Phylogeography of the yellowfin goby Acanthogobius flavimanus in native and non-native distributions

Species introductions have been recognized as one of the principal threats to marine environments worldwide. Comparison of genetic data between native and non-native populations can provide key information, such as origin and population demography during the colonization process, which assists in understanding the mechanisms of invasion success in marine environments. The yellowfin goby, Acanthogobius flavimanus, is a large goby native to northeastern Asia, typically inhabiting muddy bottoms of bays, estuaries, and rivers, and is considered a pest where it has invaded coastal areas of the United States and Australia. Here, we analyzed mitochondrial DNA control region sequences of several yellowfin goby populations from both native and non-native distributions. The phylogenetic tree showed no intra-specific lineages, which is in contrast with previous phylogeographic studies that have shown deep genetic divergence in other coastal marine gobies around the Japanese archipelago. On the other hand, at the population level, we found significant genetic differentiation between northern and southern groups in the native distribution, which may be attributed to a rapid population expansion event of the southern group. Our analyses suggest that the origin of the northern California population is Tokyo Bay, but we were unable to identify the original source populations of the southern California and Melbourne populations. These populations showed greatly differing genetic diversities, suggesting their different demographic histories. This study contributes a new perspective on the genetic diversity of multiple populations of the yellowfin goby, as well as representing an example of the relationships between genetic diversity and invasion success.