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Takagi Tsutomu

Faculty of Fisheries Sciences　Marine Bioresource and Environmental Science　Fisheries EngineeringProfessor
Institute for Academic InnovationProfessor

Researcher basic information

■ Degree
  • (BLANK), Hokkaido University
■ URL
researchmap URL■ Various IDs
J-Global ID■ Research Keywords and Fields
Research Keyword
  • バイオメカニクス
  • 水産流体力学
  • 水産工学
  • 水産物理学
  • Fisheries Fluid Dynamics
  • Fisheries Engineering
Research Field
  • Life Science, Aquatic bioproduction science
  • Life Science, Ecology and environment
  • Frontier Technology (Aerospace Engineering, Marine and Maritime Engineering), Marine engineering
■ Educational Organization

Career

■ Career
Career
  • Sep. 2014 - Present
    Hokkaido University, Faculty of Fisheries Sciences, Prof.
  • Apr. 1999 - Aug. 2014
    Kinki University, Faculty of Agriculture, Dapartment of Fish., Prof.
  • 1997 - 1999
    Marine Ecology and Environment Research Division, JAMSTEC
  • 1996 - 1997
    Special Researcher, Science and Technology Development Foundation
  • 1995 - 1996
    Posdoc researcher, Japan Society for the Promotion and Sciences
  • 1991 - 1993
    神奈川県水産試験場 技師
Educational Background
  • 1996, Hokkaido University, 水産学研究科, 漁業学, Japan
  • 1996, Hokkaido University, Graduate School, Division of Fisheries
  • 1991, Hokkaido University, School of Fisheries Sciences, 漁業, Japan
  • 1991, Hokkaido University, Faculty of Fisheries
Committee Memberships
  • Apr. 2022 - Present
    Society of Aero Aqua Bio-mechanisms, chairperson, Society
  • Apr. 2014 - Present
    日本水産学会, シンポジウム企画委員会委員長, Society
  • Apr. 2007 - Present
    エアロ・アクアバイオメカニズム学会, 委員, Society
  • Apr. 2013 - Mar. 2019
    日本水産学会, 編集委員, Society
  • Apr. 2012 - Mar. 2014
    日本水産学会, 近畿支部幹事, Society
  • Apr. 2012 - Oct. 2013
    日本水産学会, 水産教育推進委員, Society
  • Apr. 2012 - Mar. 2013
    日本水産学会, 漁業懇話会委員長, Society

Research activity information

■ Awards
  • Mar. 2015, 日本水産学会, 水産学技術賞
    髙木 力
  • 2006, the Third International Symposium on Aero Aqua Bio-Mechanisms, Best Presentation Award
    Functional morphology of swimming bluefin tuna based on CFD analysis:I. Effects of morphology on hydrodynamic characteristics
    Yumiko Tamura;TAKAGI Tsutomu;Takeshi Yamane
  • 2004, PICESベストポスタープレゼンテーション賞（共著）
  • 2000, 水産工学奨励賞(日本水産工学会)
    Japan
■ Papers
  • Stability Assessment of a Submersible Net Cage with Vertical Buoyancy Columns Under Steady Currents
    Kengo Yaegashi; Kewen Wang; Shintaro Gomi; Tsutomu Takagi
    Fishes, 11, 2, 92, 92, MDPI AG, 03 Feb. 2026, [Last author, Corresponding author]
    Scientific journal, Offshore aquaculture requires net cages that remain stable under strong currents and during submersion and emergence operations. In this study, we proposed a submersible net cage structure equipped with vertical buoyancy columns as an alternative to the conventional horizontal floating-frame cage and evaluated its stability using a net geometry and load analysis system (NaLA system). Model-scale cages were tested in a recirculating flume tank at two current velocities, and the three-dimensional cage geometry was reconstructed using the multicamera through direct linear transformation method to validate the simulated cage inclination. The NaLA system accurately reproduced the measured geometry and time-varying inclination. After validation, stability was compared over a range of current velocities by tracking the cage inclination during the emergence phase. When mooring lines were attached to the top of the cage, the conventional floating-frame cage exhibited a smaller inclination than the buoyancy-column cage. However, relocating the mooring attachment point on the columns significantly improved the stability; attaching the moorings near the bottom of the columns generated the smallest final inclination and yielded a higher stability than the conventional cage. The buoyancy columns can outperform those of conventional designs when paired with an appropriate mooring configuration, thus offering a promising structure for applications under harsh offshore conditions.
