著者

笠井 久会 荒井 克俊

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.70, no.2, pp.113-118, 2020-12-23

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The student handbook (Gakubu-Annai or Gakusei-Binran) is distributed to all the freshman students in Hokkaido University at the first guidance class. This book provides various instructions on daily student life as well as general information for academic programs given by different undergraduate schools or faculties. In the chapter related to the Department of Fishing Science (DFS), Faculty of Fisheries, precondition sentence, female students are not suitable for DFS or similar sentences, was continuously found in the student handbook from 1980 to 1992. Such a statement presumably gave negative influence on female students, when choosing the undergraduate program to study. Although two female students graduated the department of Food Science and Technology, Faculty of Fisheries, for the first time in 1953, female students who graduated DFS first appeared in 1978. They decided to study fishing science despite the influence of the statement. Here, we examined the relationship between descriptions in the student handbook and percentages of female students in undergraduate and graduate programs of the Faculty of Fisheries Sciences, Hokkaido University.

著者

井黒 浩輔 今村 央

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.73, no.1, pp.27-32, 2023-08-04

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Three specimens of the birdbeak burrfish Cyclichthys orbicularis (Bloch, 1785) and a single specimen of the pelagic porcupine fish Diodon eydouxii Brissout de Barneville, 1846, collected from Usujiri, Hakodate, Hokkaido, Japan represent the first records from Hokkaido and northernmost records of both species. Together with Chilomycterus reticulatus (Linnaeus, 1758) and Diodon holocanthus (Linnaeus, 1758), diodontid species reported from Hokkaido. A single specimen, previously reported as a young individual of Ch. reticulatus, was reidentified as Cy. orbicularis.

著者

IMAMURA Hisashi YABE Mamoru

出版者

北海道大学大学院水産科学研究科

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.53, no.3, pp.107-128, 2002-12

著者

今井 圭理 渡邉 豊

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.65, no.2, pp.111-116, 2015-08-20

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Massive radioactive cesium was released to the North Pacific Ocean by the accident of the TEPCO Fukushima Dai-ichi Nuclear Power Plant from March 2011. Using the T/S "Oshoro-Maru" cruise, we started monitoring the concentration of radioactive cesium radioactive cesium(134Cs and 137Cs) in the North Pacific surface water from May 2011. Until December 2014, the samplings were carried out at 394 stations in the North Pacific Ocean including the Japan Sea and the Bering Sea. High concentration of radioactive cesium has been observed off Tohoku in 2011, and afterwards spread through the eastern side of the North Pacific by the Kuroshio Extension. In the most region, the radioactive cesium in the surface water reduced by less than the detection limit by the end of 2012. In order to clarify the spatiotemporal change of radioactive cesium in the ocean in future, the continuous monitoring by using the T/S "Oshoro-Maru" cruise be useful.

著者

三谷 曜子 岡崎 宏美 関口 圭子 宮下 和士

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.61, no.2-3, pp.65-74, 2011-12-26

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Killer whales Orcinus orca are cosmopolitan in distribution, but study sites are restricted to small geographic areas, primarily shore-based and boat-based studies focusing on nearshore areas. To contribute understanding about the biology of killer whales in pelagic areas, we created photographic identification catalogue of killer whales sighted during T/S Oshoro-maru cruise to the northern North Pacific, Bering Sea and Chukchi Sea in 2003, 2005-2009. For 6 years, 37 groups were found, containing 182 whales, and 29 individuals were identified from left side photos of dorsal fin. No individual was re-sighted within-year, nor between-year. And no matches were found between killer whales observed in Alaska, Russian far east seas, Kushiro and Shiretoko, Japan. Our result can serve as background information for the future study of pelagic killer whales.

