研究者データベース

長谷川 浩平(ハセガワ コウヘイ)
水産科学研究院 海洋生物資源科学部門 海洋計測学分野
助教

基本情報

所属

  • 水産科学研究院 海洋生物資源科学部門 海洋計測学分野

職名

  • 助教

学位

  • 工学博士(東京海洋大学)

J-Global ID

研究分野

  • 自然科学一般 / 大気水圏科学

担当教育組織

研究活動情報

論文

  • Naizheng Yan, Tohru Mukai, Kohei Hasegawa, Jun Yamamoto, Yoshiaki Fukuda
    ICES Journal of Marine Science 81 1 195 - 203 2023年12月12日 
    Abstract Measurement of target strength (TS) is important for estimating the abundance of species using fisheries acoustics. However, most researchers have only used a limited number of representative frequencies for acoustic measurements of fish without a swim bladder (bladderless fish). Here, we measured the broadband TS of three bladderless fish species, arabesque greenling (Pleurogrammus azonus), Pacific sand lance (Ammodytes personatus), and pointhead flounder (Cleisthenes pinetorum), using two broadband echosounders. TS measurements were conducted in a seawater tank over frequency ranges of 45–90 and 80–120 kHz using a tether method. Higher TS and directivity were observed at higher frequencies than at lower frequencies for pointhead flounder and arabesque greenling. However, the TS for Pacific sand lance was relatively flat over the measured frequency spectra. Additionally, the TS of pointhead flounder and Pacific sand lance could be expressed as a function of body length and the TS of arabesque greenling could be expressed as a function of body length and frequency, which could be used in fish species discriminations and size estimations.
  • 長谷川浩平, 閻乃筝, 向井徹
    Journal of Marine Science and Technology 29 2 135 - 145 2021年05月 [査読有り][通常論文]
     
    Measurements of the broadband acoustic backscattering from fish should improve acoustic discrimination between species. The pulse compression processing of broadband systems can be used tomeasure acoustic backscattering with high range resolution and improve signal-to-noise ratio. This may increase opportunities for in situ target strength (TS) measurements, the preferredmethod of collecting TS data. To evaluate the availability of TS spectra for acoustic discrimination, three Simrad EK80 wideband transceivers and split-beam transducers of 70, 120, and 200 kHz were used to collect in situ frequency responses of TS from age-0 juvenile walleye pollock and pointhead flounder, a swim-bladderless flat-fish, distributed in and around Funka Bay, Hokkaido, Japan. The single echoes were extracted frombackscattering data, and the TS spectra of the two species were obtained. However, processing of the broadband acoustic data is under discussion. To ensure the reliability of our data, the TS spectra of standard targets were also calculated. The measured TS spectra of the standard targets were close to the theoretical TS spectra. The individual TS spectra of two species included complex frequency response; however, the mean TS spectrum was relatively stable. The different characteristics of the frequency responses observed for the two species were in good agreement with reported observations. The results available for the acoustic discrimination were similar to the multi-frequencymethod, which uses two or more single frequencies. The rawTS spectra should aid in not only discriminating between species but also estimating the size of the fish.
  • 閻乃筝, 向井徹, 山本潤, 長谷川浩平
    Fisheries Research 224 105434 - 105434 2020年04月 [査読有り][通常論文]
  • 澤田 浩一, 松裏 知彦, 向井 徹, 福田 美亮, 長谷川 浩平, 安部 幸樹, 佐々木 系, 山田 雄一郎
    日本水産学会誌 84 5 947 - 947 公益社団法人 日本水産学会 2018年
  • Kouichi Sawada, Tomohiko Matsuura, Kohei Hasegawa, Tohru Mukai, Matt Stone, Kei Sasaki, Hideki Nikaido
    2018 OCEANS - MTS/IEEE KOBE TECHNO-OCEANS (OTO) 2018年 
    The density of zooplankton within bays and in inshore areas is an important environmental parameter for determining the optimal release timing of juvenile salmon (Oncorhynchus keta) from hatchery stations. This is because the juveniles remain in these areas for 1 month, during which time they feed upon zooplankton before they begin their journey to the ocean. We monitored zooplankton, water temperature and salinity from 2013 to 2017 in Yamada Bay, Iwate Prefecture, Japan, using a multi-frequency acoustic profiler collocated with temperature-salinity sensors and a depth sensor. Our observations revealed that the large zooplankton preferred by juvenile salmon are transported into the bay by the Oyashio Current. Therefore, it is important to determine the timing of this transportation. We developed an online profiler to record these events at a hatchery station in Yamada Bay.
  • 内田圭一, 小川大道, 長谷川浩平, 宮本佳則, 野呂英樹, 和田由香, 秋山清二
    日本水産学会誌 84 1 14 - 22 2018年 [査読有り][通常論文]
     
