Genetic Structure and Diversity of the Moon Jellyfish Aurelia coerulea Polyp Population in Jaran Bay, Korea, Revealed by Mitochondrial COI and 16S rRNA Genes

Blooms of the moon jellyfish ( Aurelia coerulea ) have been responsible for huge economic losses and environmental disruptions in oceans around the world. The mass occurrence of these jellyfish may be highly related to the benthic polyp populations; however, studies supporting this are scarce. Here, we analyzed the genetic diversity and structure of Korean A. coerulea , using two mitochondrial genes, COI and 16S rRNA, in 51 polyps collected from Jaran Bay (South Korea) that is greatly affected by the mass occurrence of the jellyfish . Genetic diversity analysis identified 20 and 9 haplotypes in COI and 16S rRNA genes, respectively. TCS network analysis and haplotype distance matrix revealed a significant genetic structure in both genes. In addition, two distinct haplogroups (A and B) coexisted in Jaran Bay, and a single haplotype (COI-H4 or 16S-H2) dominated. These findings suggest a strong population differentiation among the polyp population that may have an effect on the jellyfish blooms in Jaran Bay.