The fish louse <i>Argulus coregoni</i> from <i>Oncorhynchus masou ishikawae</i> (Salmonidae) cultured in Shikoku, western Japan, with a list of occurrence records of <i>A. coregoni</i> from fishes reared in Japan

Abstract

Argulus coregoni Thorell, 1864 is briefly described based on specimens from the body surface of amago salmon, Oncorhynchus masou ishikawae Jordan & McGregor, 1925, cultured at a trout farm in Tokushima Prefecture, Shikoku, western Japan. This represents the first confirmed record of A. coregoni from farmed salmonids in Shikoku. A list of occurrence records of A. coregoni from fishes reared in Japan is also provided based on the literature published between 1950 and 2019. The species has so far been reported from three species and two subspecies of salmonids and one species of plecoglossid reared at 14 sites in 10 prefectures (Tochigi, Tokyo, Nagano, Ishikawa, Gifu, Aichi, Wakayama, Hyogo, Tokushima, and Yamaguchi). Most of these sites were governmental or research facilities, and it is evident that little attention has been paid to A. coregoni at commercial tout farms. The species is considered to occur at more trout farms in Japan.

Occurrence of a Skin Parasite <i>Argulus coregoni</i> (Branchiura: Argulidae) on Salmonids in Mountain Streams, Central Japan, with Discussion on Its Longitudinal Distribution and Host Utilization in Rivers

“…The argulid branchiuran Argulus coregoni Thorell, 1864 is a skin parasite of freshwater fishes in northern Europe and eastern Asia (Neethling and Avenant-Oldewage 2016). In Japan, the species infects wild fishes belonging to five families; Salmonidae, Plecoglossidae (both Salmoniformes), Cyprinidae (Cypriniformes), Amblycipitidae (Siluriformes), and Odontobutidae (Gobiiformes) (e.g., Tokioka 1936;Yama guti 1937;Nagasawa and Kawai 2008;Nagasawa 2009Nagasawa , 2011Nagasawa et al 2014;Nagasawa and Ishikawa 2015;Nagasawa and Taniguchi 2021) but is also found on farmed salmonid and plecoglossid fishes (Hoshina 1950;Nagasawa and Yuasa 2020). Its larval development, host associations, impacts on host fishes, and treatment have all been studied (Inoue et al 1980;Shimura and Egusa 1980;Shimura 1981Shimura , 1983Shimura et al 1983a, b;Shimura and Inoue 1984;Kata hira et al 2021).…”

Redescription of <i>Argulus mongolianus</i> (Crustacea: Branchiura: Argulidae), an Ectoparasite of Freshwater Fishes in East Asia, with Its First Record from Japan

“…coregoni Thorell, 1864. These branchiurans are important parasites of farmed fishes as well, and their biology has been extensively studied in Japan [e.g., Nakazawa (1914), Tokioka (1936a), Kimura (1970), and Ikuta and Makioka (1997) for A. japonicus; Hoshina (1950), Shimura (1981Shimura ( , 1983, Nagasawa and Yuasa (2020), and Katahira et al (2021) for A. coregoni].…”

<i>Argulus japonicus</i> (Branchiura: Argulidae) parasitic on largemouth bass <i>Micropterus</i> <i>salmoides</i> in Japan, with the morphology of the adult female of the argulid

“…Argulus japonicus is morphologically similar to Argulus coregoni Thorell, 1864, which also occurs in east/southeast Asia, including Japan (e.g., Tokioka, 1936;Yamaguti, 1937;Hoshina, 1950;Nagasawa & Yuasa, 2020;Nagasawa & Taniguchi, 2021), Russian Far East (e.g., Dogiel & Akhmerov, 1952Smirnova, 1971;Gusev, 1987;Ermolenko, 2004;Sokolov et al, 2012), China (e.g., Wang, 1958;Institute of Hydrobiology, Hubei Province, 1973;Kuang & Qian, 1991;Yang, 2009), and Malaysia (Everts & Avenant-Oldewage, 2009). Argulus japonicus is distinguished from A. coregoni by having an apically rounded abdomen (Fig.…”