Ichiro Takeuchi

Ehime University, Matuyama, Ehime, Japan

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Publications (49)79.47 Total impact

  • Ichiro Takeuchi
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    ABSTRACT: A new species of amphipod crustacean (Amphipoda: Phtisicidae), Paraproto mccaini n. sp. is described based on specimens collected from south of Elephant Island, the South Shetland Islands near the Antarctic Peninsula. This species was first reported as Paraproto condylata (Haswell, 1885) [sensu lato], recorded from a temperate region of Australia. P. mccaini n. sp. is distinct from P. condylata [sensu stricto] by an elongated head with pereonite 1, presence of a mid-lateral projection on pereonites 2-4, and lack of a distal round projection on the propodus of gnathopod 2. Paraproto differs from Pseudoprotomima, the most phylogenetically similar genus, in having gills on pereonites 3 and 4.
    No preview · Article · Aug 2015 · Polar Science
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    ABSTRACT: We subjected edible parts of Lateolabrax japonicus and three related species collected from western Japan in the period 2007–2012 to congener-specific concentration analysis of PCBs using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). PCBs ranged from 1 ng/g wet wt in Lateolabrax sp. A aquacultured in Ehime to 80 ng/g wet wt in L. japonicus from Hyogo (facing the Seto Inland Sea). Although eutrophication of the Seto Inland Sea is almost homogenous, high PCB concentrations were restricted to the eastern sector. In most of the fish, penta- to hepta-chlorinated congeners were dominant. The low PCB concentrations measured in aquacultured seabass from Ehime might be related to the provision of low-contaminant feeds. The Toxic Equivalent (TEQ) of dioxin-like PCBs ranged from 0.1 to 1.4 pg/g wet wt, values that are within the “safe levels for human-consumption criteria” used by the Japanese government.
    Full-text · Article · Jun 2015
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    ABSTRACT: We determined concentrations of 23 trace elements (TEs), and stable carbon and nitrogen isotope (δ(13)C and δ(15)N) signatures in barramundi (Lates calcarifer) specimens collected along the coast of Vietnam in the Northern (NCZ), Central (CCZ) and Southern (SCZ) zones in the period 2007-2010. A combination of δ(13)C and δ(15)N signatures provided insight into ontogenetic shifts in barramundi foraging choices. There were clear zone-dependent differences in Mn, As, Sr and Tl concentrations; levels of Tl were highest in the NCZ, As in the CCZ, and Mn and Sr in the SCZ. Lowest concentrations of Rb occurred in the NCZ, Bi was lowest in the CCZ, and Cd and Cs were lowest in the SCZ. δ(15)N values significantly increased with increasing Zn, Se, Sn and Cs. Concentrations of TEs in barramundi from Vietnam were below worldwide guidelines for human consumption.
    Full-text · Article · May 2014 · Marine Pollution Bulletin
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    ABSTRACT: We collected two subspecies of masu salmon: Oncorhynchus masou masou from four localities (southern Sea of Japan northward to Hokkaido) and O. masou ishikawae from upstream from Ise Bay close to a heavy industrial area. All 209 PCB congeners were analyzed using HRGC/HRMS. PCA ordination of congener concentrations divided data into three groups: (i) ssp. masou from Hokkaido, (ii) ssp. masou from the other regions and (iii) ssp. ishikawae. The highest ∑ PCB concentration (40.39ng/wet wt) was in ssp. ishikawae followed by ssp. masou from southern waters; however the TEQdioxin-like PCBs was highest in ssp. masou from southern water (1.96pg-TEQdioxin-like PCBs/g wet wt.) due to the high proportion of congener #126 in its complement (#126 has the highest toxic equivalency factor among congeners). There is likely a contamination source offshore in the southern Sea of Japan and/or along the migratory route of ssp. masou.
    No preview · Article · May 2014 · Marine Pollution Bulletin
  • Ichiro Takeuchi · Yuki Inoue
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    ABSTRACT: Orthoprotella spinigera Mori, 1996 (Crustacea: Amphipoda: Caprellidae) was collected from a coral reef at Oura Bay on the east coast of Okinawa Island, Japan. This is only the second record for O. spinigera. The type locality is the Amakusa Islands, Kyushu, ca. 700 km north of the current collection. The species may be widely distributed along the western and southern coasts of Japan. Orthoprotella spinigera appears similar to Metaprotella sandalensis Mayer, 1898, but differs in the head having a pair of apical rounded projections, lacking a triangular projection below the eye, and having longer fused pereonites 6 and 7.
