Kazuya Nagasawa

Hiroshima University | HU

Recent studies have reported that salmonids and ayu Plecoglossus altivelis altivelis (Temminck and Schlegel, 1846), both of which are salmoniform fishes, serve as important hosts for Argulus coregoni Thorell, 1864. These studies found the parasite in the upper and middle-lower reaches of large rivers, respectively, originating from high-elevation m...

Both ovigerous and non-ovigerous females of the cymothoid isopod Anilocra clupei Williams & Bunkley-Williams, 1986 were collected from the body surface of Japanese sardine Sardinops melanostictus (Temminck & Schlegel, 1846) in Aso-kai Lagoon, Kyoto Prefecture, central Japan. The isopod is redescribed herein based on the collected females. Japanese...

An ovigerous female of the cymothoid isopod Ceratothoa oxyrrhynchaena was collected from the buccal cavity of a yellow grouper Epinephelus awoara (Temminck & Schlegel, 1842) (Perciformes: Epinephelidae) in Wakasa Bay, an inlet of the southern Sea of Japan, off Obama, Fukui Prefecture, central Japan. This represents a new host record for C. oxyrrhyn...

An ovigerous female of Nerocila phaiopleura Bleeker, 1857 was found on one (prevalence, 0.7%) of 141 individuals of Japanese sardine Sardinops melanostictus (Temminck and Schlegel, 1846) from coastal waters of the western North Pacific Ocean off Mie Prefecture, central Japan, on 6 March 2015. The female was firmly attached using its dactyli to the...

Lernaeenicus ramosus Kirtisinghe, 1956 is a parasite of marine fishes in the Indo-West Pacific region. In Japan, this species has been reported from fishes in three families (Epinephelidae, Serranidae, and Pinguiperidae). In this study, we collected three metamorphosed females of L. ramosus from a grub fish Parapercis sexfasciata (Temminck & Schleg...

Japanese sardine, Sardinops melanostictus (Temminck and Schlegel, 1846), infected with Nerocila phaiopleura Bleeker, 1857, were collected in coastal waters of the western North Pacific Ocean near Cape Inubo, Chiba Prefecture, central Japan, in June 2024. Of 17 infected fish examined, 16 (94.1%) and one (5.9%) fish harbored one and two isopods, resp...

Adult females of the cymothoid isopod Anilocra clupei Williams and Bunkley-Williams, 1986 were collected from the body surface of Japanese sardinella Sardinella zunasi (Bleeker, 1854) (Clupeiformes: Dorosomatidae) from both a river mouth area of the Saba River flowing into the western Seto Inland Sea, and Kadogawa Bay, an inlet of the western North...

An adult male of Argulus japonicus Thiele, 1900 was found in a sample of zooplankton collected by horizontal towing of a plankton net in the near surface waters off the west coast (36º22′13.9″N, 140º27′15.9″E) of Lake Senba (33.2 ha, 1.2 m in maximum water depth), Mito City, Ibaraki Prefecture, central Japan, on 15 July 2023. The male is briefly de...

An adult male specimen of Argulus coregoni Thorell, 1864 was collected from the body surface of a dark chub Nipponocypris temminckii (Temminck and Schlegel, 1846) at 15 m elevation in a small stream in central Japan. The specimen collected is herein described and corresponds well to the descriptions of A. coregoni from European and East Asian count...

Eight postmetamorphic adult females of Lernaea cyprinacea Linnaeus, 1758 were collected from two (prevalence, 14.3%) of 14 adult Amur sticklebacks, Pungitius sinensis (Guichenot, 1869), in an irrigation canal at Sumiyoshi (43º55′02″N, 144º07′28″E) in Memanbetsu, Ozora, eastern Hokkaido, northern Japan, on 22 July 2021. Each infected fish harbored f...

A free-swimming ovigerous female of Argulus japonicus Thiele, 1900 was collected from a bucket of water which contained three live freshwater fishes caught by electrofishing in a small lake, Lake Shimo-Ezu (32º46′15″N, 130º45′06″E), Kumamoto City, Kyushu, western Japan on 4 July 2016. The fishes were individually identified as ayu Plecoglossus alti...

The pennellid copepod Lernaeenicus ramosus Kirtisinghe, 1956 is generally known as a parasite of groupers (Perciformes: Epinephelidae) in the Indo-West Pacific region including Japan. However, this parasite has also been reported from a non-ephinephelid fish in Japan, where it was found on the grub fish, Parapercis sexfasciata (Temminck and Schleg...

