Amphibalanus variegatus is an intertidal barnacle with a wide distribution across Indo-West Pacific including Indonesia. However, the geographical dispersal history and the population connectivity of this species has never been studied. This study was aimed to determine 1) the genetic diversity among populations of A. variegatus from different geographical locations, 2) the geographic dispersal history of A. variegatus in the study area, and 3) the population genetic connectivity of A. variegatus in the study area. This research was a survey with purposive sampling technique used to collect samples. The A. variegatus population with the highest genetic diversity was Lombok with nucleotide diversity value of 0.088 ± 0.067 and the haplotype diversity parameter (h) value of 1.000 ± 0.272. The A. variegatus geographical dispersal indicated by genetic distance suggesting the Oikebajomae was the ancestral population spread into Manila population via Luzon strait and into the Philippines archipelago via the Mindoro strait pathway. The A. variegatus population of Oikebajomae, Manila, and Tasmania populations has very low connectivity based on the gene flow value parameter (Nm) of 0.04 indicating geographic isolation by distance among populations.

Sri Riani

Romanus Edy Prabowo

Erwin Riyanto Ardli