Reproductive cycle, larval distribution, settlement, and initial growth of the barnacle Balanus rostratus in Mutsu Bay, northern Japan

The barnacle Balanus rostratus (Cirripedia, Crustacea) has recently become recognized as a valuable edible crustacean. We aimed to determine its ecological properties for future cultivation. Histological and field surveys showed that this barnacle reproduces once from October to November. Gut contents and C/N ratio analyses revealed that adults mainly fed on phytoplankton and detritus and accumulated sufficient nutrition in the ovaries and its connective tissues until spring. Gonadogenesis continued and was completed in autumn. Field surveys showed that nauplii were released in December, and transported to and retained in the eastern half of Mutsu Bay. Cyprids settled on the test plates that were set from the surface to the bottom until March. Its larval period from December to March was within the time for exchange of water mass in Mutsu Bay and probably explains the high holding capacity of this species in this bay. Shell size reached 40-45 mm in basal diameter within two years, although growth slowed during summer.