    No preview · Article · Jan 2014 · Plankton and Benthos Research
  • Ichiro Takeuchi · Jacqueline Hui Chern Lim · Yuki Inoue
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    ABSTRACT: Two species of Protella Dana, 1852 (Crustacea: Amphipoda) are described in detail: P. gracilis Dana, 1853, based on type specimen collected from Balabac Strait, separating the Philippines and Borneo in the tropical Indo-Pacifi c and deposited in the Museum of Comparative Zoology, Harvard University; and P. amamiensis, new species, collected from Amami Islands, Ryukyu Archipelago, southern Japan, situated at the border of temperate and tropical regions in the northern Pacifi c. Protella amamiensis, new species, differs from P. gracilis in its 2-articulate pereopods 3 and 4, small penes, and elongated uropod 1.
    No preview · Article · Jan 2014 · The Raffles bulletin of zoology
  • Ichiro Takeuchi · Aki Oyamada
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    ABSTRACT: Caprella californica Stimpson, 1857 [sensu lato] is one of the dominant species of Caprella spp. (Crustacea: Amphipoda) along the Pacific coast of Mexico to Canada and Japan to Hong Kong, China, and recently widely reported from the Australian coasts. Detailed morphological comparison of C. californica [sensu lato] collected from California and the Uwa Sea, Japan, revealed several diagnostic differences, including: (1) the body somites of the former are more slender than those of the latter; (2) in the male of the former, head possesses an anteriorly curved dorsal projection, while in the latter, head possesses a straight, forward-pointing dorsal projection; (3) in the former, pereonite 5 is longer than pereonites 3 and 4, while in the latter, pereonite 5 is the same length as pereonite 3; (4) in the male of the former, propodus of gnathopod 2 has a small apical rectangular projection, while in the latter, the corresponding margin has a large round projection; and (5) in the former, pereopod 7 is slender with the merus and propodus subequal, while pereopod 7 in the latter is robust with the merus shorter than propodus. These differences are indications of species level differences. Thus, we propose Caprella scauroides Mayer, 1903 to a species level for the Japanese C. californica [sensu lato]. A detailed description with illustrations of C. californica [sensu stricto] and C. scauroides is provided.
    No preview · Article · Jun 2013 · Helgoland Marine Research
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    ABSTRACT: By field sampling and laboratory experiments we compared the mechanisms by which polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are biomagnified. We measured PBDEs and PCBs, together with stable carbon and nitrogen isotopes as an index of trophic level, in low-trophic-level organisms collected from a coastal area in Tokyo Bay. PBDEs were biomagnified to a lesser degree than PCBs. The more hydrophobic congeners of each were biomagnified more. However, the depletion of BDE congeners BDE99 and BDE153 from fish was suggested. To study congener-specific biotransformation of halogenated compounds, we conducted an in vitro experiment using hepatic microsomes of two species of fish and five BDE congeners (BDE47, 99, 100, 153, and 154) and five CB congeners with the same substitution positions as the PBDEs. BDE99 and 153 were partially debrominated, but BDE47 and 154 were not debrominated. This congener-specific debromination is consistent with the field results. Both in vitro and field results suggested selective debromination at the meta position. The CB congeners were not transformed in vitro. This result is also consistent with the field results, that PCBs were more biomagnified than PBDEs. We conclude that metabolizability is an important factor in the biomagnification of chemicals, but other factors must be responsible for the lower biomagnification of PBDEs in natural ecosystems.
    No preview · Article · Feb 2013 · Science of The Total Environment
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    Jacqueline Hui · Ichiro Takeuchi · Azman bin Abdul Rahim
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    ABSTRACT: Microtripus tinggiensis, a new genus and species (Amphipoda: Caprellidea: Phtisicidae), was discovered in the interstitial benthos from Pulau Tinggi, an island in the East Johor Islands Archipelago (EJIA). Microtripus tinggiensis is distinct in its reduced pereopods 3–5 (1-articulate pereopods 3, 4 and 3-articulate pereopod 5). The new genus Microtripus most closely resembles Perotripus Dougherty & Steinberg, 1953 in its elongated body segments, shorter antennae 1 and 2 and gills on pereonites 2–4 but differs from the latter by its 3-articulate flagellum of antenna 1 and 1-articulate, vestigial pereopod 3.