Two adult females of Argulus japonicus Thiele, 1900 were previously reported from a rosy bitterling Rhodeus ocellatus (Kner, 1866) (Cypriniformes: Cyprinidae: Acheilognathinae) in Kumamoto City, Kyushu, western Japan, but no morphological information was given. In this study, the two females are re-examined for their morphology. They are identical...

The cymothoid isopod Ceratothoa verrucosa (Schioedte and Meinert, 1883) is a buccal-cavity parasite of sparid fishes in Japanese waters. Recently, we collected a pair of an ovigerous female and an adult male of this isopod from a red seabream Pagrus major (Temminck and Schlegel, 1843) purchased in the fresh fish section of a supermarket in Fukui Ci...

One and two specimens of Argulus japonicus Thiele, 1900 were collected from the body surface of big-scaled redfin Pseudaspius hakonensis (Günther, 1877) (Cypriniformes: Leuciscidae) in the Babame River, Akita Prefecture, and Lake Jusan, Aomori Prefecture, northern Honshu, Japan, respectively. This is two new prefecture records in Japan and a new ho...

Two post-metamorphic adult females of the sphyriid copepod Lophoura cornuta (C. B. Wilson, 1919) were collected from Kaup's arrowtooth eel Synaphobranchus kaupii Johnson, 1862 (Anguilliformes: Synaphobranchidae) at two deep-sea sites in the western North Pacific off the south coast of Hokkaido, northern Japan. This paper reports on the morphology o...

Argulus coregoni Thorell, 1864 was collected from two species of fishes in small mountain streams in Akita Prefecture, northern Honshu, Japan. The infected fishes are ayu Plecoglossus altivelis altivelis (Temminck and Schlegel, 1846) (Plecoglossidae) from the Nukazawa River and stream-resident masu salmon Oncorhynchus masou masou (Brevoort, 1856) (...

One adult male of Argulus japonicus Thiele, 1900 was collected from the body surface near the pectoral fin of a koi carp Cyprinus carpio Linnaeus, 1758 (Cypriniformes: Cyprinidae) reared by a carp hobbyist in a garden pond in Akiota, Hiroshima Prefecture, western Honshu, Japan. The male collected is briefly described. This is the second specimen-...

Examination of Japanese eels Anguilla japonica Temminck & Schlegel, 1846 from Kadota Reservoir, Fukuoka Prefecture, western Japan, revealed the infection by Argulus mongolianus Tokioka, 1939 in the eel buccal cavity. This is the second record of A. mongolianus in Japan and extends its distributional range from Miyagi Prefecture, northern Honshu, so...

In total, 78 specimens of Argulus japonicus Thiele, 1900 were collected fishes reared in Shiga Prefecture, central Japan, and have been deposited at the Lake Biwa Museum (LBM) in Kusatsu of the same prefecture. Sixty-three specimens were taken from four species of fishes, including silver crucian carp Carassius sp., unidentified crucian carp Carass...

Two female specimens of argulid branchiuran were found in the collection of the Lake Biwa Museum, Kusatsu, Shiga Prefecture, central Japan. These specimens were collected in Matsunoike Pond within the Expo’70 Commemorative Park in Suita, Osaka Prefecture, central Japan, on 17 October 1987. Although they were found in bad condition, they have a sing...

Argulus japonicus Thiele, 1900 and Argulus coregoni Thorell, 1864 are ectoparasites of freshwater fishes and are known to occur in Lake Biwa and its adjacent inland waters in Shiga Prefecture, central Japan. Since these parasites are not common in the wild in Japan, this study examined the specimens loaned from the Lake Biwa Museum and those previo...

Argulus nobilis Thiele, 1904 is an ectoparasite of gars (Lepisosteidae) in the U.S.A. Five female specimens of A. nobilis were found in the collection of the Lake Biwa Museum, Japan. This is the first record of the species from Japan and outside the U.S.A. The specimens were collected from an unidentified gar and shortnose gar, Lepisosteus platosto...

Neoergasilus japonicus , a fish ectoparasite indigenous to eastern and southern Asia, has been introduced to various regions, including Europe and North and South America, where it spreads at an alarming rate. The parasite is not host‐specific. It was also collected from the Vaal‐Orange and Limpopo river systems in South Africa. This report describ...