著者

Hanamiya Yurika Murase Hiroto Matsuno Kohei Yamaguchi Atsushi

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.70, no.1, pp.77-89, 2020-08-24

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This study conducted diel vertical migration and active migration flux estimation of macrozooplanktonic amphipods and euphausiids at 0-250 m water column of the three stations in the western North Pacific during summer. For amphipods, 25 species belonging to 17 genera were identified. Their standing stock was 60-574 ind. m−2 during the daytime and 35-5,228 ind. m−2 at night-time. For euphausiids, 19 species belonging to 7 genera were identified. The standing stock of euphausiids was 80-382 ind. m−2 and 286-2,156 ind. m−2 during the day and at night, respectively. Feeding impacts during the night were estimated to be 0.19-11.76 mg C m−2 day−1 (amphipods) and 5.12-16.42 mg C m−2 day−1 (euphausiids). Respiration during the daytime accounted for 0.08-6.38 mg C m−2 day−1 (amphipods) and 2.33-7.70 mg C m−2 day−1 (euphausiids). The feeding impact and respiratory flux by active migration of macrozooplankton taxa were estimated as 8.34-28.18 mg C m−2 day−1 and 3.15-14.08 mg C m−2 day−1, respectively. These values corresponded to 3.7-12.4% of primary production (feeding impact) and 2.4-10.7% of sinking passive flux from the euphotic zone (respiratory flux). Thus, this study emphasizes the importance of active flux by macrozooplankton for vertical material flux in the western North Pacific.

著者

東 大聖 宗原 弘幸

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.71, no.2, pp.51-67, 2021-12-23

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We conducted SCUBA-based surveys of the larval and juvenile fish fauna in reef and seaweed areas in the inshore region of Usujiri, Hakodate, along the Pacific coast of southern Hokkaido, Japan, from 2019 to 2020. A total of 100 species in 10 orders and 44 families were identified based on morphological observations and DNA barcoding analyses of the cytochrome c oxidase subunit I (COI) gene. Of these species, two specimens of the labrid, Pseudolabrus sieboldi Mabuchi and Nakabo, 1997, one specimen of the cottid, Cottus hangiongensis Mori, 1930, two specimens of the blennid, Petroscirtes breviceps (Valenciennes, 1836), and one specimen of the gobiid, Pterogobius zacalles Jordan and Snyder, 1901, represent the first records of these four species in the study area. In addition, three specimens of the Stichaeid, Lumpenopsis pavlenkoi Soldatov, 1916, represent the first records captured during juvenile stages of this species, and one specimen of the pleuronectid, Lepidopsetta mochigarei (Snyder, 1911) represent the first juvenile captured in Usujiri of these species. The fish list is also added in this report.

著者

Yamaguchi Atsushi

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.71, no.1, pp.29-37, 2021-08-03

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Respiratory oxygen consumption rates (at the two temperatures of 0-50 m and 50-200 m depth strata) and day/night biomass in the top 50 m water column were determined on adult female Metridia pacifica at twelve stations in the western/ eastern subarctic Pacific and one station in the oceanic Bering Sea during summer. At each station, the respiration rates at 0-50 m depth temperatures were used to estimate ingestion rates during nighttime by assuming empirical carbon budget efficiencies, and rates at 50-200 m to estimate respiratory carbon flux during daytime. The abundance of the females in the upper 50 m at night varied between 27 and 5,422 inds. m−2 and no specimen was collected from the same layer at daytime throughout the stations. The size of the females varied regionally from 25 to 77 μg C ind.−1. As a result, diel vertical migrant biomass of the females varied greatly from one station to the next (1 and 309 mg C m−2). Weight-specific respiration rates of the females were 2.2-6.3 μl O2 mg C−1 h−1, which was a function of experiment temperatures and body mass (C) of the females. Taking into account of residence time at 0-50 m and 50-200 m in the day, daily population ingestion was estimated as 0.04-11.04 mg C m−2 day−1, which accounted for 0-2.4% of primary production at each station. Daily population respiration in the 50-200 m was calculated as 0.02-9.39 mg C m−2 day−1, which corresponds to 0-10% of the POC flux down from the euphotic zone.

