Natural pearl found in an oyster Crassostrea. (Photo: CCMAR)
Pearls found in oyster farming
Tuesday, January 17, 2012, 02:50 (GMT + 9)
A team of researchers at the Research Institute for Agriculture and Fisheries (IPIMAR) and the Centre of Marine Sciences, University of Algarve (CCMAR), found pearls in oysters of Crassostrea family growing in several areas of Algarve.
IPIMAR’s scientists Frederico Batista and Ana Grade, and Deborah Power of CCMAR, clarified that this finding is incredibly rare and that they had never seen anything like it in their 10 years of observation and study of the species.
Two out of 756 oysters harvested in different places in Algarve, which included Alvor estuary, Ria Formosa and river Guadinana, contained pearls.
According to experts, one of the oysters contained four pearls that were less than 2 millimetres in diameter and the other was a single pearl oyster 5 mm in diameter and weighing 190 mg.
It is common to find pearls in oysters of the Pteriidae family, but not in Crassotrea, the scientists said.
Pearls are produced by bivalves as a defence reaction in the presence of foreign bodies such as parasites.
The invading particle is covered by layers of a substance made primarily of calcium carbonate in the form of aragonite crystals.
The investigators continue to conduct additional studies to better understand the phenomenon and find out what factors lead to the development of pearls, Expresso reported.
"We do not know very well what it was that developed the phenomenon, but we want to explain that there is nothing wrong and that is due to the characteristics of the environment", said Batista.
"Oysters may be of the species Crassostrea angulata (Portuguese oyster), Crassostrea gigas (Pacific oyster) or hybrid", he added.
He continued, "what is valuable is its rarity", not its brightness or colour, Ciencia Hoy reported.
The pearls found by the group of scientists were sent to a laboratory in Cambridge for analysis.
By Analia Murias