An argulid branchiran is known to infect carp Cyprinus carpio Linnaeus, 1758 farmed in Okayama Prefecture, western Japan, but no species identification has been made to date. A male of Argulus japonicus Thiele, 1900 was collected from the body surface of a pale chub Opsariichthys platypus (Temminck & Schlegel, 1846) (Cyprinidae) in the Seno-o River...

Salmincola californiensis is a parasitic copepod of freshwater salmonids in the North Pacific rim countries. Sixteen adult females of the species were found alive on the gills of an ocean-age 4, maturing steelhead trout, Oncorhynchus mykiss, caught in offshore waters (50º30′N, 179º30′W) of the North Pacific Ocean in July 1997. This is the first evi...

Morphological characters of female and male Argulus japonicus Theile, 1900 are reported using three specimens (one female and two males) collected from a common carp Cyprinus carpio Linnaeus, 1758 (Cypriniformes: Cyprinidae) in Lake Izunuma (38º43'09"N, 141º06'09"E), Miyagi Prefecture, northern Honshu, Japan. The specimens are particularly characte...

Two specimens of Argulus japonicus Theile, 1900 were collected from a silver crucian carp Carassius sp. (Cypriniformes: Cyprinidae) in the middle reaches of the Kurose River at Misono-u (34°23′56″N, 132°44′23″E) in Higashi-Hiroshima, Hiroshima Prefecture, western Honshu, Japan, on 10 May 2006. These specimens, comprising one female and one male, we...

An ovigerous female specimen of a freshwater fish parasite Argulus coregoni Thorell, 1864 was found in the collection of the Lake Biwa Museum, Kusatsu, Shiga Prefecture, central Japan. This specimen was collected as a detached individual by a small trap net installed for a fish fauna study in the middle reaches of the Nagara River at Hotoshima (no...

The cystidicolid nematode Salvelinema walkeri (Ekbaum, 1935) is a swim bladder parasite of freshwater salmonids in western North America, ranging from northern California to southern British Columbia. This parasite was found from two age-2.0, juvenile coho salmon Oncorhynchus kisutch (Walbaum, 1792) caught in the southern central Gulf of Alaska in...

Markevitchielinus anchoratus Titar, 1975 is reported based on an adult female from the floor of the buccal cavity of a sea raven Hemitripterus villosus (Pallas, 1814) caught in Onagawa Bay, an inlet of the Northwestern Pacific Ocean, Miyagi Prefecture, northern Japan. The female specimen is briefly described. The female inserted its head with a pai...

An ovigerous female and an adult male of the cymothoid isopod Ceratothoa verrucosa (Schioedte and Meinert, 1883) were found in the buccal cavity of a crimson seabream Evynnis tumifrons (Temminck and Schlegel, 1843) purchased in the fresh fish section of a supermarket in Fukui City, Fukui Prefecture, central Japan. The crimson seabream harboring the...

An ovigerous female of a freshwater fish parasite Argulus coregoni Thorell, 1864 was collected in the middle reaches of the Naruse River at Sanbongi-Saida, Osaki, Miyagi Prefecture, northern Honshu, Japan. The female was found on the body surface of one Japanese barbel [Hemibarbus barbus (Temminck and Schlegel, 1846)] among 177 individuals composin...

The occurrence of the copepod parasite Lernaea cyprinacea Linnaeus on bluegill Lepomis macrochirus Rafinesque was studied in late May for six years, from 2011 to 2016, in Budo Reservoir within the campus of Hiroshima University in Higashi-Hiroshima, Hiroshima Prefecture, Japan. Bluegill was introduced in 1960 from the United States to Japan, where...

The pennellid copepod Lernaeenicus ramosus Kirtisinghe, 1956 is a marine fish parasite in the Indo-West Pacific region. Serranid fishes (Perciformes) are the major hosts of L. ramosus, and as its non-serranid host, a single blenniid fish (Blenniiformes) is known from Australia. A metamorphosed ovigerous female of L. ramosus was collected from a gru...

Toyama Bay is an inlet of the southern Sea of Japan, and its coastal water is known as the locality where two paratypes of Mothocya parvostis Bruce, 1986 were collected from Japanese halfbeak, Hyporhamphus sajori (Temminck and Schlegel, 1846). In this study, 13 ovigerous females of Mothocya sp. were collected from the branchial cavity of 16 individ...

