Reproductive cycle and oviposition inZidona dufresnei(Caenogastropoda: Volutidae) from northern Patagonia, Argentina

Abstract

This study describes the reproductive cycle in the edible marine snail Zidona dufresnei in San Antonio Bay (Patagonia, Argentina), an unusual population that inhabits shallow waters. Histological techniques together with monthly field observations over a two-year period were used to describe the gametogenic cycle, the season of oviposition and the presence of egg capsules. Females were mature from August to April and there was proliferation of the germinal epithelium immediately after evacuation. Growth and resorption of oocytes were observed throughout the study period. Males were reproductively active throughout the year. The histological analysis is consistent with the observations in nature, in which females were recorded depositing egg capsules from late August to late April. The reproductive period seems to be closely related to water temperature and photoperiod. The relatively high seawater temperature in San Antonio Bay may be one of the relevant factors that contributes to the extended period of oviposition and gamete evacuation in Z. dufresnei.