A description of the larval development of Megabalanus azoricus (Pilsbry, 1916) reared in the laboratory

Abstract

This study provides the first description of the larval development of the commercially exploited barnacle Megabalanus azoricus. It describes the changes in larval size and shape as well as the general morphology and duration of each larval stage. Embryos were obtained from gravid specimens collected at São Miguel Island and reared through six naupliar stages to the cypris stage in laboratory conditions. The planktotrophic nauplii reached the cypris stage after 14 days of hatching in individual cultures at 20 °C under natural illumination and fed with phytoplankton (Chaetoceros gracilis, Isochrysis sp., and Tetraselmis sp.). The nauplius of M. azoricus has a normal size compared with nauplii of other congeneric species, ranging between the 261 μm (nauplius I) and 912 μm (nauplius VI). This work provides the first description of larvae of the genus Megabalanus for the Portuguese oceanic islands and provides comparisons with congeneric species in other parts of the world.