Kazuya Nagasawa

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The following caryophyllidean tapeworms were found in freshwater fishes from Japan (species reported from Japan for the first time marked with an asterisk): family Caryophyllaeidae: Paracaryophyllaeus gotoi (Motomura, 1927) from Misgurnus anguillicaudatus (Cantor); Archigetes sieboldi Leuckart, 1878 from Pseudorasbora parva (Temminck et Schlegel) and(More)
The population size of the salmon louse, Lepeophtheirus salmonis, was monitored annually in the summers of 1991–1997 by examining six species of Pacific salmon (Oncorhynchus spp.) caught by surface long-lines in oceanic offshore waters of the North Pacific Ocean and Bering Sea. The annual copepod population size on all salmonids caught was estimated by(More)
A redescription is given of Raphidascaris gigi Fujita, 1928 based on newly collected specimens from the intestine of masu salmon Oncorhynchus masou (Brevoort) in the Kinu River in Japan. The species is characterised by the absence of interlabia and lateral alae, by the presence of lips without lateral membranous flanges and by numerous pre-anal and postanal(More)
Five species of philometrid nematodes (subfamily Philometrinae) are redescribed on the basis of newly collected materials from marine fishes from Japan. The species Philometra sciaenae Yamaguti, 1941, considered by Rasheed (1963) a synonym of P. lateolabracis (Yamaguti, 1935), is re-established as a valid species and the male of this nematode, collected(More)
Heliconema longissimum (Ortlepp, 1923) is an ecologically poorly known nematode found in the stomach of Japanese eels, Anguilla japonica Temminck and Schlegel. The occurrence of this nematode in Japanese eels was surveyed in 2 contiguous brackish-water areas (Misho Cove and the lower Renjoji River) of Ehime Prefecture, western Japan, during April 2008 to(More)
Gravid females of two species of philometrid nematodes (Philometridae) were collected from marine perciform fishes in Japanese waters, mainly from the southern Sea of Japan. Based on light microscopy and scanning electron microscopy examinations, the previously described but poorly known species Philometra cryptocentri Yamaguti, 1961 is redescribed from(More)
Two new copepod species of the genus Taeniacanthus Sumpf, 1871 (Cyclopoida: Taeniacanthidae) are described from boxfishes (Aracanidae and Ostraciidae) caught in the Indo-West Pacific region: T. larsonae n. sp. from Ostracion nasus Bloch in the Arafura Sea and off Australia and Tetrosomus concatenatus (Bloch) off Japan; and T. thackerae n. sp. from O.(More)
The first and third chalimus stages and chalimus adult (previously known as young adult) of Caligus latigenitalis are described based on new material collected from the body surface of a heavily infected wild blackhead seabream Acanthopagrus schlegelii schlegelii from Hiroshima Bay, Japan. The second and fourth chalimus stages of the same species are(More)
Interannual variations in abundance, timing of outmigration from rivers, growth rate and condition of juvenile chum salmon (Oncorhynchus keta) were studied in the Nemuro Strait (eastern Hokkaido, Japan) during 1999–2002 to establish a possible relationship to zooplankton abundance. The otolith microstructure of juveniles was examined each year in late June(More)
Five helminths, including a new echinorhynchid acanthocephalan Acanthocephalus longiacanthus n. sp., are described based on specimens from the giant mottled eel Anguilla marmorata Quoy & Gaimard caught in a small river, western Japan. The new acanthocephalan is distinguished from the other congeners in terms of hook arrangement (8–9 longitudinal rows with(More)