Advances in oyster farming have been achieved with biotechnological applications, such as chromosome manipulations aimed at polyploidy. The bivalve Anomalocardia brasiliana is of considerable importance to artisanal fishing activities and is a potential organism for aquaculture in Brazil. The cytogenetic behavior of polar bodies during meiosis provides essential information for chromosome manipulation directed at the production of triploid organisms. The objective of the present study was to identify postfertilization times in which the polar bodies are expelled and determine the most frequent number of chromosomes in A. brasiliana. Individuals were caught on the coast of the state of Pernambuco, in northeast Brazil, and subsequently induced to release the gametes. Samples of the oocyte solution were taken before and every 2 min after fertilization. The material was fixed in Carnoy's solution, stained with 4′,6-diamidino-2-phenylindole and photographed under an epifluorescence microscope. Among the 50 oocytes analyzed in metaphase I, 19 bivalents were found. The release of the first polar body was detected 10 min after fertilization among 70% of the eggs, whereas the second polar body was released at 16 min among 62% of the eggs. This work provides relevant information on the time of initiation of shock treatments for chromosome set manipulation, aiming triploids of this important marine fishery resource in Brazil.