Embryonic development and reproductive seasonality of Buccinanops globulosus (Nassariidae) (Kiener, 1834) in Patagonia, Argentina

Abstract

Buccinanops globulosus mated all year round, with higher frequency from May to September, prior to spawning months. Gravid females were found between October and March. Oviposition peaked during rising temperatures and longest daylength while hatching peaked with high water temperature and declining daylength. Gravid females measured between 20 and 41 mm in shell length. The spawn consisted on average of 31 egg capsules, each containing 1266 eggs. Embryos usually completed development within each egg capsule by ingesting small fragments of the uncleaved nurse eggs, which were not a limiting resource. Egg capsules with more than one embryo were not common; in those cases, the embryos had different sizes probably related to intracapsular competition for nutrients, and were on average smaller than solitary embryos in the other capsules. Embryos hatched as crawling juveniles with a mean hatchling shell length of ~3.4 mm. In a few cases, malformed embryos were found, but it was not a common phenomenon. The information recorded in this study, as the minimum reproductive size and spawning season, is valuable for fisheries management.