“…Hatchery‐reared fish have been released into many rivers in Japan to enhance the fish stocks available to local fishermen and recreational anglers. However, the genetic integrity and diversity of masu salmon have often been ignored, sometimes resulting in accelerated hybridisation between wild and hatchery fish both within subspecies (Kawamura, Furukawa, Kubota, & Harada, ; Kawamura, Kubota, Furukawa, & Harada, ) and among subspecies (Kitanishi, Mukai, Yamamoto, Tago, & Oda, ; Yamazaki, Shimada, & Tago, ). In addition, habitat fragmentation by artificial damming is frequent in Japanese and Taiwan rivers, resulting in decreased population sizes and reduced genetic diversity of salmonid populations (Kitanishi, Yamamoto, Edo, & Higashi, ; Yamamoto, Kubota, Hasegawa, & Nakamura, ; Yamamoto et al, ).…”