Molecular phylogenetics and population demographic history of Amphioctopus fangsiao, inferred from mitochondrial and microsatellite DNA markers

Amphioctopus fangsiao (Cephalopoda: Octopodidae) is an important commercial species in the coastal waters of China. In recent years, however, the resource of A. fangsiao have declined because of habitat destruction and overfishing. To analyze the genetic variations of A. fangsiao caused by the fluctuation of resources, the population genetic structure of nine sampling locations collected from the Bohai Sea to the South China Sea were investigated, using mtDNA COI fragments and microsatellite DNA. The results of F-statistics, AMOVA, STRUCTURE and PCA analyses showed three phylogeographic clades (Clades A, B and C), revealing limited genetic exchange between north and south populations. These clades diverged in 2.23 (Clades A and B) and 3.67 (Clades A, B and C) million years ago, during the dramatic environmental fluctuations, such as sea level and temperature changes, have exerted great influence on the survival distribution pattern of global organisms. Our results for low genetic connectivity among A. fangsiao populations provide insights into the development of management strategies, that is, to manage this species as separate management unit.