Reproductive cycle of olivancillaria vesica auricularia (LAMARCK, 1810) (MOLLUSCA: GASTROPODA: OLIVIDAE) in Southern Brazil

Abstract

The reproductive cycle of livancillaria vesica auricularia on Cassino Beach, Rio Grande, RS was analyzed to determine the stages of gonad maturation according to the presence of germinate cells, correlating them to the environmental factors. Between December, 1996 and June, 1998 ten adults of each sex were collected monthly. The gonad showed five stages: “partially ripe”; ripe”, “partially spawned”, “spawned” and, only in males, “restinging”. The temperature variations have significant influence on the reproductive cycle of Olivancillaria vesica auricularia. Gonadal maturation was observed from September 1997 to December 1997, followed by the spawn from January 1997 to April/1997 and from December 1997 to March 1998. The resting period was recorded during fall and winter. During this study, the reproductive cycle has suffered the influence of environmental changes due to the severe storms occurred on January and March 1998, which suspended and transported fluid mud to the beach.