Notes on pearls produced by Anomalocardia brasiliana (Bivalvia, Veneridae) (GMELIN, 1791) in a estuary of Ceará

Abstract

The species Anomalocardia brasiliana (Gmelin, 1791), belonging to the Veneridae family has a wide geographic distribution and can be found all along the Brazilian coast. They are filtering organisms, dioecious of external fertilization and are adapted to a great variety of habitats. The present study records the occurrence of pearls in veneridae of the species A. brasiliana collected in an area of the Acaraú River estuary, near the beach of Volta do Rio. The collections were carried out monthly from January / 2015 to December / 2015, in the periods of low tide. For which the random squares method was used, where it randomly plays a square of PVC of 50cm x 50cm and digs the sediment from within the same aid of spoons to a depth of 5 cm. A total of 9152 animals were collected and examined, their shell length ranged from 2.67 mm to 33.21 mm. Six small pearls of spheroid shape were extracted from the total analyzed, showing low incidence in relation to the total sampled. The knowledge of pearls A. brasiliana in northeastern Brazil stimulates further studies to elucidate this pearl production, particularly on environmental variables effects in this process.