@maramontalbano) has the story. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins