Hirotaka Katahira

Hiroshima University, Hirosima, Hiroshima, Japan

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Publications (6)5.58 Total impact

  • Hirotaka Katahira, Kazuya Nagasawa
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    ABSTRACT: 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 5-6 hooks per row) on proboscis, maximum length of hook blade (81-95 μm in male, 150-190 μm in female), lemnisci being longer than proboscis receptacle, and small-sized eggs (80-83 μm). Two monogeneans, Pseudodactylogyrus anguillae (Yin & Sproston, 1948) and P. bini (Kikuchi, 1929), and two acanthocephalans, Acanthocephalus gotoi Van Cleave, 1925 and Southwellina hispida (Van Cleave, 1925), were also found; this new material is described. The monogeneans are notorious as invasive parasites spreading worldwide via anthropogenic transportations of anguillid eels, but in Japanese waters A. marmorata appears to be an indigenous host for these parasites. Anguilla marmorata is a new host record for the acanthocephalans A. gotoi and S. hispida.
    Systematic Parasitology 05/2014; 88(1):91-102. · 1.26 Impact Factor
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    ABSTRACT: With technological improvements in otolith microchemical analysis, the flexible use of habitat from coastal marine to fresh waters has been discovered in Japanese eels Anguilla japonica. We examined the occurrence of 3 congeneric gill monogeneans-Pseudodactylogyrus anguillae, P. bini, and P. kamegaii-on wild Japanese eels, in relation to the host's flexibility. From April 2008 to October 2009, 114 eels were collected from a brackish-water cove and 2 rivers flowing into the cove in Ehime Prefecture, western Japan. Based on otolith microchemical analysis, the eels were discriminated according to the following 4 types of habitat use: freshwater residents (Type I), individuals utilizing low-salinity habitats (Type II), downstream habitat-shifters (Type III), and cove residents (Type IV). P. anguillae occurred mainly on Type I and II eels, while P. bini was primarily found on Type I eels. In contrast, P. kamegaii occurred mainly on Type III and IV eels. Thus, we conclude that species composition and infection levels of Pseudodactylogyrus spp. clearly differed with habitat-use patterns of Japanese eels. Also, since P. anguillae was scarcely found on either Type III or IV eels, this study suggests that previous identifications of monogeneans collected from European brackish-water localities as P. anguillae may require verification.
    Diseases of Aquatic Organisms 08/2012; 100(1):43-9. · 1.73 Impact Factor
  • Hirotaka Katahira, Kazuya Nagasawa
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    ABSTRACT: Echinorhynchus hexagrammi Baeva, 1965 is redescribed on the basis of specimens collected from the saffron cod Eleginus gracilis (Tilesius) in Akkeshi Bay (western North Pacific) off Hokkaido, Japan. Eighteen museum specimens deposited as E. salmonis Müller, 1784 from Japanese coastal waters were also re-examined and re-identified as E. hexagrammi. Hexagrammos stelleri Tilesius, Hemitripterus villosus (Pallas), Podothecus sachi (Jordan & Snyder), Sebastes oblongus Günther and Verasper moseri Jordan & Gilbert are recognised as new hosts for E. hexagrammi. This acanthocephalan can be distinguished from three morphologically similar species, E. gadi Zoega in Müller, 1776, E. laurentianus Ronald, 1957 and E. salmonis, by the possession of the following characters: 12-16 (usually 14) rows of hook on the proboscis, a proboscis width of 170-240 μm in males and 195-270 μm in females, a hook root length of 35-45 μm in males and 40-50 μm in females, and linearly or almost linearly arranged cement glands in males.
    Systematic Parasitology 09/2011; 80(1):35-40. · 1.26 Impact Factor
  • Hirotaka Katahira, Kouki Mizuno, Kazuya Nagasawa
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    ABSTRACT: 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 March 2009. The factors associated with the nematode intensity were also assessed by applying generalized additive models (GAM). Heliconema longissimum exhibited nearly 100% prevalence in both areas, but its intensity differed. The heavier infection in the cove eels indicates that H. longissimum is mainly distributed in the cove, which supports the past speculation for this nematode as a brackish-water parasite. The intensity also increased with the body size of eels. This tendency suggests that the eels inhabiting the cove consume, as they grow, a greater quantity of crustaceans that presumably serve as the nematode's intermediate hosts.
    Journal of Parasitology 06/2011; 97(6):994-8. · 1.32 Impact Factor
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    ABSTRACT: As many as 1,079 specimens of the branchiuran parasite Argulus japonicus Thiele, 1900 were found on the body surface of an Amur catfish Silurus asotus in Ehime Prefecture, Shikoku, central Japan. This finding constitutes the first documented record of A. japonicus from Shikoku. Silurus asotus is a new host. The sex ratio in the sample of A. japonicus was male-biased. Among various skin regions of the fish, both the lateral area of the anterior trunk and the dorsal area of the head were most abundantly infected, and the dermal tissues in these areas were exposed externally.
    01/2010;
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    ABSTRACT: Six hundred fifteen specimens of the cystidicolid nematode Salvelinema salmonicola (Ishii, 1916) were found in the swimbladder of a sockeye salmon Oncorhynchus nerka from Lake Toya, central Hokkaido, northern Japan. The stomach of this fish contained many, benthic gammaridean amphipods Jesogammarus jesoensis, which are most likely to serve as an intermediate host for S. salmonicola in the lake. While sockeye salmon are known to exclusively prey on small fish when the zooplankton biomass remains low in this locality, the present findings of S. salmonicola and J. jesoensis indicate that these salmon feed on benthic amphipods as well and get infected with the nematode.