An ovigerous female of cymothoid isopod was collected in June 2021 from the branchial cavity of a Japanese halfbeak, Hyporhamphus sajori (Temminck and Schlegel, 1846), in coastal waters of the Sea of Okhotsk at Yubetsu, Hokkaido, northern Japan. This female's body length (21.2 mm) falls within the range of that (20.5-27.5 mm) of Mothocya sajori Bru...

Specimens (10 ovigerous females and nine adult males) of cymothoid isopod were collected in October 2022 from the branchial cavity of Japanese halfbeak, Hyporhamphus sajori (Temminck and Schlegel, 1846), in coastal waters of Tsuruga Bay, an inlet of the southern Sea of Japan, Fukui Prefecture, central Japan. Prevalence of isopod infection was 36% (...

Argulus coregoni Thorell, 1864 was collected from the body surface of ayu, Plecoglossus altivelis altivelis (Temminck and Schlegel, 1846), in the middle reaches of the Toyo River at Kiyosaki-Yokohata in Shitara, Aichi Prefecture, central Japan. One of five ayu examined was infected with two (male and female) adults of A. coregoni. This collection r...

Sixteen metamorphosed females of a mesoparasitic copepod Lernaeenicus ramosus Kirtisinghe, 1956 were collected from a Hong Kong grouper, Epinephelus akaara (Temminck and Schlegel, 1842), at 50 m deep in Toyama Bay, an inlet of the Sea of Japan, off Hime, Noto, Ishikawa Prefecture, central Japan. The copepod is briefly described. In the Sea of Japan...

Specimens of the coastal marine fish leech Limnotrachelobdella okae (Moore, 1924) were collected from the pelvic fins and lateral body surface of big-scaled redfin, Pseudaspius hakonensis (Günther, 1877), in two brackish water lakes, Lake Tofutsu and Lake Abashiri, on the Sea of Okhotsk coast, Hokkaido, northern Japan. The external morphology of th...

An adult female of Argulus matuii Sikama, 1938 was collected from the body surface of a crescent sweetlips Plectorhinchus cinctus (Temminck & Schlegel, 1843) in coastal waters of the Northwestern Pacific Ocean near Minabe, Wakayama Prefecture, central Japan. This represents a new host record for A. matuii. The female is briefly described, and the s...

Postmetamorphic ovigerous females of the mesoparasitic copepod Lernaea cyprinacea Linnaeus, 1758 (Lernaeidae) were collected from medaka, Oryzias latipes (Temminck and Schlegel, 1846) (Beloniformes: Adrianichthyidae), in Yahara Reservoir on Nakanoshima Island, one of the Oki Islands, located in the southern Sea of Japan off Shimane Prefecture, wes...

Six adult specimens of Ceratothoa oxyrrhynchaena Koelbel, 1878, were collected from the buccal cavity of three individuals of blackthroat seaperch, Doederleinia berycoides (Hilgendorf, 1879), at 150 m deep on the continental shelf of Toyama Bay, an inlet of the southern Sea of Japan, Ishikawa Prefecture, central Japan, in August 2022. Each fish was...

Argulus coregoni Thorell, 1864 was collected from the body surface of ayu, Plecoglossus altivelis altivelis (Temminck and Schlegel, 1846), in the Asuwa River, a tributary of the Hino River, one of the major Kuzuryu River tributaries, in Fukui Prefecture, central Japan in July 2022. Four (14.8%) of the 27 ayu examined were each infected by a single...

Two copepod parasites, Salmincola edwardsii (Olsson, 1869) and S. markewitschi Shedko & Shedko, 2002, were collected from salmonids in eastern Hokkaido, Japan: these copepods were taken from whitespotted char, Salvelinus leucomaenis (Pallas, 1814), and brook trout, S. fontinalis (Mitchill, 1814) in the Nishibetsu River, and Salmincola edwardsii fro...

Visceral adhesions are found in sockeye salmon Oncorhynchus nerka in the North Pacific Ocean and adjacent regions. The disease is induced as the result of a host reaction associated with the migration of the freshwater philonematid nematode Philonema oncorhynchi from the host tissues to the body cavity. In this paper, 928 individuals of sockeye sal...

Ceratothoa oxyrrhynchaena Koelbel, 1878 is a buccal cavity parasite of marine fishes. An ovigerous female and an adult male of the species were collected from a frozen-thawed yellowback sea-bream, Dentex hypselosomus Bleeker, 1854, purchased in the fresh fish section of a local supermarket in Asahikawa, Hokkaido, northern Japan. The female and the...