著者

Abe Yoshiyuki Hildebrandt Nicole Matsuno Kohei Niehoff Barbara Yamaguchi Atsushi

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.70, no.1, pp.91-102, 2020-08-24

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We compared copepod abundance, biomass and community structure in the Atlantic sector (Fram Strait) and Pacific sector (Canada Basin) of the Arctic Ocean by using vertical stratified zooplankton samples collected from 0-1,000 m or 0-1,500 m during daytime in summer. Abundance and biomass were high at the surface layer and decreased with increasing depth in both regions. Abundance and biomass in the surface layer in the Fram Strait were 6-18 times higher than those in the Canada Basin. According to cluster analysis, the copepod communities were separated into three groups that varied vertically and included both locations. Regional differences were marked for Calanus finmarchicus, which was distributed only in the Fram Strait. In the Canada Basin, Spinocalanidae composed 56.1% of calanoid copepod abundance for the bathypelagic groups and also contributed 7.5% of abundance throughout the water column. The dominance of Spinocalanidae may reflect the oligotrophic environment in the Pacific sector of the Arctic Ocean.

著者

三宅 誠音 磯田 豊 今井 圭理 小熊 健治 澤田 光希

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.70, no.1, pp.1-11, 2020-08-24

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The shelf slope off Cape Erimo is very steep, and its slope width (L~30 km) is smaller than the internal radius deformation (λi~50 km). A simple model is used to investigate the dynamic response of Oyashio barotropic flow passing through this local steep slope area. Model results suggest that near-bottom Oyashio water cannot intrude from shelf area off Cape Erimo to Hidaka Trough, because inverse flow accompanied by the bottom trapped shelf wave is generated over the steep slope under the physical condition of L <λi. To confirm the existence of such inverse flow, hydrographic data at upstream and downstream both sides of shelf area off Cape Erimo were examined.

著者

村上 祐一 倉西 森大 CHAMSAI Sawitree 岡本 純一郎

出版者

北海道大学大学院水産科学研究科

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.62, no.3, pp.51-61, 2012-12

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我が国の漁業管理は,許可制度と漁業権制度によって組み立てられている。いずれも漁業管理当局の許可又は免許という形で漁業を営む権利が確立するが,漁業権制度は,所謂許可制度とは異なった由来と性格をもつ。漁業権制度は,沿岸地域の漁業者集団による特定の漁業を目的とした沿岸地先水域の共同使用権的性格を有している。漁業権制度の起源を歴史的に辿れば,江戸時代の幕府の沿岸漁業統治の指針とされた律令要略の所謂「磯は地先,沖は入会」に由来し,それが明治漁業法により近代法制国家の下で漁業権の法的権利として確立されたものである。その後,戦後の沿岸漁業民主化のための制度変更を経て,漁業権制度は沿岸漁業者集団による沿岸漁業の自主管理枠組みとして我が国の漁業管理制度の骨格を成してきた。戦後,沿岸漁業の稠密化への対応として我が国の外延的漁業発展過程の中で企業経営が中心の沖合,遠洋漁業が漁獲量,漁獲金額において我が国の漁業の主役となるなかで沿岸漁業の漁業権制度は我が国漁業界においてある種,自明な制度として定着してきた。しかしながら近年,沿岸漁業の外部から漁業権制度について,その閉鎖性,非効率性を批判し,漁業権制度の改革ということが議論されるようになってきた。このような議論に対して漁業協同組合を中心に強い反発が起きている。2007年2月,経済団体連合会,日本商工会議所,経済同友会,日本貿易会の経済4団体の支援を受けた日本経済調査協議会は,規制改革議論の一環として水産業の戦略的な抜本改革を求める緊急提言を行った。この提言の背景には日本の水産業の低迷(水産資源減少,漁業経営の悪化など)があり,議論は漁業の活性化のための制度改革論として主導されたものであるが,その中で漁業の活性化のための漁業資源の科学的管理(許容漁獲量による管理),漁業経営の改善(許容漁獲量の漁業者への譲渡可能な個別割当)とともに漁業制度の規制緩和策として漁業協同組合員の資格要件の緩和と漁業権の中の定置漁業権,養殖のための特定区画漁業権を漁業協同組合以外の個別経営体にも免許を認めるべきとの提言が行われている。日本経済調査協議会の緊急提言は,現在の水産資源管理に不満を有する資源研究者を含め水産関係研究者をも巻き込み大きな議論となった。特に,漁業権制度の改革提言に対して沿岸漁業者の団体であり,漁業権制度の当事者である漁業協同組合は日本経済調査協議会の緊急提言に強く反発した。日本経済調査協議会の緊急提言をめぐる議論は,政権交代や政府の規制改革会議の終了により一旦は沈静化したものの,2011年3月11日に起きた東日本大震災という未曾有の災害からの水産復興対策議論の中で養殖のための特定区画漁業権の免許資格の規制緩和論が再び浮上することとなった。

