2011 Volume 28 Issue 2 Pages 47-54
We examined the settlement response and mortality of cyprids of four barnacle species, Megabalanus rosa, Chelonibia testudinaria, Amphibalanus amphitrite, and Balanus trigonus, exposed to various salinities. Cultured nauplius larvae of each species were fed on Chaetoceros gracilis until they reached the cypris stage. Settlement assays were carried out using airtight Petri dishes filled with test seawater includ- ing cyprids under the dark condition at 20°C ± 2°C. The salinity was adjusted from 10 to 50 psu using fil- tered (0.22 μm) natural seawater and distilled water. Cyprids of A. amphitrite settled and metamorphosed in the entire range of salinity examined, with low mortalitiy. On the other hand, metamorphosis of M. rosa and B. trigonus was observed only from 26 to 46 psu, and larvae of both species died at 10 and 14 psu. Settlement of C. testudinaria was observed from 18 to 34 psu, with almost 50% cyprid mortality at 10 psu. These results seem to reflect the natural distribution of these barnacle species.
