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The mystery of pearls in the Ria Formosa

by EMMA BERTENSHAW [email protected]

University of the Algarve (UALG) has long been gaining a reputation of excellence based on the research of the local natural environment with emphasis on marine biology and the impact of man in the Algarve coastal environment.

The Centro de Ciências do Mar do Algarve (CCMAR) – Centre of Marine Sciences in the Algarve (www.ccmar.ualg.pt) – is a non-profit scientific research centre set up to provide facilities for training and on-site research alongside the University.

Linked to a similar centre (CIMAR- Centre of Marine and Environmental Investigation) at the University of Porto, it is considered to be an important international research base.

With an unrivalled location close to the Ria Formosa natural park, scientists and graduate students from UALG are able to study the unique conditions of the Iberian habitat.

One of the pearls discovered in Algarve-grown oysters. Photo: SUPPLIED
One of the pearls discovered in Algarve-grown oysters. Photo: SUPPLIED

Deborah Power is a British professor of Biotechnology at UALG and has been based in the Algarve for over 22 years. Her department is one of the leading faculties in the University and links to other important institutions around the world studying Endocrinology, Biotechnology and Aquaculture.

Recently, the discovery of pearls in oysters of the Algarve region was a surprise to her and the team of scientists (including Dr Fred Batista) from CCMAR, who discovered them, as it is considered to be a relatively rare occurrence for Europe.

Killer virus

Deborah Power explained that a team of research scientists were conducting a study of the oysters along the Algarve coast in response to reports of a virus that had been killing off the oyster production.

In the early 1970s, Portuguese oysters, farmed in large quantities for export, were attacked by a virus that killed off a major percentage of this lucrative trade.

A new Pacific oyster was then introduced to replace the native species which resisted the disease. Native oysters survived but only in depleted numbers.

Recently however, the reverse happened when it became the Pacific oysters’ turn to suffer a disease.

The native and Pacific oysters are also able to produce a hybrid variety and the studies hope to reveal which oyster actually produced the pearls as there is very little visual difference between them.

“We discovered four oysters with pearls in them. One pearl was a lot larger (5mm diameter) than the others and led us to consider further studies of this rare phenomenon,” Deborah told the Algarve Resident.

The pearls, which are honey-pink coloured, have been sent to Cambridge University where their molecular structure is being scrutinised by further tests.

Deborah hopes there may be clues in the structure of the pearls. “It would be interesting to know why the pearls formed as we don’t know whether it is the result of a foreign substance invading the oyster’s shell or due to certain changes in the environmental conditions where they were growing,” she said.

This knowledge could have environmental impact on the region or could affect fishing. It could alternatively provide useful information for medical science in the development of resistance to disease as the scientists study the organisms’ reactions to change.

“These biomaterials are carbon-based like us humans. The knowledge we gain can be developed into endless uses for medicine or technology,” said Deborah.

Pearl business

Commercial production of pearls is dominated by China (producing 96% of pearls sold worldwide as jewellery) as they have been for many years in the far-east. Very few pearls of gem quality sold are natural and ‘cultured pearls’ are farmed to conform to a standard size and appearance. It is unlikely that the find would lead to growing the pearls for sale.

Oyster production in the Algarve is exported to France. French producers typically provide the ‘spat’ (oyster spawn) in their own hatcheries which is then sold to Portuguese producers who grow them in the warmer waters of the Algarve.

When asked why the Algarve could not also have its own hatcheries, Deborah pointed out. “Production for fisheries is incredibly demanding requiring a high level of care and investment to achieve a high yield.”

Regulation of temperature, densities and water quality are part of the high labour requirements to produce large quantities for export.

When they are fully grown, the oysters are sold back to the French, who then prepare them for market.

Although it is an expensive product, it is currently only incubated in the Algarve, where they do not retain much of the profit, and they are not frequently on the menu here in an area where they grow naturally.

It has been reported that the French oyster industry is worth around €400 million a year to the European market as both producers and consumers. With supply dwindling due to virus problems, the price is going up but the market constricting.

Overall European production of oysters has been reported to be in the region of 126,000 tonnes a year but producing regions have all been affected by the virus which spreads rapidly.

Deborah quoted that 800 tonnes were produced by Portugal alone in 2009, which explains why this research by the local university could be of great importance to Algarve commerce both now and in the future.

As for now, the answers to the problem virus lie in further research by centres such as those currently at UALG.

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