Faculty Profiles - AZUMA Takafumi

Papers - AZUMA Takafumi

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Kobari T., Manako Y., Hara A., Yamanoue K., Azuma T., Fukuda R., Wang Y.C., Kodama M., Kume G. . Community structure of fish larvae associated with advections of the Kuroshio and its neighboring waters . Progress in Oceanography231 2025.2

Language：Japanese Publisher：Progress in Oceanography

The Kuroshio has been long thought to be disadvantageous as nursery grounds for larval fishes due to the low plankton standing stocks under the oligotrophic conditions. Despite of the potential risk for survival and growth, early life stages of various fishes appear abundantly in the Kuroshio and its neighboring waters. Here, we report what kind of taxonomic groups establish community structure of larval fishes in the Continental shelf waters (CW) and the Kuroshio (KW). 16 orders and 78 families were classified in the present study. Mesopelagic fishes more abundantly appeared in the KW than in the CW, while larval fish abundance was not different between the two areas. Multivariate analysis demonstrated the regional difference of the taxonomic compositions, represented by Callionymidae, Bothidae, Labridae and Bregmacerotidae for the CW and Gonostomatidae, Myctophidae and Notosudidae for the KW. Abundance of fish larvae to ambient salinity exhibited significantly positive correlations for Gonostomatidae, Sigmops gracilis and Myctophum orientale predominated in the KW and negative correlations for Labridae appeared abundantly in the CW. These results suggest that mixture of advected specimens from the coastal and Kuroshio waters also contribute to larval fish community with high biodiversity and comparable abundance between the Kuroshio and its neighboring waters.

DOI： 10.1016/j.pocean.2024.103386

Scopus

Kume G., Oba H., Kodama M., Shigemura T., Shiozaki K., Ichinomiya M., Komorita T., Azuma T., Kobari T. . Growth, mortality, and predatory impact on mesozooplankton of chub mackerel Scomber japonicus larvae in an upwelling system, southern Japan . Continental Shelf Research285 2025.2

Language：Japanese Publisher：Continental Shelf Research

In the northern Satsunan area, southern Japan, upwellings generated by the intrusion of the Kuroshio branch current into Kagoshima Bay are observed at the bay's mouth once every two weeks in winter and spring, and the resulting nutrient supply promotes phytoplankton blooms. Currently, this is a key spawning and nursery habitat for chub mackerel Scomber japonicus in Japan. This study examined how water temperature and prey density influenced the growth, mortality, and predatory effects of S. japonicus larvae in the northern Satsunan area. Recent growth (measured as the average width of the last three otolith increments) of S. japonicus larvae was positively correlated with water temperature but not with prey density, indicating that prey abundance was adequate for larvae and that water temperature controlled their growth rate in the study area. The instantaneous daily mortality rate of S. japonicus larvae was 0.322 in 2021 and 0.252 in 2022 (equivalent to 27.5% mortality d−1 in 2021 and 22.3% in 2022). The food requirements of S. japonicus larvae and mesozooplankton production were 0.00427 ± 0.00334 and 6.37 ± 3.04 mg DW m−3 d−1, respectively. S. japonicus larvae had no significant predatory impact on mesozooplankton (0.0869 ± 0.0796%). The present study suggests that none of the plankton feeders have a significant top-down regulating effect on mesozooplankton biomass in the northern Satsunan area, which provides a good food environment for S. japonicus larvae.

DOI： 10.1016/j.csr.2024.105399

Scopus

Kodama M., Mukaida Y., Hosoki T.K., Makino F., Azuma T. . A new species of the genus Podoceropsis Boeck, 1861 (Crustacea: Amphipoda: Photidae) from Kagoshima Bay, Japan . Plankton and Benthos Research19 ( 3 ) 141 - 152 2024

Language：Japanese Publisher：Plankton and Benthos Research

A new species of photid amphipod, Podoceropsis nanseiae, is described from Kagoshima Bay, Japan. The present new species can be distinguished from all the congeners in having clusters of robust setae on the male gnathopod 2 basis. This species resembles Gammaropsis laevipalmata Ren, 1992, however can be distinguished from G. laevipalmata by the presence of small accessory flagellum in antenna 1, the size of eyes, the shape of palmer margin of male gnathopod 2, and the clusters of robust setae on the male gnathopod 2 basis. The closely related species G. laevipalmata should be transferred to the genus Podoceropsis. Additionally, a partial DNA sequence of the mitochondrial cytochrome c oxidase subunit I (COI) was determined from the type specimens of P. nanseiae sp. nov. for future taxonomic studies.