  • Data assimilation reveals behavioral dynamics of sea cucumbers as a model for slow-moving benthic animals
    Tsutomu Takagi; Yuto Tanaka; Erica Sasano; Kouki Kanda; Yuichi Sakai
    SCIENTIFIC REPORTS, 16, 1, 12 Dec. 2025, [Lead author, Corresponding author]
    English, Scientific journal
  • Estimating the Purse Seine Net Geometry during a Hauling Operation Using a Data Assimilation Method
    Shintaro Gomi; Tsutomu Takagi; Katsuya Suzuki; Tatsuki Oshima; Shoko Wada; Rika Shiraki; Yoshihiro Nishiyama; andIchiya Ogino
    Fishes, 9, 10, 392, Sep. 2024, [Peer-reviewed]
    English, Scientific journal
  • Adjustment of Parameters for Numerical Simulation of Fishing Net Dynamics Using a Data Assimilation Method
    Shintaro Gomi; Tsutomu Takagi; Katsuya Suzuki; Tatsuki Oshima; Shoko Wada; Rika Shiraki; Ichiya Ogino; Shigeru Asaumi
    International Journal of Offshore and Polar Engineering, 34, 3, 299, 305, 01 Sep. 2024, [Peer-reviewed]
    English, Scientific journal
  • Drafting behaviors in fish induced by a local pressure drop around a hydrofoil model
    Go Eguchi; Tsutomu Takagi; Shinsuke Torisawa; Kohsei Takehara
    Journal of Theoretical Biology, 588, 111821, 111821, Jul. 2024, [Peer-reviewed]
    English, Scientific journal
  • Quantitative Assessment and Analysis of Fish Behavior in Closed Systems Using Information Entropy
    Minoru Kadota; Shinsuke Torisawa; Tsutomu Takagi
    Fishes, 9, 6, 224, 224, 12 Jun. 2024, [Peer-reviewed], [Last author, Corresponding author]
    English, Scientific journal
  • Fish balances flow resistance and high pressure in stagnation area (in press)
    Go Eguchi; Shinsuke Torisawa; Kohsei Takehara; Tsutomu Takagi
    Journal of Aero Aqua Bio-mechanisms, Jun. 2023, [Peer-reviewed], [Last author]
    English, Scientific journal
  • Hydrodynamics of the sea cucumber <i>Apostichopus japonicus</i> in flow and acceleration fields
    Yuto Tanaka; Yuichi Sakai; Go Eguchi; Tsutomu Takagi
    Journal of Aero Aqua Bio-mechanisms, 10, 1, 24, 32, Study Group of Aero Aqua Bio-mechanics, 2023, [Peer-reviewed], [Last author, Corresponding author]
    Scientific journal
  • New technologies to improve bycatch mitigation in industrial tuna fisheries
    Francois Poisson; Pierre Budan; Sylvain Coudray; Eric Gilman; Takahito Kojima; Michael Musyl; Tsutomu Takagi
    FISH AND FISHERIES, 23, 3, 545, 563, Dec. 2021, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
    English, Scientific journal
  • Development of fish spatio-temporal identifying technology using SegNet in aquaculture net cages
    S. Abe; T. Takagi; S. Torisawa; K. Abe; H. Habe; N. Iguchi; K. Takehara; S. Masuma; H. Yagi; T. Yamaguchi; S. Asaumi
    Aquacultural Engineering, 93, 102146, 102146, Elsevier BV, May 2021, [Peer-reviewed], [Corresponding author], [International Magazine]
    Scientific journal, 33916490
  • Hydrodynamical effect of parallelly swimming fish using computational fluid dynamics method
    Keisuke Doi; Tsutomu Takagi; Yasushi Mitsunaga; Shinsuke Torisawa
    PLOS ONE, 16, 5, May 2021, [Peer-reviewed], [International Magazine]
    English, Scientific journal, 33916489
  • Controlling a Fishing Net Geometry Underwater Using a Data Assimilation Method
    Shintaro Gomi; Tsutomu Takagi; Katsuya Suzuki; Rika Shiraki; Ichiya Ogino; Shigeru Asaumi
    APPLIED OCEAN RESEARCH, 106, Jan. 2021, [Peer-reviewed], [Corresponding author], [International Magazine]
    English, Scientific journal
  • Analysis of sinking death using video images of the swimming performance of Pacific Bluefin tuna (Thunnus orientalis) larvae
    Y. Ina; T. Takagi; S. Miyashita; M. Kurata; T. Honryo; Y. Sawada; H. Fukuda; S. Torisawa
    Aquacultural Engineering, 90, 102099, 102099, Elsevier BV, Aug. 2020, [Peer-reviewed], [International Magazine]
    Scientific journal
