Reproduction and recruitment of the barnacle Chthamalus montagui at Aberystwyth (mid-Wales)

Abstract

Data on the recruitment of Chthamalus montagui were collected over the 7 yr period 1979-85 at a site in Wales close to the species northern geographic limit. When compared with data from southerly sites they show that the breeding period, the period of larval settlement, and the density of recruits are all reduced in the northern part of the species range. It is proposed that competition with Semibalanus balanoides , which Connell (1961) suggested sets the northern limitof C. montagui , can only act to intensify the effects of a restricted breeding period and the consequential low level of larval recruitment.