Brooding in the intertidal barnacles Chthamalus stellatus (Poli) and Chthalamus montagui Southward in south-western Ireland

At Lough Hyne Marine Nature Reserve, western Cork, Ireland, the intertidal barnacles Chthamalus stellatus (Poli) and Chthamalus montagui Southward were shown to be capable of breeding in their first year after settlement. In C. montagui, zero, one or two broods and in C. stellatus, zero, one, two or in a single case three broods were produced in the first summer. Whether or not barnacles brood in their first year is probably due to a combination of the time since settlement and size attained. In their second year after settlement, both species are multiple brooders, producing two broods during the summer season.