  • Mechanical efficiency of fish thrust induced by tail beating: comparison between kinetic energy and metabolic energy
    Eguchi Go; Aoki Yuki; Torisawa Shinsuke; Takehara Kohsei; Takagi Tsutomu
    Journal of Aero Aqua Bio-mechanisms, 8, 1, 54, 62, Society of Aero Aqua Bio-mechanisms, 2019
    English, There are few studies that compare thrust power PT induced by tail beating with net metabolic power Pnet obtained from oxygen consumption and mechanical efficiency η (= PT Pnet -1) of fish thrust. In this study, PT and Pnet were obtained using two species of chub mackerel and Japanese dace, and η was calculated by comparing kinetic energy and metabolic energy. PT was calculated by multiplying swimming speed Vswim and thrust force T obtained using two calculation methods, the Milne-Thomson principle and Kutta-Joukowski theorem. Comparing each value, η showed a certain ratio irrespective of fish species and swimming speed. Linear approximation resulted in PT = 0.21 Pnet for Milne-Thomson and PT = 0.44 Pnet for Kutta-Joukowski.
  • Performance of a multi-stereovision technique to enhance the accuracy of fish body measurement for aquaculture management
    Tatsuya Tanaka; Kazuyoshi Komeyama; Shinsuke Torisawa; Takeharu Yamaguchi; Shigeru Asaumi; Tsutomu Takagi
    NIPPON SUISAN GAKKAISHI, 85, 3, 314, 320, 2019, [Peer-reviewed], [Domestic magazines]
    Japanese, Scientific journal
  • ステレオビジョンによるマサバの3次元遊泳行動計測：パーティクルフィルタを用いた自動計測
    坂本 誠; 米山和良; 田丸 修; 鳥澤眞介; 高木 力
    日本水産学会誌, 84, 5, 787, 795, Jul. 2018, [Peer-reviewed], [Domestic magazines]
  • Development of Non-contact Measure Ring System for Aquaculture Using Image Analysis
    髙木 力; 米山 和良; 阿部 悟; 鳥澤 眞介; 竹原 幸生; 山口 武治; 浅海 茂
    水産工学 = Fisheries engineering, 54, 3, 209, 213, 日本水産工学会, Feb. 2018, [Invited], [Lead author], [Domestic magazines]
    Japanese
  • Particle filter for automated measurement of chub mackerel trajectory using stereo vision
    Makoto Sakamoto; Kazuyoshi Komeyama; Osamu Tamaru; Shinsuke Torisawa; Tsutomu Takagi
    NIPPON SUISAN GAKKAISHI, 84, 5, 787, 795, 2018, [Peer-reviewed], [Domestic magazines]
    Japanese, Scientific journal
  • Body Measurement of Reared Red Sea Bream Using Stereo Vision.
    Kazuyoshi Komeyama; Tatsuya Tanaka; Takeharu Yamaguchi; Shigeru Asaumi; Shinsuke Torisawa; Tsutomu Takagi
    Journal of Robotics and Mechatronics, 30, 2, 231, 237, 2018, [Peer-reviewed], [Domestic magazines]
    English, Scientific journal
  • Development and evaluation of real-time simulation system of purse seine gear dynamics
    N. Tanada; S. Gomi; T. Takagi; K. Komeyama; S. Torisawa; K. Suzuki; R. Shiraki; Y. Nishiyama; S. Asaumi
    Contributions on the Theory of Fishing Gears and Related Marine Systems, 10, 43, 52, Oct. 2017, [Peer-reviewed]
    English, International conference proceedings
  • New technique to shape a fishing ne into arbitary geometry underwater
    S. Gomi; T. Takagi; N. Tanada; K. Komeyama; K. Suzuki; R. Shiraki; Y. Nishiyama; S. Asaumi
    Contributions on the Theory of Fishing Gears and Related Marine Systems, 10, 1, 12, Oct. 2017, [Peer-reviewed]
    English, International conference proceedings
  • Current situation and future issues of implementation of ICT in fisheries industry
    Tsutomu Takagi; Shigeru Asaumi; Shinsuke Torisawa; Masahiko Ariji
    NIPPON SUISAN GAKKAISHI, 83, 1, 91, 91, 2017, [Domestic magazines]
    Japanese, Scientific journal
  • Development of support systems for fishing technology: introduction of ICT in purse seine fishing
    Tsutomu Takagi
    NIPPON SUISAN GAKKAISHI, 83, 1, 92, 92, 2017, [Peer-reviewed], [Domestic magazines]
    Japanese, Scientific journal
  • How Many Fish in a Tank? Constructing an Automated Fish Counting System by Using PTV Analysis
    S. Abe; T. Takagi; K. Takehara; N. Kimura; T. Hiraishi; K. Komeyama; S. Torisawa; S. Asaumi