Two specimens of Ceratothoa verrucosa (Schioedte and Meinert, 1883) were collected from the buccal cavity of a red seabream, Pagrus major (Temminck and Schlegel, 1843), purchased in the fresh fish section of a local supermarket in Toyama City, Toyama Prefecture, central Japan. The specimens consisting of an ovigerous female and an adult male are...

A non-ovigerous female of Ceratothoa oxyrrhyn-chaena Koelbel, 1878 was collected from the buccal cavity of a blackthroat seaperch, Doederleinia berycoides (Hilgendorf, 1879), at 250 m deep on the continental shelf of Suruga Bay, an inlet of the Northwestern Pacific Ocean, central Japan. No male was found in the buccal cavity of the fish examined un...

Four specimens (two ovigerous females and two adult males) of Ceratothoa oxyrrhynchaena Koelbel, 1878 were collected from the buccal cavity of two adult blackthroat seaperch, Doederleinia berycoides (Hilgendorf, 1879), reared in a tank at the Fisheries Research Institute, Toyama Prefectural Agricultural, Forestry and Fisheries Research Center, Name...

Both adult females and males of Argulus mongolianus Tokioka, 1939 were collected from the buccal cavity wall and body surface of freshwater fishes in Lake Izunuma and Lake Uchinuma, Miyagi Prefecture, northen Honshu, Japan. The original description of the species was insufficient, based on a single female from Inner Mongolia, China, and no further...

Argulus coregoni Thorell, 1864 was collected from white-spotted char, Salvelinus leucomaenis (Pallas, 1814), red-spotted masu salmon, Oncorhynchus masou ishikawae Jordan and McGregor, 1925, masu salmon, O. m. masou (Brevoort, 1856), and a hybrid between white-spotted char and masu salmon in mountain streams, Gifu Prefecture, central Japan. The host...

An ovigerous female of Argulus matuii Sikama, 1938 was collected from the body surface of a yellowfin seabream Acanthopagrus latus (Houttuyn, 1782) in a cove facing the Bungo Channel off Ehime Prefecture, western Japan. This represents a new host record for A. matuii, and the female collected is herein described. This female, which was fixed and pr...

Specimens of Ceratothoa verrucosa (Schioedte and Meinert, 1883) were collected from the buccal cavity of a red seabream, Pagrus major (Temminck and Schlegel, 1843), and a crimson seabream, Evynnis tumifrons (Temminck and Schlegel, 1843), in coastal waters of the Northwestern Pacific Ocean off Mie Prefecture, central Japan. The collection of C. ver...

Sixteen adult females of the lernaeopodid copepod, Pseudocharopinus markewitschi (Gusev, 1951), were collected from the skin of a mottled skate, Beringraja pulchra (Liu, 1932), in the southern Sea of Japan off Gotsu, Shimane Prefecture, western Japan. This represents the second record of P. markewitschi from the Sea of Japan off the Japanese coast....

The pennellid copepod Lernaeenicus ramosus Kirtisinghe, 1956 is a parasite of perciform and blenniiform fishes in the Indo-West Pacific region. A metamorphosed female of the species was collected from a perchlet, Chelidoperca hirundinacea (Valenciennes, 1831), caught on the neritic continental shelf of Suruga Bay, central Japan. The copepod is almo...

The information on the nematodes of freshwater fishes of Japan published between 1905 and 2016 was assembled as a checklist in 2016 and 2017. The present paper updates the checklist based on the literature published between 2017 and 2021 and includes information on 12 nominal species and some unidentified species. The 12 nominal species belong to t...

Five individuals (four males and one ovigerous female) of the branchiuran argulid Argulus matuii Sikama, 1938 were collected from the body surface of a white trevally, Pseudocaranx dentex (Bloch and Schneider, 1801), in the Northwestern Pacific Ocean off Ohara, Chiba Prefecture, central Japan. After these individuals were frozen for 41 days, they w...

Tachaea chinensis Thielemann, 1910 is an ectoparasite of freshwater shrimps and prawns in East Asia. Japan is located at the northern limit of the geographical distribution of the species, but much remains poorly studied on its distribution in northern Japan, where it has been reported only from Aomori Prefecture, the northernmost region on Honshu...

Two metamorphosed females of Lernaeenicus ramosus Kirtisinghe, 1956 were collected from an areolate grouper, Epinephelus areolatus (Forsskål, 1775), in Kagoshima Bay, an inlet of the western North Pacific Ocean, Kagoshima Prefecture, southern Japan. The anterior body of each female was embedded in the host's musculature, and the trunk protruded ext...