DOI： 10.3800/pbr.19.141

Scopus

小針　統，中谷颯人，後藤慎之介，津田周平，牧野文洋，東　隆文，小森田智大，一宮睦雄，小玉将史，久米　元 . 薩南海域に来遊するブリ稚魚の餌料源 . 水産海洋研究 2023薩南海域に来遊するブリ稚魚の餌料源Reviewed

Manako Yusuke, Kobari Toru, Ichinomiya Mutsuo, Komorita Tomohiro, Habano Akimasa, Azuma Takafumi, Kume Gen . Growth activity of fish larvae appearing in the Kuroshio and its neighbouring waters . Bulletin of the Plankton Society of Japan69 ( 2 ) 93 - 101 2022.8

Language：Japanese Publisher：The Plankton Society of Japan

It has been thought that food availability for fish larvae was poor in the Kuroshio because of the low standing stocks of plankton in the oligotrophic conditions under thermal stratification throughout the year. Despite a potential risk or disadvantage for larval survival and growth, Kuroshio and its neighbouring waters are nursery grounds for the early life stages of various fishes. Here, we compared the growth activity of fish larvae among 15 taxonomic groups, including 11 families in the Kuroshio and its neighbouring waters, based on protein synthetase activity and protein contents. Protein-specific (spAARS), individual-based aminoacyl tRNA synthetase activities (iAARS), and protein contents (PRO) of fish larvae ranged from 2 to 232 nmol PPi mg protein−1 h−1, from 1 to 21 μmol PPi ind−1 d−1, and from <1 to 26 mg ind−1, respectively. spAARS, iAARS and PRO were variable among the taxonomic groups and were not classified between mesopelagic groups and the others. Compiling these measurements among all taxonomic groups, a significant negative correlation was found for spAARS to PRO. The correlation showed no significant difference between the Kuroshio and its neighbouring coastal waters, indicating that growth activities to fish larvae body mass were comparable in the Kuroshio and its neighbouring waters. Based on nonmetric multidimensional scaling on spAARS, iAARS and PRO among 15 taxonomic groups, two different groups were classified for fish larvae, represented by the high iAARS under the high PRO but low spAARS (Group 1) and the low iAARS under the low PRO but high spAARS (Group 2), representing the different life strategies for larval growth among the taxonomic groups. The present findings suggest that these biochemical indices are useful for evaluating the growth activity of fish larvae among various taxonomic groups and that food availability is not poor enough to support larval growth in the Kuroshio and its neighbouring waters.

DOI： 10.24763/bpsj.69.2_93

Scopus

Isobe A., Azuma T., Cordova M.R., Cózar A., Galgani F., Hagita R., Kanhai L.D., Imai K., Iwasaki S., Kako S., Kozlovskii N., Lusher A.L., Mason S.A., Michida Y., Mituhasi T., Morii Y., Mukai T., Popova A., Shimizu K., Tokai T., Uchida K., Yagi M., Zhang W. . A multilevel dataset of microplastic abundance in the world’s upper ocean and the Laurentian Great Lakes . Microplastics and Nanoplastics1 ( 1 ) 2021.12

Language：Japanese Publisher：Microplastics and Nanoplastics

A total of 8218 pelagic microplastic samples from the world’s oceans were synthesized to create a dataset composed of raw, calibrated, processed, and gridded data which are made available to the public. The raw microplastic abundance data were obtained by different research projects using surface net tows or continuous seawater intake. Fibrous microplastics were removed from the calibrated dataset. Microplastic abundance which fluctuates due to vertical mixing under different oceanic conditions was standardized. An optimum interpolation method was used to create the gridded data; in total, there were 24.4 trillion pieces (8.2 × 104 ~ 57.8 × 104 tons) of microplastics in the world’s upper oceans.

