Larval development of the Megabalanus coccopoma (Darwin, 1854) and temporal variation in Itapocoroy bay (Santa Catarina, Brazil)

Abstract

Eight species of barnacle are observed on the mollusk culture systems of Itapocoroy bay, northern coast of Santa Catarina, Brazil, where Megabalanus coccopoma, is the most abundant species. Rearing the larvae in the field zooplankton samples. In order to study the temporal variation of cirripedian larvae, weekly zooplankton samplings were done between april/95 and january/97. The sampling point was located inside the oyster and mussel culture area, where the continuous occurrence of Nauplii was observed along the sampled period, with peaks of abundance found during the end of spring and beginning of summer, following the increase in temperature. Five species of Cirripedia were identified in the plankton samples: Megabalanus coccopoma, Balanus amphitrite, Balanus improvisus, Balanus trigonus e Chelonibia patula. Nauplii of Megabalanus coccopoma was dominant in the samples, exhibiting a high percentage of stage II with suggests a continuous larval production in the environment. Variation in cirripedian larvae density during the 21 months sampled, suggests an increase in abundance that can be related to the increase of the adult population, favored by the increment in the available substract.