著者

泉 ひかり 萩原 聖士 玄 浩一郎 井尻 成保 足立 伸次

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.65, no.3, pp.125-130, 2015-12-20

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Removal of ribosomal RNAs(rRNA) from total RNA in eggs before preparation of a RNA library is required for the analysis of maternal mRNA using next-generarion sequencing ; this mRNA is essential for normal development. In mammals, the rRNA-depletion method is well-established and is already being used for the development of experiment kits. However, this method is not designed for other species, e.g., non-model organisms. In the current study, we attempted to remove rRNA from total RNA of Japanese eel Anguilla japonica, which is one of the most important aquaculture species in Japan. Removal was performed via hibridization-selection using mammalian probes from a commmercially available kit and/or an ordinally designed eel probe. Quantitative polymerase chain reaction(PCR) was performed to examine the depletion efficiency of 18S rRNA and 28S rRNA were comparative between each method, and >98% depletion was achieved. In addition, RNA-sequencing analysis using a next-generation sequencer and read-mapping analysis were carried out using the rRNA-depleted RNA, which was prepared using a mammalian probe, and mapping analysis revealed that rRNA reads were <1% of the total reads. These results suggest that an rRNA-depletion kit designed for a mammal can also be used for fish species.

著者

宮原 一 今村 央 石戸 芳男 仲谷 一宏

出版者

北海道大学大学院水産科学研究科 = GRADUATE SCHOOL OF FISHERIES SCIENCES, HOKKAIDO UNIVERSITY

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.53, no.3, pp.87-89, 2002-12

著者

小城 春雄 笠 康三郎

出版者

北海道大学大学院水産科学研究科

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.52, no.2, pp.71-93, 2001-09

著者

磯田 豊 荒巻 能史

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.70, no.2, pp.119-132, 2020-12-23

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Selecting the parameters to represent vertical distributions of potential temperature and carbon isotope of δ14C obtained over almost whole areas in the Japan Sea, the average age of deep circulation was calculated using vertical one dimensional multi-layered model. The model results suggest that the maximum age of 160 year appears near the depth of 2,000 m and a reasonable vertical diffusive coefficient is around 2 cm2s−1. A sinking volume transport to deep water below 1°C is estimated to be about 1.3 Sv (1 Sv = 106 m3s−1), which has the same order of magnitude as the inflow volume transport of the Tsushima Warm Current.

著者

田村 亮輔 中川 宙飛 五嶋 聖治

出版者

北海道大学大学院水産科学研究科

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.64, no.2, pp.37-44, 2014-07

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アサリRuditapes philippinarumはサハリンから日本,朝鮮半島,中国に分布し,潮間帯から水深約10mまでの砂礫泥底に生息する潜砂性の二枚貝である(松隈,2004)。日本においては古くから沿岸漁業の重要種として漁獲が行われてきたが,近年その資源は減少傾向にあり(伊藤,2002; 多賀ら,2005; 松川ら,2008),資源管理技術の確立が望まれている。適切な資源管理を行う上で本種の成長や成熟に関する情報は不可欠であるが,北海道におけるそれらの知見は本州や九州に比べて乏しく,北海道内においてもアサリ漁業の中心である道東域(中川,1994)に限られているのが現状である。北海道函館湾に面する北斗市(旧上磯町)館野地区では,殻長32mm以上の個体を対象に漁獲が行われている。しかし当該地域においては本種の産卵期についてわずかに知見があるのみで(清水ら,2006),成長に関する情報は不足している。

著者

小野 祐嗣 磯田 豊 工藤 勲 宮園 章 有田 駿

出版者

北海道大学大学院水産科学研究科

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.65, no.2, pp.47-59, 2015-08