DOI： 10.1186/s43591-021-00013-z

Scopus

Operation of Japanese and Taiwanese fishing boats in the north of the Sakishima Islands . 68 31 - 34 2019Operation of Japanese and Taiwanese fishing boats in the north of the Sakishima Islands

黒田真央, 内山正樹, 東隆文, 内田圭一, 東海正, 向井徹, 今井圭理, 森井康宏, 八木光晴, 清水健一清水健一, 三橋廷央 . 日本周辺沖合域における海底ごみの現状 . 日本水産工学会学術講演会学術講演論文集2019 ( 0 ) 85 - 88 2019

Abe Mihoko, Azuma Takafumi, Nakamura Hirohiko Nakamura, Kobari Toru, Honma Taiga, Kanayama Takeru, Karu Fukutaro, Yoshie Naoki, Hasegawa Daisuke, Nishina Ayako, Uchiyama Masaki . Changes in Plankton Community Structure, Standing Stocks and Productivity from Upstream to Downstream of the Kuroshio Across the Tokara Strait . Bulletin on Coastal Oceanography57 ( 1 ) 65 - 72 2019

Publisher：Coastal Oceanography Research Committee, the Oceanographic Society of Japan

Plankton community structure, standing stocks and productivity were compared between upstream and downstream of theTokara Strait based on Lagrangian oceanographic observations and sampling along the Kuroshio. Surface waters above 200mwere represented by lower temperature and salinity, and nutrients and chlorophyll a concentrations at the subsurface were higherdownstream than upstream. No significant difference was found in the zooplankton community structure, and the predominantcomponents were naked ciliates for microzooplankton and copepods for net zooplankton. Although the protein synthetase activityof the net zooplankton community was high throughout the stations, large metazoans were one cause of the increased biomass andproduction rates downstream. These results suggest that the nutrient supply and phytoplankton increased at the subsurface, andthe net zooplankton biomass and productivity increased downstream of the Tokara Strait.

DOI： 10.32142/engankaiyo.2019.8.009

YAMANAKA Yuichi, UCHIYAMA Masaki, AZUMA Takafumi, MITSUHASHI Takahisa . The Current State and Problems of the Training Ship for Education and Research of Fisheries Science . Journal of Fisheries Engineering54 ( 1 ) 31 - 34 2017

Publisher：The Japanese Society of Fisheries Engineering

Training ships of Fisheries College were established to train ship's officers. These were based onthe law on University establishment standards. Recent marine science diversifies, and the purpose of atraining ship can't be called only the purpose which trains a sailor. For example, recent fishery isrequired not only to capture but also scientifically analyze and manage resources efficiently. Furthermore,the facilities which can deal with a marine environmental problem are necessary. The new practice shipneeds the latest research equipment and a structure that can use them effectively.　　Kagoshima University training ship Kagoshima-Maru is based on the 'Basic Act on Ocean Policy'which came into effect in 2007 and was built by aggregating the requirements of the latest equipmentand hull structure. In this paper, the concept of Kagoshima-Maru construction and the problems whichbecame obvious later are described.

DOI： 10.18903/fisheng.54.1_31

藤枝繁，東政能，幅野明正，東隆文，有田洋一，牧野文洋 . 北太平洋で漁獲されたマグロ類によるプラスチックの誤食 . 漂流物学会誌12 47 - 48 2014北太平洋で漁獲されたマグロ類によるプラスチックの誤食

内山正樹，善福忍，東隆文，有田洋一，牧野文洋，武田篤史，那須佳奈子 . かごしま丸における発電機関使用台数と燃料消費量の検討 . 鹿児島大学水産学部紀要第63巻63 9 - 16 2014かごしま丸における発電機関使用台数と燃料消費量の検討

有田洋一, 江幡恵吾, 不破茂, 三井健二郎, 東政能, 幅野明正, 東隆文, 牧野文洋 . ヒラツメガ二の混獲防除を目指したグランドロープの改造実験 . 日本水産工学会学術講演会学術講演論文集24 121 - 122 2012ヒラツメガ二の混獲防除を目指したグランドロープの改造実験

東政能，内山正樹，幅野明正，東隆文，福田隆二，有田洋一，牧野文洋 . The Oceanographic Conditions along 134°E from 12°N to 30°N in September, 2003 and 2009 . 鹿児島大学水産学部紀要59 1 - 9 2010.10The Oceanographic Conditions along 134°E from 12°N to 30°N in September, 2003 and 2009

Shigeru Fujieda,Masaki Uchiyama,Takafumi Azuma,Ryuji Fukuda,Youichi Arita . Ingestion Case of Plastics by Black Marlin Makaira indica and Lancetfish Alepisaurus ferox Caught in the East Indian Ocean . 鹿児島大学水産学部紀要57 47 - 48 2008.12Ingestion Case of Plastics by Black Marlin Makaira indica and Lancetfish Alepisaurus ferox Caught in the East Indian Ocean