    Full-text · Article · May 2012 · Proceedings of the Biological Society of Washington
  • Jacqueline Hui Chern Lim · Ichiro Takeuchi
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    ABSTRACT: Metaprotella sandalensis has been widely described from tropical to subtropical regions of the Indo-west Pacific by several authors. However, the exact characteristics of the species are still unclear. The present study provides detailed descriptions of Metaprotella sandalensis Mayer, 1898 (Crustacea: Amphipoda) based on newly collected specimens from Lifou Island, New Caledonia, the type locality. The genetic diagnosis of Metaprotella was also revised. The following species characteristics for Metaprotella sandalensis are indicated: 1) suture between head and pereonite 1 is vestigial; 2) antenna 1, 0.6 to 0.8x body length; 3) peduncle article 3 longer than article 2 in antenna 1; and 4) pereonite 4 longest among all body somites. These characteristics indicate that the distribution of Metaprotella sandalensis is more narrow within the tropical Indo-west Pacific than previously reported.
    No preview · Article · Feb 2012 · The Raffles bulletin of zoology
  • N.P.C. Tu · N.N. Ha · H. Matsuo · B.C. Tuyen · S. Tanabe · I. Takeuchi
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    ABSTRACT: Problem statement: Ba Ria Vung Tau (BRVT), a Vietnamese province with one of the fastest growing economies in the country, faces significant environmental challenges, including increased contamination of rivers and estuaries with urban and industrial wastes. Approach: Concentrations of 23 trace elements and stable isotope ratios (δ 13C and δ 15N) were analyzed in suspended particulate matter, one species of peanut worm, one species of octopus, six species of crustaceans and 13 species of fish collected from an integrated shrimp mangrove farm in the BRVT. Results: Concentrations of Cu, Zn, Se, Mo, Ag, Cd, Sb and Bi in octopus, Mn, Sr and Ba in crustaceans and Hg in fish were the highest among organisms analyzed. Using δ 15N values to identify trophic positions, we found that Zn, Se and Hg biomagnified through the food web. The slope for Hg (0.048) was remarkably lower than those reported for other aquatic food webs. In contrast, the concentrations of most trace elements followed reverse trends (i.e., decreasing concentrations with increasing trophic level). Trace element concentrations we measured in organisms were within safe levels for human consumption according to criteria established by the Ministry of Agriculture, Fisheries and Food (MAFF) in the UK. However, concentrations of Cu in black tiger shrimps and octopus and Zn in Commerson's glassy fish were higher than the MAFF guidelines. Conclusion: The results of this study highlight the usefulness of δ 13C and δ 15N as a tool not only for elucidating the trophic position of biota, but also for tracing contaminants within food webs.
    No preview · Article · Jan 2012 · American journal of environmental sciences
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    ABSTRACT: This study measured concentrations of 21 trace elements in whole soft tissue of the blood cockle Anadara spp., which is a common food for local people, collected along the coast of Vietnam. Results showed that concentrations of As, Sr, Mo, Sn, and Pb in cockles collected from Khanh Hoa Province in the Central Coastal Zone (CCZ) had higher values than those from the other regions, while cockles collected from the Mekong River Delta (MRD) showed the highest concentrations of Hg. Regional differences in trace element concentrations of the cockle may be due to differences in human activities, i.e., shipyards in the CCZ and agriculture in the MRD. Trace element concentrations measured in the soft tissues of blood cockles investigated here were within safe levels for human consumption following criteria by the European Commission (EC) and the United States Food and Drug Agency, but several specimens had Cd levels exceeding the EC guidelines of 1 μg/g wet weight. The estimated target hazard quotients for trace elements via consuming bivalves were <1, indicating that the cumulative noncarcinogenic risk was completely insignificant. However, the estimated target cancer risk values by assumed inorganic As concentrations seem to implicate consumption of these cockles as posing potential human health concerns.
    Full-text · Article · Nov 2011 · Fisheries Science
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    ABSTRACT: We performed stable carbon and nitrogen-guided analyses of biomagnification profiles of arsenic (As) species, including total As, lipid-soluble As, eight water-soluble As compounds (arsenobetaine (AB), arsenocholine (AC), tetramethylarsonium ion (TETRA), trimethylarsine oxide (TMAO), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenate (As[V]), and arsenite (As[III])), and non-extracted As in a tropical mangrove ecosystem in the Ba Ria Vung Tau, South Vietnam. Arsenobetaine was the predominant As species (65-96% of water-soluble As). Simple linear regression slopes of log-transformed concentrations of total As, As fractions or individual As compounds on stable nitrogen isotopic ratio (δ15N) values are regarded as indices of biomagnification. In this ecosystem, lipid-soluble As (slope, 0.130) and AB (slope, 0.108) were significantly biomagnified through the food web; total As and other water-soluble As compounds were not. To our knowledge, this is one of the first reports on biomagnification profiles of As compounds from a tropical mangrove ecosystem.