    SELECTED PAPERS FROM THE 31ST INTERNATIONAL CONGRESS ON HIGH-SPEED IMAGING AND PHOTONICS, 10328, 2017, [Peer-reviewed], [Corresponding author], [International Magazine]
    English, International conference proceedings
  • State-space model for estimating three-dimensional fish trajectories based on acoustic telemetry in large tank
    Kazuyoshi Komeyama; Minoru Kadota; Hiroyuki Sueshige; Kazuhiko Anraku; Tsutomu Takagi
    Fisheries Engineering, 53, 1, 1, 13, The Japanese Society of Fisheries Engineering, Jul. 2016, [Peer-reviewed], [Domestic magazines]
    English, Scientific journal, Three-dimensional fish trajectories were analysed based on acoustic telemetry collected using a large experimental tank （600 m3）and refined with a state-space model to which the Kalman filter was applied. The movements of three red sea bream fitted with acoustic transmitters （at 63, 75, and 84 kHz）were monitored simultaneously using four hydrophones. On the basis of the differences in the times at which the transmitted sound signals arrived at each hydrophone, the positions of the fish were determined as the intersections of hyperboloid functions. A performance test of this system showed that it can be used to detect transmitter positions in a three-dimensional coordinate system with mean accuracy and precision of 0.69 m and 0.02‒0.04 m, respectively, with the 63 kHz transmitter, which generated the best results. The accuracy and precision were better for horizontal measurements than for vertical measurements, and the precision degraded with increasing transmitter frequency. These results indicate that it is possible to improve the precision of the system by employing a sampling rate that is sufficientin relation to the transmitter frequency. Because of the significant error in the measurements, the swimming trajectories were refined using estimates obtained from a state-space model and the Kalman filter. For three of the fish, the estimated horizontal trajectories remained within the boundaries representing the walls of the tank. This study demonstrates that applying a state-space model to acoustic telemetry with large error can produce results that closely approximate the actual swimming trajectories of fish.
  • Towards an Approach to 6 DOF Inertial Kinematics
    Holger Korte; Jan-Hendrik Wesuls; Sven Stuppe; Tsutomu Takagi
    IFAC PAPERSONLINE, 49, 23, 440, 445, 2016, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
    English, International conference proceedings
  • Energy-Saving in Schooling Japanese Mackerel Scomber joponicus and the effect of induced velocity of wake vortices.
    Tsutomu Takagi; Shizuka Ito; Shinsuke Torisawa; Yoshinobu Inada
    Journal of Aero Aqua Bio-mechanisms, 4, 1, 78, 82, Society of Aero Aqua Bio-mechanisms, Jun. 2015, [Peer-reviewed], [Lead author], [Domestic magazines]
    English, A constrained swimming test showed that at fastest flow speeds, the tail-beat frequencies (TBF) of followers in a school of Japanese chub mackerels were significantly lower than those of the leading fish. The gross cost of transport (GCOT) of schooling fish was 4.8-6.6 J·kg-1·m-1, whereas that of solitary swimming fish was significantly larger (9.2-11.5 J·kg-1·m-1). To examine the association between the configuration of individuals in the school and energy-saving, the three-dimensional positions of individuals in a school were measured in a large tank. Although the school was not arranged in the diamond pattern known to be most effective for energy conservation, the TBF of the followers remarkably decreased when within the range of 1.4 BL (Body Length) from the leading fish in the school. The energy gain of schooling fish was greater than that derived from the potential-theory basis, implying a potential hydrodynamic synergy effect.