    As the resource management of bluefin tuna Thunnus orientalis is becoming increasingly important, a new technology for set-net fisheries to separate young bluefin tuna from other catches is needed. If behavioral diŠerences in a set net between bluefin tuna and other species could be detected, it would help to develop such new technology. In this study, we used an ultrasonic telemetry system to study the behavior of young bluefin tuna and yellowtail Seriola quinqueradiata in a set net. The results showed that bluefin tuna swim back and forth between the second bag net and the first bag net, while yellowtail swim all the way into the final net. These behavioral diŠerences could be used in the development of a technology to separate young bluefin tuna from other catches in set nets.
  • 長谷川浩平, 内田圭一, 宮本佳則
    海洋音響学会誌 44 1 1 - 12 海洋音響学会 2017年01月 [査読有り][通常論文]
  • 宮本佳則, 内田圭一, 甘糟和男, 長谷川浩平, Yuttana Theparoonart, Monton Anongponyoskun, 石川智士, Yap Minlee, 笹倉豊喜
    海洋音響学会誌 43 2 71 - 78 特定非営利活動法人 海洋音響学会 2016年04月 [査読有り][通常論文]
     

    Biological production is thriving in the coastal areas of Southeast Asia. However, resource evaluation has not progressed. In addition, the valid acoustic research needed for resource assessment is not being conducted or disseminated. Therefore, we developed a simple measurement system to perform acoustic investigations and provide basic education. We then conducted a field test in an effort to understand the distribution of fish schools in Tateyama bay, Chiba, Japan. Depth of the target research area was about 20 m. The acoustic device was composed of a GPS plotter and echo sounder (FURUNO GP1670F)+ Interface Box and PC. The concept has been used previously. However, the equipment is simple and easy to use in collecting acoustic data. First, we assumed the amount of resources for recreational boats to measure the distribution of fish using the fish finder. Results confirmed that the system was sufficiently effective.

  • 長谷川浩平, 宮本佳則, 内田圭一
    Fisheries Science 82 2 213 - 223 2016年03月 [査読有り][通常論文]
     
    A system for real-time monitoring the depth of small fishing gear was developed using acoustic telemetry to improve the efficiency of fishing operations. The system consisted of an acoustic transmitter (pinger), an omni-directional hydrophone with a depressor, and a receiver. Using a pinger equipped with a depth sensor, a fisherman can confirm whether the fishing gear is at the intended depth. The battery of the developed pinger can be replaced easily for repeated use. The performance of the system was evaluated in a field experiment. The accuracy of measured depth was 0.4 m and was constant even if the pinger was moving. In the experiment, the system could successfully monitor the pinger depth every several second. The system was implemented in hairtail trolling to examine its effectiveness. The implementation experiments revealed some issues with the system, such as the effect of signal reflections or the installation method of the hydrophone. However, the system could monitor the depth of the fishing gear continuously in real time and it operated successfully without any problem during the fishing operation. Application of the developed system is expected to aid fishermen in adjusting the gear depth easily and accurately.
  • 長谷川浩平, 宮本佳則, 内田圭一, 柿原利治
    海洋音響学会誌 39 4 163 - 172 The Marine Acoustics Society of Japan 2012年10月 [査読有り][通常論文]
     
    Tracking system, one of the biotelemetry systems, detects signals from pingers using a receiver located on an observation boat. This system can be used without location constraints, unlike monitoring systems and positioning systems for which a receiver must be installed in the actual sea. But such a system cannot measure the pinger position in detail. In order to measure the pinger position in greater detail using a tracking system, a new method using "inverse cross bearing" was developed. This method determines the horizontal pinger position using the intersection point of more than two bearing lines from as many observation points. The vertical position of the pinger is measured by a depth sensor on the pinger itself. This system calculates the relative azimuth of the pinger using the receiving time differences among the four transducers. The GNSS compass, to convert the absolute azimuth of the pingers relative azimuth, measures the ships heading. To estimate the theoretical error factors, experiments were conducted in actual seas. The estimation results were compared to the results of the field experiments. In certain conditions, the estimated positioning accuracy was 14 m, and the measured value was 21 m. This discrepancy may be due to factors such as agitation of the ship.