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北海道オホーツク海側の沿岸に沿って南下する宗谷暖流は,宗谷海峡を挟む日本海とオホーツク海の水位差(圧力勾配力)によって駆動されている(青田,1975)。実際に,係留流速計・HFレーダ・海底設置型ADCP等を用いた長期流速記録と現場の水位差記録(稚内と網走の水位差)の間には高い相関があり,宗谷暖流はその水位差が極大となる夏季に流量増加,水位差がほとんどなくなる冬季にはほぼ消滅という明瞭な季節変化を示す(例えば,松山ほか,1999; Fukamachi et al.,2008; Ebuchi et al.,2009)。宗谷暖流は基本的に水位差駆動されているので順圧流が支配的であるが,成層が発達する夏季には傾圧流量の寄与が順圧流量の半分弱程度になるという見積もり報告もある(Matsuyama et al.,2006)。夏季の宗谷暖流の沖合境界表層に出現する冷水帯は,順圧流と傾圧流が相互作用した結果として理解されている。例えば,Ishizu et al. (2006)は順圧流の強い水平シアーから生じる海底エクマン収束が鉛直循環流を生成し,冷たい底層水が海面まで湧昇するという物理機構で冷水帯の形成を説明している。

著者

Sugioka Rikuto Matsuno Kohei Takahashi Keigo D. Makabe Ryosuke Takahashi Kunio T. Moteki Masato Odate Tsuneo Yamaguchi Atsushi

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.71, no.1, pp.39-50, 2021-08-03

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Various zooplankton studies have been conducted in the Indian sector of the Southern Ocean, but studies investigating spatial changes in both meso- and macro-zooplankton populations are limited. To reveal the north-south change of the mesoand macro-zooplankton community structure and the population structure of large copepods, we investigated zooplankton communities collected by the Ocean Research Institute (ORI) net along the 110°E transect in the Indian sector of the Southern Ocean during the austral summer. The zooplankton abundance and biomass were high at the stations north of 60°S and was dominated by large copepods, especially Calanoides acutus. A cluster analysis identified four zooplankton community groups. The distribution pattern of the community groups is likely to be related to the frontal system. The population structure of the dominant species of C. acutus, Calanus propinquus and Rhincalanus gigas had a similar tendency ; early copepodite stages were abundant in the northern region, while late copepodite stages dominated in the southern region. The meridional changes in the population structure are explained by different reproduction periods in each region related to sea-ice melt timing.

著者

樋口 淳也 河合 俊郎 宇治 利樹 今井 圭理

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.71, no.1, pp.21-28, 2021-08-03

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Seven specimens of fishes and three specimens of crabs were collected with drifting algae by T/S Oshoro-maru from off the Pacific coast of Tohoku region, northern Japan. In fishes, a single specimen was identified as Histrio histrio (Linnaeus, 1758), five specimens as Oplegnathus punctatus (Temminck and Schlegel, 1844) and a single specimen as Stephanolepis cirrhifer (Temminck and Schlegel, 1850). In crabs, except a single specimen of megalopa, a single specimen was identified as Guinusia dentipes (De Haan, 1835) and a single specimen as Portunus (Portunus) sanguinolentus sanguinolentus (Herbst, 1783). Because previous northernmost records of P. (P.) sanguinolentus sanguinolentus were reported from Boso Peninsula in the Pacific Ocean and Akita Prefecture in the Sea of Japan, the present specimen represents the northernmost record of the species in the Pacific Ocean.

著者

Obata Kota Kawai Toshio Takatsu Tetsuya

出版者

北海道大学大学院水産科学研究院

雑誌

北海道大学水産科学研究彙報 (ISSN:24353353)

巻号頁・発行日

vol.71, no.1, pp.15-20, 2021-08-03

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The coloration of small individuals of Nozawa’s prickleback, Stichaeus nozawae is presented for the first time, based on a specimen (112 mm SL) collected by T/S Ushio-maru from the Funka Bay, Hokkaido. The specimen has obscure bands on dorsal, anal, caudal and pectoral fins. Although specimens of comparable sizes (57.4-168 mm SL) have obscure bands on these fins, most larger specimens (252-361 mm SL) have no bands on the caudal and pectoral fins. Most descriptions or images in previous studies, including the original description, were based on large specimens (220-450 mm SL), which have no bands on these fins. Thus, bands on caudal and pectoral fins of S. nozawae tend to disappear with growth