    Full-text · Article · Apr 2011 · Marine Pollution Bulletin
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    ABSTRACT: The dominant coastal bivalve in Vietnam, hard clams Meretrix spp., collected from the South Key Economic Zone (SKEZ), the Mekong River Delta, and the Central Coastal Zone (CCZ) were analyzed for 21 trace elements. Comparison of the results from the three regions indicated that levels of most of the trace elements, especially As, Mo, Sn, and Pb, were highest in the samples collected from the CCZ, whereas most of the trace elements were found to be present at relatively low levels in samples from the SKEZ. The high concentrations of these trace elements in the CCZ, a sparsely populated region with less human activity than the other two regions, were believed to have originated from industrial waste produced in a shipyard. Although the trace element concentrations in the bivalves were within safe levels for human-consumption criteria reported by the United State Food and Drug Administration and the European Commission, estimation of cancer risk based on As concentration indicates that the hard clams from the CCZ pose a high risk to consumers. Thus, the industrial waste produced in the less densely populated region might increase the health risk to consumers via the contamination of bivalves commonly used as food. KeywordsHealth risk- Meretrix -Shipyard waste-Trace element-Vietnam
    Full-text · Article · Jul 2010 · Fisheries Science
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    ABSTRACT: Organisms collected from a coastal ecosystem in Japan were analyzed for concentrations of 205 polychlorinated biphenyls (PCBs) congeners; analyses were guided by delta(13)C and delta(15)N measurements. The regression slopes of log PCB concentration on delta(15)N value are regarded as indices of biomagnification in food webs. The slope (wet weight basis) of SigmaPCBs was +0.104; the slope (lipid weight basis) was close to zero. Lipid content increased from 0.06% in a primary producer to 8.32% in the highest trophic level consumer. Hence, biomagnification of SigmaPCBs (wet weight basis) can be attributed to increase of lipid content through the food web. For most of the congeners, the slopes (wet weight basis) exceeded those (lipid weight basis) by ca. 0.10. Slopes increased with increasing PCB chlorination levels between chlorine numbers 1-6; slopes decreased at higher chlorination levels. This decrease is likely caused by a decrease in membrane permeability with increasing molecular weight.
    Preview · Article · Sep 2009 · Marine Pollution Bulletin
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    ABSTRACT: Bivalves, crabs, fishes, seawater, and sediment collected from the inner part of Tokyo Bay, Japan, were measured for 20 polybrominated diphenyl ether (PBDE) and 5 polychlorinated biphenyl (PCB) congeners. To determine the trophic levels of the organisms, carbon and nitrogen stable isotope ratios (delta(13)C and delta(15)N) were also measured. Bioconcentration factors of PBDE and PCB congeners increased as the octanol-water partition coefficient (K(ow)) rose to log K(ow)=7, above which they decreased again. Biomagnification of PCBs and several PBDE congeners (BDE47, 99, 100, 153 and 154) up the trophic ladder was confirmed by a positive correlation between their concentrations and delta(15)N. Other PBDE congeners showed a negative or no correlation, suggesting their biotransformation through metabolism. The more hydrophobic congeners of both PBDEs (Br=2-6) and PCBs (Cl=6-9) were biomagnified more. It thus appears that PBDEs are less biomagnified than PCBs.
    No preview · Article · May 2009 · Marine Pollution Bulletin
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    ABSTRACT: Biomagnification profiles of polycyclic aromatic hydrocarbons (PAHs), alkylphenols, and polychlorinated biphenyls (PCBs) from the innermost part of Tokyo Bay, Japan were analyzed using stable carbon (delta(13)C) and nitrogen (delta(15)N) isotope ratios as guides to trophic web structure. delta(15)N analysis indicated that all species of mollusks tested were primary consumers, while decapods and fish were secondary consumers. Higher concentrations of PCBs occurred in decapods and fish than in mollusks. In contrast, concentrations of PAHs and alkylphenols were lower in decapods and fish than in mollusks. Unlike PCBs, whose concentrations largely increased with increasing delta(15)N (i.e. increasing trophic level), all PAHs and alkylphenols analyzed followed a reverse trend. Molecular weights of PAHs are lower than those of PCBs, therefore low membrane permeability caused by large molecular size is an unlikely factor in the "biodilution" of PAHs. Organisms at higher trophic levels may rapidly metabolize PAHs or they may assimilate less of them.