書籍

  • Guide to operation of acoustic data collection system (AQFI-1301) for shallow waters
    Y. Miyamoto, K. Uchida, Y. Theparoonrat, M. Anongponyoskun, K. Thongsila, Y. Minlee, T. Sasakura, K. Hasegawa (担当:共著)
    Research Institute for Humanity and Nature 2017年02月 (ISBN: 9784906888351)

講演・口頭発表等

  • タチウオ曳縄漁業を対象にした漁具深度モニタリングシステムの開発
    長谷川浩平
    令和3年度日本水産学会春季大会第72回漁業懇話会講演会 2021年03月
  • 噴火湾におけるスケトウダラ0歳魚とソウハチの自然状態での広帯域測定
    長谷川浩平
    The 13th Annual Meeting of Asian Fisheries Acoustics Society 2019年11月
  • 遺伝的アルゴリズムを用いた広帯域送受波器の素子配列の最適化
    長谷川浩平
    海洋音響学会2019年度研究発表会 2019年05月
  • 不規則配列を適用した送受波器のビーム特性シミュレーション  [通常講演]
    長谷川 浩平
    海洋音響学会2017年度研究発表会 2017年05月 口頭発表(一般)

その他活動・業績

共同研究・競争的資金等の研究課題

  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2022年04月 -2025年03月 
    代表者 : 長谷川 浩平
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 長谷川 浩平
     
    春季の北海道南部の噴火湾において,カレイの一種であるソウハチのスケトウダラ稚魚に対する捕食圧を評価する方法として,本海域における両種の資源分布の推移を調べることで,両種がどの時期にどの程度の規模で遭遇しているかを推測した。本研究では,本海域で両種が確認できる4月から6月にかけて調査を実施し,4月に噴火湾内の北側で両種ともに多くの資源が分布していることが確認できた。そして,5月から6月にかけて,両種の分布の重なりが小さくなっていったことから,この時期のソウハチによるスケトウダラ稚魚に対する捕食行動は,4月にピークを迎えることが予測できた。
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 向井 徹, 山本 潤, 長谷川 浩平
     
    計量魚群探知機によるソウハチの現存量推定を実現するために,ソウハチの音響特性を野外調査と水槽実験で調べた。音響資源調査に必要な基礎情報を蓄積するとともに,最適な調査時間など特定を行った。まず,野外調査で,計量魚群探知機に写るソウハチの魚群の特徴を調べ,中層でパッチ状になってることがわかった。次に水槽実験でソウハチの反射特性や昼夜における行動の違いを調べ,ソウハチの音響調査は昼間に行うべきという結果がわかった。最後に,野外調査で,ソウハチと遭遇するスケトウダラ稚魚や動物プランクトンについて計量魚群探知機での写り方や周波数による違いを調べ,これらの判別方法を提案した。

教育活動情報

主要な担当授業

  • Introduction to Fisheries Sciences Ⅱ(水産科学汎論Ⅱ)
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 水産科学院
    キーワード : 水産科学,海洋生物学,生物多様性,生物資源, 環境, 資源探査, 漁業技術, 持続可能性, 環境保全, 養殖, 遺伝学, 生命工学, 微生物学, 化学,食糧科学,生物安全性
  • 海洋資源科学実験Ⅰ
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : 海洋音響学、漁具工学、地球流体、情報処理技術、室内実験
  • 水産科学英語Ⅱ
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : 論文講読,プレゼンテーション,海洋資源科学
  • 沿岸実習Ⅰ
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : 海洋環境計測機、水中音響計測機、漁具、採集具、沿岸漁業
  • 沿岸実習Ⅱ
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : 海洋環境計測機、水中音響計測機、漁具、採集具、沿岸漁業
  • 海洋音響学
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : 超音波,魚群探知機,ソナー,流向流速計,海底面探査


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