Reproductive cycle of the mangrove oyster, <i>Crassostrea gasar</i> (Adanson, 1757), in tropical and temperate climates

Abstract

The reproductive cycle of Crassostrea gasar oysters from a single origin (Federal University of Santa Catarina hatchery) was studied by culturing the species for 1 year in four distinct areas of Brazil; two of which were in tropical climates (02°44′S, 41°58′W; 02°47′S, 41°55′W) and two in temperate climates (26°28′S, 48°50′W; 27°35′S, 48°32′W). In each area, 20 individuals were collected each month for reproductive cycle analysis using standard histological techniques. Oysters cultivated in tropical climates demonstrated intermittent reproductive cycles, with individuals spawning throughout the year and rarely entering a resting stage. Oysters cultivated in temperate climates demonstrated spawning periods associated with increases in water temperatures, occurring in late spring and summer. Resting stages were clearly seen in samples from latitudes of 26 and 27 °S, with approximately 75% to 100% of the individuals in this stage between May and July.