    No preview · Article · Apr 2009 · Marine Pollution Bulletin
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    ABSTRACT: In order to estimate the nitrogen loading from fish aquaculture facilities, we studied the nitrogen and carbon stable isotope ratios (δ15N and δ13C, respectively) in the brown macroalga Sargassum piluliferum and small amphipod crustaceans Caprella spp., both of which are lower trophic level biota found at fish and pearl oyster aquaculture facilities situated along the eastern coast of the Uwa Sea, Japan. This coastal region is one of the least populated areas along the Japanese coast. The mean concentrations of chlorophyll a, dissolved inorganic nitrogen, dissolved inorganic phosphate, and dissolved silicate-Si were 1.5- to 2-fold higher in samples from the fish aquaculture facilities than in those from the pearl oyster aquaculture facilities, indicating that the fish aquaculture facilities were associated with nitrogen loading. The δ15N abundance level in S. piluliferum collected from the fish aquaculture facilities was significantly higher (1.3‰) than that in macroalga collected at the pearl oyster aquaculture facilities, whereas that in Caprella spp., primary consumers, was only slightly higher (0.3‰). The feeding style of Caprella spp., which depends on suspended particulate organic matter and attached microalgae, is considered to the primary causal factor for the lack of a significant difference in δ15N abundance level between the two types of aquaculture facilities. Based on these results, we conclude that S. piluliferum found in close proximity of aquaculture facilities is a suitable organism for monitoring nitrogen loading from fish aquaculture facilities, through the analysis of δ15N.
    No preview · Article · Jan 2009 · Fisheries Science
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    ABSTRACT: Four years after the construction of an artificial tidal flat in Osaka Bay, Japan, the food web structure was analyzed using stable isotope ratios of nitrogen and carbon. The nitrogen stable isotope ratios (δ15N) ranged from 8.8±0.3‰ in Chondrus giganteus f. flabellatus (macroalga) to 15.2‰ in Repomucenus beniteguri (fish), whereas the carbon stable isotope ratios (δ13C) ranged from -18.6±0.2‰ in POM (particulate organic matter) to -10.5±1.1‰ in Ulva sp. (macroalga). The food web structure of the artificial tidal flat was estimated to be composed of three trophic levels. Moreover, it was thought that fishes inhabiting this ecosystem are dependent on POM and macroalgae (and/or benthic microalgae) for their carbon source, whereas crustaceans and mollusks are likely to be dependent on macroalgae (and/or benthic microalgae), not on POM. These results indicate that the food web structure of the artificial tidal flat resembles those of natural estuaries along the Japanese coasts. A temporal analysis of the food web structure of an artificial tidal flat and a comparison of such a structure to that of closely situated natural tidal flats using stable isotope analysis will contribute significantly to the evaluation of the structure and function of artificial tidal flats.
    No preview · Article · Jan 2009 · Journal of Japan Society on Water Environment
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    ABSTRACT: The goal of the present study was to examine the specific bioaccumulation of 22 trace elements in muscle, exoskeleton and hepatopancreas of black tiger shrimp Penaeus monodon from the Mekong River Delta (MRD), and the South Key Economic Zone (SKEZ), South Vietnam. The general tendency in most trace element concentrations among different tissues were hepatopancreas>exoskeleton>muscle. Comparisons of trace element levels in tissues between the two regions showed that concentrations of Se in muscle and As in all three tissues were higher in SKEZ; whereas in MRD, the higher concentrations of most elements such as Mn, Cu, Cd, Ba, Hg, were observed in tissues. These geographical variations in trace element levels may reflect the differences in human activities between the two regions of South Vietnam. The target hazard quotient (THQ) values for trace elements (<1) indicate that local residents are not exposed to potential health risks via the consumption of shrimp.
    No preview · Article · Dec 2008 · Marine Pollution Bulletin

Publication Stats

705 Citations
79.47 Total Impact Points


  • 2002-2015
    • Ehime University
      • • Faculty of Agriculture
      • • Center for Marine Environmental Studies (CMES)
      Matuyama, Ehime, Japan
  • 2006
    • Federal Technological University of Paraná - Brazil
      Curityba, Paraná, Brazil
  • 2001-2002
    • The University of Tokyo
      • Center for Operation
      Tōkyō, Japan
  • 2000-2002
    • Universidad de Sevilla
      • Facultad De Biología
      Hispalis, Andalusia, Spain