2025 Volume 20 Issue 1 Pages 36-45
The giant Pacific octopus (Enteroctopus dofleini) is the world’s largest octopus and the most abundant species in coastal waters of the North Pacific. Despite the commercial importance of this species in Japan, studies of its genetic population structure have been limited to the Gulf of Alaska. This study was conducted to clarify the genetic diversity and population structure of the giant Pacific octopus (Enteroctopus dofleini) in Japan and evaluate genetic differences in this species between the northwest Pacific (NWP) and northeast Pacific (NEP) based on analyses of the mitochondrial cytochrome c oxidase subunit I (CO1) and cytochrome b (Cytb) genes. A total of 263 specimens were collected in Japan (NWP) during June 2020–August 2022, and the CO1 and Cytb genes were successfully sequenced and analyzed in 230 and 229 specimens, respectively. Diversity indices were also calculated for the NEP using previously published sequence data, and genetic variance was compared between the NEP and NWP. In Japan, ten CO1 haplotypes and nine Cytb haplotypes were detected, and genetic variation among sites was not significant. Comparisons of genetic diversity between the NWP and NEP were inconclusive, but clear genetic differentiation was found between the two regions. The genetic population structure of E. dofleini has likely been shaped by dispersal during the planktonic paralarval stage and plausibly by changes in climate that occurred during the Last Glacial Maximum.
