長野県の木曽川上流域にある王滝川は，ヤマメナガクビムシSalmincola californiensis のアジアにおける分布南限地であるとともに，本種の異名であるSalmincola yamameのタイプ産地である．今回，王滝川本流と3支流（上黒沢，西野川，中沢川）でアマゴとヤマトイワナを採集し，本種の寄生状況を調べたところ，上黒沢で得たアマゴに本種の寄生を認めた．これは王滝川における本種の64年ぶりの再発見である．ヤマトイワナに本種の寄生は見られなかった．Salmincola yamameの記載時にヤマメと報告された宿主名は誤りで，正しくはアマゴであることを示した．

The Ôtaki River, a tributary of the upper Kiso River in central Japan, is the type locality of Salmincola yamame, a junior synonym of Salmincola californiensis, and is the southernmost locality of the species in Asia. A survey on the occurrence of S. californiensis parasitic on landlocked salmonids was conducted in the main stream and three tributaries (Kami-Kurosawa Stream, Nishino River, and Nakazawa River) of the Ôtaki River in June 2017. Female specimens of S. californiensis were collected from amago Oncorhynchus masou ishikawae in the Kami-Kurosawa Stream. This represents a rediscovery of Salmincola californiensis from the Ôtaki River. Yamato charr Salvelinus leucomaenis japonicus were not infected. The host species in the original description of S. yamame was misidentified as “yamame, a landlocked form of Oncorhynchus masou” and should be corrected as amago O. masou ishikawae.