藤枝, 繁, 内山, 正樹, 東, 隆文, 福田, 隆二, 有田, 洋一 . 東インド洋において漁獲されたシロカワカジキとミズウオによるプラスチックの誤食 . 鹿児島大学水産学部紀要57 47 - 48 2008東インド洋において漁獲されたシロカワカジキとミズウオによるプラスチックの誤食

福田隆二，益満侃，内山正樹，東隆文，有田洋一，吉永圭輔 . 2006年かごしま丸遠洋調査実習における海洋調査報告 . 鹿児島大学水産学部紀要55 87 - 89 2006.122006年かごしま丸遠洋調査実習における海洋調査報告

東隆文，福田隆二，益満侃，内山正樹，小針統，吉永圭輔 . 2005年かごしま丸遠洋調査実習航海における海洋調査報告 . 鹿児島大学水産学部紀要54 77 - 85 2005.122005年かごしま丸遠洋調査実習航海における海洋調査報告

吉永圭輔，益満侃，日高正康，内山正樹，東隆文，福田隆二 . 海面高度偏差図を使ったマグロ漁場探索への基礎的研究 . 鹿児島大学水産学部紀要53 1 - 5 2004.12海面高度偏差図を使ったマグロ漁場探索への基礎的研究

NORO Tadahide,SHIMADA Kiyoshi,HIGASHI Masataka,HABANO Akimasa,AZUMA Takafumi,INOUE Akio,NEDACHI Munetomo . PRELIMINARY MONITORING OF COASTAL SEAWATER IN YAP ISLANDS:OCTOBER,1999 . 南太平洋海域調査研究報告 34 87 - 90 2001.3PRELIMINARY MONITORING OF COASTAL SEAWATER IN YAP ISLANDS:OCTOBER,1999

ISHIGURO Etsuji,TATSUNO Katsumi,KAWAKATSU Motoi,HIRAYAMA Shinsaku,WAHID Din Ara,KONGO Sentaro,SHIMADA Kiyoshi,HIGASHI Masataka,HABANO Akimasa,AZUMA Takafumi,KIKUKAWA Hiroyuki,MORIYAMA Masao,TAIFILEICHIG Andy,PECKALIB . STUDIES ON THE EVALUATION OF WATER DEPTH AROUND SEASHORE AND THE LAND CLASSIFICATION IN YAP ISLANDS USING SATELLITE DATA . 南太平洋海域調査研究報告 34 77 - 85 2001.3STUDIES ON THE EVALUATION OF WATER DEPTH AROUND SEASHORE AND THE LAND CLASSIFICATION IN YAP ISLANDS USING SATELLITE DATA

NEDACHI Munetomo,MAEDA Tomokazu,SHIGEYOSHI Ryoichi,INOUE Akio,SHIMADA Kiyoshi ,HIGASHI Masataka,HABANO Akimasa,AZUMA Takafumi ,HATTA Akio . GEOLOGICAL ENVIRONMENTS OF YAP ISLANDS, MICRONESIA . 南太平洋海域調査研究報告 34 69 - 76 2001.3GEOLOGICAL ENVIRONMENTS OF YAP ISLANDS, MICRONESIA

東政能，市川洋，嶋田起宣，幅野明正，東隆文 . Oceanographic Conditions in Fall of 1999 along the Section between the South of Kyusyu and the Yap Islands . 鹿児島大学水産学部紀要 49 1 - 7 2000.12Oceanographic Conditions in Fall of 1999 along the Section between the South of Kyusyu and the Yap Islands

東隆文，日高正康，幅野明正，福田隆二，東川勢二 . 薩摩半島、吹上浜西方沖の底質 . 鹿児島大学水産学部紀要47 19 - 23 1998.12薩摩半島、吹上浜西方沖の底質

HATTA Akio,SHIMADA Kiyoshi,HIGASHI Masataka,HABANO Akimasa,AZUMA Takafumi . New Data on the Daily Migration of Planktic Foraminifera near the Island of Amami-Ooshima . 鹿児島大学教育学部研究紀要 50 29 - 35 1998.12New Data on the Daily Migration of Planktic Foraminifera near the Island of Amami-Ooshima

日高正康，幅野明正，東隆文，福田隆二，東川勢二 . 薩摩半島南岸沖の底質と底層流について . 鹿児島大学水産学部紀要46 39 - 45 1997.12薩摩半島南岸沖の底質と底層流について

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Papers - AZUMA Takafumi