Identification of spawning sites of the tiger puffer Takifugu rubripes in Nanao Bay, Japan, using DNA analysis

There are two possible spawning sites of the tiger puffer Takifugu rubripes near Nanao Bay in the Sea of Japan: one near Hachiro Lagoon, approximately 390 km northeast of Nanao Bay, and another in Wakasa Bay, approximately 170 km west of Nanao Bay. Tagging research suggests that these two spawning sites represent different subpopulations. In the present study, Nanao Bay spawning sites were identified by mitochondrial DNA control region sequencing of eggs collected using a sledge net in May and June of 2009. The spawning sites were distributed in a small region with a sandy bottom at a depth of 17.5–20.5 m (water temperature 13.07–16.56 °C, salinity 33.95–34.12). The population structure of T. rubripes around Nanao Bay was also investigated using DNA analysis of mature adult samples from three locations. Genetic differentiation was not significant among the adults, suggesting the presence of gene flow resulting from broad dispersal of individuals from the three locations.