Genetic diversity in wild and cultured populations of Rhopilema esculentum inferred from mitochondrial COI sequences

To investigate the genetic diversity and structure of different populations of the edible jellyfish Rhopilema esculentum , we amplified and sequenced the mitochondrial COI gene of three populations (two wild and one cultured). A total of 730 bp consensus sequences were obtained from 37 individuals, revealing 27 haplotypes. Except for Hap13, which was shared between the Pinghu (PH) and Huanghua (HH) populations, the remaining 26 haplotypes were private. All populations exhibited high haplotype diversity (0.978-1.000) and nucleotide diversity (0.07443-0.22682). AMOVA indicated that most genetic variation resided within populations (51.67%), yet extremely significant genetic differentiation occurred among them (F ST = 0.48335, p < 0.01). Neutrality tests analyses suggested that only the HH population shows signs of demographic expansion, whereas no significant expansion signal is detected in other populations. Furthermore, the private haplotypes identified here can be developed into COI-based, species-specific markers for population assignment, providing a valuable tool for evaluating stock-enhancement success, resource management, population monitoring, and molecular ecological studies of R. esculentum .