The blue mackerel Scomber australasicus is one of the major commercial fishes consumed in southern Japan. Three species of parasitic copepods were collected from S. australasicus in the East China Sea off the west coast of Kyushu Island, southern Japan. These copepods are each characterized based on the females: Pumiliopes scombri (Bomolochidae) di...

An adult female of Argulus coregoni Thorell, 1864 was collected from the body surface of a white-spotted char, Salvelinus leucomaenis (Pallas, 1814), in the upper reaches of the Maze River, a tributary of the Hida River draining into the Nagara River, Gifu Prefecture, central Japan. This represents the first record of A. coregoni from a wild salmon...

Largemouth bass Micropterus salmoides (Lacepède, 1802) was introduced from North America into Japan in 1925 and 1972. The fish has spread extensively since the late 1960s and is now found in all prefectures of Japan. An adult female of the argulid branchiuran Argulus japonicus Thiele, 1900 was collected from the body surface of a largemouth bass in...

An ovigerous female of a fish ectoparasite Argulus caecus C. B. Wilson, 1922 was collected from a squid, probably Todarodes pacificus (Steenstrup, 1880), from a fixed net installed in Otsuchi Bay, an inlet of the northwestern Pacific Ocean, Iwate Prefecture, northen Japan. Since the original description of A. caecus was insufficient, this paper rep...

Eight individuals of the piscicolid leech Pontobdella macrothela Schmarda, 1861 were collected from the buccal cavity of a Japanese bullhead shark, Heterodontus japonicus Miklouho-Maclay & Macleay, 1884 (Elasmobranchii: Heterodontidae), in Okada Port, Izu-Oshima Island (the northwestern Pacific), central Japan. This collection represents the first...

Two individuals (one ovigerous female and one male) of the cymothoid isopod Nerocila japonica Schioedte & Meinert, 1881 were found on the left pectoral fin of a yellowfin seabream, Acanthopagrus latus (Houttuyn, 1782), in coastal waters of Hiroshima Bay, an inlet of the western Seto Inland Sea, Hiroshima Prefecture, Japan. The fin was seriously dam...

Freshwater sculpins (Perciformes: Cottidae) are uncommon hosts of the lernaeid copepod Lernaea cyprinacea Linnaeus, 1758 worldwide, with its only one record from those sculpins (i.e., from the bullhead, Cottus gobio Linnaeus, 1758, in Scotland, U.K.). One and two postmetamorphic adult females of L. cyprinacea were collected each from two individual...

Lake Biwa is the largest and ancient lake in Japan. The parasite fauna of aquatic animals of the lake has been extensively studied, but little information is available on the biology of fish-parasitic branchiurans. Two adult males of the argulid branchiuran Argulus japonicus Thiele, 1900 were collected from the body surface of an individual of the...

A lernaeid copepod, Lamproglena chinensis Yü, 1937, is redescribed based on the newly collected specimens from the snakehead Channa argus (Cantor) (Actinopterygii: Perciformes: Channidae) caught in Lake Imuta, Satsumasendai, Kagoshima Prefecture, Kyushu, southern Japan and the type specimens of L. ophiocephali Yamaguti, 1939, a junior synonym of L....

Specimens of two species of lernaeopodid copepods, Salmincola edwardsii (Olsson, 1869) and Salmincola markewitschi Shedko and Shedko, 2002, were collected from chars (Salvelinus spp.) reared in exhibition tanks of the Sapporo Salmon Museum, Hokkaido, Japan. Descriptions of these copepods are provided using the specimens. In 1988, adult females of S...

Ovigerous females of the lernaeopodid copepod Salmincola stellata Markevich, 1936 were collected in April 2021 from Japanese huchen, Parahucho perryi (Brevoort, 1856) (Salmonidae), held in a tank at the Yama No Aquarium in Kitami, Hokkaido, northern Japan. All of 13 Japanese huchen examined (80–120 cm in total length) were individually infected wit...

An adult female of the argulid branchiuran Argulus coregoni Thorell, 1864 was collected from the dorsal body surface of an oily bitterling, Tanakia limbata (Temminck and Schlegel, 1846) (Cyprinidae: Acheilognathinae), in the lower reaches of the Asahi River, Okayama Prefecture, western Japan. This represents a new host record for A. coregoni and it...