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Last Updated :2024/10/18

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Master

Affiliation (Master)

  • Faculty of Fisheries Sciences　Marine Bioresource and Environmental Science　Marine Environment and Resource Sensing

Affiliation (Master)

  • Faculty of Fisheries Sciences　Marine Bioresource and Environmental Science　Marine Environment and Resource Sensing

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Profile and Settings

Profile and Settings

  • Name (Japanese)

    Hasegawa

  • Name (Kana)

    Kohei

  • Name

    201801013781490418

Achievement

Research Areas

  • Natural sciences / Atmospheric and hydrospheric science

Published Papers

  • Ryuichi Matsukura, Hanae Doiguchi, Natsuki Yamamoto, Koki Abe, Kazuo Amakasu, Yoshiaki Fukuda, Kohei Hasegawa, Tohru Mukai, Hiroto Murase
    Fisheries Science 0919-9268 2024/09/20
  • Naizheng Yan, Tohru Mukai, Kohei Hasegawa, Jun Yamamoto, Yoshiaki Fukuda
    ICES Journal of Marine Science 81 (1) 195 - 203 1054-3139 2023/12/12 
    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.
  • Yoshiaki FUKUDA, Kohei HASEGAWA, Tohru MUKAI, Tomohito IMAIZUMI
    The Journal of the Marine Acoustics Society of Japan 49 (2) 37 - 45 0916-5835 2022/04 [Refereed]
  • Kohei Hasegawa, Naizheng Yan, Tohru Mukai
    Journal of Marine Science and Technology 29 (2) 135 - 145 1023-2796 2021/05 [Refereed][Not invited]
     
    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.
  • Naizheng Yan, Tohru Mukai, Jun Yamamoto, Kohei Hasegawa
    Fisheries Research 224 105434 - 105434 0165-7836 2020/04 [Refereed][Not invited]
  • Keiichi Uchida, Kohei Hasegawa, Yoshinori Miyamoto, Hisayuki Arakawa, Seiji Akiyama, Naoto Hirakawa
    Oceanography Challenges to Future Earth: Human and Natural Impacts on our Seas 29 - 44 2019/02/15 
    The Great East Japan Earthquake and subsequent tsunami on March 2011 damaged Fukushima Daiichi Nuclear Power Plant (FDNPP), and a part of radioactive materials released from FDNPP entered in coastal waters of north-eastern Japan. Fisheries Cooperative of Fukushima Prefecture has autonomously banned coastal fisheries since 15 March 2011. Japanese Government restricts foods including fishes that contain radioactive cesium (Cs) above the maximum limit of 100 Bq kg-1. Given this serious situation, we have studied whether fishes can transfer radioactive materials to other areas. For this purpose, we selected seven target fish species containing relatively high concentrations of radioactive Cs measured by authorities and monitored their behaviors around rocky beds in the open sea and in a port near the coast off Fukushima Prefecture. The monitoring was performed by an ultrasonic biotelemetry system consisting of fixed receivers and pingers inserted in fish. The results revealed two types of behaviours: site fidelity and migration. Fish species with high concentrations of radioactive Cs preferentially indicated the site fidelity over the migration. A decline of radioactive Cs concentrations in fish may be attributed to a natural decrease overtime and a replacement of contaminated individuals by immigrant ones with a low concentration of radioactive Cs from less contaminated waters.
  • SAWADA KOUICHI, MATSUURA TOMOHIKO, MUKAI TOHRU, FUKUDA YOSHIAKI, HASEGAWA KOHEI, ABE KOKI, SASAKI KEI, YAMADA YUICHIRO
    NIPPON SUISAN GAKKAISHI 公益社団法人 日本水産学会 84 (5) 947 - 947 0021-5392 2018
  • Kouichi Sawada, Tomohiko Matsuura, Kohei Hasegawa, Tohru Mukai, Matt Stone, Kei Sasaki, Hideki Nikaido
    2018 OCEANS - MTS/IEEE KOBE TECHNO-OCEANS (OTO) 2018 
    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.
  • Keiichi Uchida, Hiromichi Ogawa, Kohei Hasegawa, Yoshinori Miyamoto, Hideki Noro, Yuka Wada, Seiji Akiyama
    Nippon Suisan Gakkaishi (Japanese Edition) 84 (1) 14 - 22 1349-998X 2018 [Refereed][Not invited]
     
    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.
  • K. Hasegawa, K. Uchida, Y. Miyamoto
    The Journal of the Marine Acoustics Society of Japan 海洋音響学会 44 (1) 1 - 12 0916-5835 2017/01 [Refereed][Not invited]
  • Y. Miyamoto, K. Uchida, K. Amakasu, K. Hasegawa, Y. Theparoonart, M. Anongponyoskun, S. Ishikawa, Y. Minlee, T. Sasakura
    The Journal of the Marine Acoustics Society of Japan 特定非営利活動法人 海洋音響学会 43 (2) 71 - 78 0916-5835 2016/04 [Refereed][Not invited]
     

    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.

  • Kohei Hasegawa, Yoshinori Miyamoto, Keiichi Uchida
    FISHERIES SCIENCE 82 (2) 213 - 223 0919-9268 2016/03 [Refereed][Not invited]
     
    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.
  • K. Hasegawa, Y. Miyamoto, K. Uchida, T. Kakihara
    The Journal of the Marine Acoustics Society of Japan The Marine Acoustics Society of Japan 39 (4) 163 - 172 0916-5835 2012/10 [Refereed][Not invited]
     
    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.

MISC

Books etc

  • 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 (Joint work)
    Research Institute for Humanity and Nature 2017/02 (ISBN: 9784906888351)

Presentations

  • 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  2021/03
  • In situ broadband acoustic measurements of 0-age walleye pollock and pointhead flounder in Funka Bay
    長谷川浩平
    The 13th Annual Meeting of Asian Fisheries Acoustics Society  2019/11
  • 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  2019/05
  • 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  [Not invited]
    長谷川 浩平
    海洋音響学会2017年度研究発表会  2017/05

Research Projects

  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2024/04 -2028/03 
    Author : Podolskiy Evgeny, 三谷 曜子, 杉山 慎, 深町 康, 長谷川 浩平
  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2022/04 -2025/03 
    Author : 長谷川 浩平
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2019/04 -2022/03 
    Author : Hasegawa Kohei
     
    To estimate predation pressure of pointhead flounder on juvenile walleye pollock in Funka Bay, Hokkaido, We investigated the distribution of the both species in the area. Surveys were conducted from April to June when the both species appears in the area. Relative large school of pointhead flounder and walleye pollock was observed and the distribution of the both species overlapped. The overlapping gradually became smaller in scale in May and in June. The results implied that the predation pressure of pointhead flounder on juvenile walleye pollock was largest in April.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2019/04 -2022/03 
    Author : MUKAI Tohru
     
    The acoustic characteristics of pointhead flounder were investigated by field surveys and tank experiments to realize their acoustic resource survey. We accumulated basic information necessary for acoustic resource surveys and identified the optimum survey season. First, in the field survey, we examined the characteristics of the fish schools of pointhead flounder captured by the quantitative echo sounder, and found that they were patchy in the mid-water layer. Next, tank experiments were conducted to investigate the acoustic characteristics and differences in their behavior during the day and night, as a result, acoustic surveys of pointhead flounder should be conducted during the daytime. Finally, we investigated the differences in the frequency characteristics and the echo shapes by the quantitative echo sounder in field surveys of other fish species and zooplankton overlapping with pointhead flounder, and proposed the method for discriminating these species.

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