  • A method for measuring the swimming behaviour of pacific bluefin tuna
    Kazuyoshi Komeyama; Tsutomu Takagi
    Biology and Ecology of Bluefin Tuna, 400, 417, CRC Press, 01 Jan. 2015
    English, In book
  • Schooling behavior of Pacific bluefin tuna
    Hiromu Fukuda; Shinsuke Torisawa; Tsutomu Takagi
    Biology and Ecology of Bluefin Tuna, 292, 308, CRC Press, 01 Jan. 2015
    English, In book
  • Visual physiology
    Shinsuke Torisawa; Hiromu Fukuda; Tsutomu Takagi
    Biology and Ecology of Bluefin Tuna, 309, 324, CRC Press, 01 Jan. 2015
    English, In book
  • Ontogeny of swim bladder inflation and caudal fin aspect ratio with reference to vertical distribution in Pacific bluefin tuna Thunnus orientalis larvae
    Yoshiaki Ina; Wataru Sakamoto; Shigeru Miyashita; Hiromu Fukuda; Shinsuke Torisawa; Tsutomu Takagi
    FISHERIES SCIENCE, 80, 6, 1293, 1299, Nov. 2014, [Peer-reviewed], [Corresponding author], [International Magazine]
    English, Scientific journal
  • Effect of mesh size on sinking characteristics of purse seine net: a parametric study by numerical simulation.
    TAKAGI Tsutomu
    Fisheries Engineering, 51, 1, 11, 19, The Japanese Society of Fisheries Engineering, Jul. 2014, [Peer-reviewed], [Lead author], [Domestic magazines]
    English, Scientific journal, We numerically modeled the geometry of a purse seine net and evaluated the model's dynamic behavior during operation. The vessel position, wire payout and roll-up lengths, and current flow speed and direction in situ were collected as the dataset for computation. The mesh sizes of the upper, middle, and lower sections of the main net were changed to double and half their respective sizes, and the sinking speed and depth were compared among nets of different mesh sizes. The net with doubled mesh size in the lower section and constant mesh bar diameter strongly affected the sinking speed and depth. This implies that a large mesh size in the lower part of the main net, which eliminates the need for providing a thicker mesh bar, should be used for enhancing the efficiency of fishing operations.
  • Ontogenetic changes in schooling behavior and visual sensitivity during larval and juvenile stages in Pacific bluefin tuna, Thunnus orientalis
    Hiromu Fukuda; Shinsuke Torisawa; Tsutomu Takagi
    BULLETIN OF FISHERIES RESEARCH AGENCY, 38, 135, 139, Mar. 2014, [Peer-reviewed], [Last author], [Domestic magazines]
    English, International conference proceedings
  • 網漁具の形状・荷重シミュレータNaLA-Systemについて
    鈴木 勝也; 髙木 力
    ていち, 125, 10, 19, Feb. 2014, [Domestic magazines]
    Japanese, Research society
  • Hydrodynamics and energy-saving swimming techniques of Pacific bluefin tuna
    Tsutomu Takagi; Yumiko Tamura; Daniel Weihs
    Journal of Theoretical Biology, 336, 158, 172, 07 Nov. 2013, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
    English, Scientific journal
  • Potential of computer simulation for buoy-line type of purse seine fishing
    T TAKAGI; S MIYATA; I FUSEJIMA; T OSHIMA; T UEHARA; K SUZUKI; Y NOMURA; M Kanechiku; S TORISAWA
    Contributions on the Theory of Fishing Gears and Related Marine Systems, 8, 55, 62, Oct. 2013, [Peer-reviewed], [Lead author, Corresponding author]
    English, International conference proceedings
  • Dynamic modeling for fishing gear and its numerical simulation
    Tsutomu Takagi
    NIPPON SUISAN GAKKAISHI, 79, 5, 778, 781, Sep. 2013, [Lead author, Corresponding author], [Domestic magazines]
    Japanese, Scientific journal
  • Three-dimensional trajectories of cultivated Pacific bluefin tuna Thunnus orientalis in an aquaculture net cage.
    Kazuyoshi Komeyama; Minoru Kadota; Shinsuke Torisawa; Tsutomu Takagi
    Aquaculture Environment Interactions, 4, 1, 81, 90, Jun. 2013, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Energy Saving Effect of Fish Schooling in the Japanese Mackerel, Scomber joponicus.
    Tsutomu Takagi; Shizuka Ito; Shinsuke Torisawa; Yoshinobu Inada
    Mathmatical and Physical Fisheries Science, 10, 2, 13, May 2013, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
    English
  • アーカイバルタグを用いた幼魚期における養殖クロマグロの異常行動検出の試み
    米山 和良; 近藤 了太郎; 藤岡 紘; 門田 実; 安樂 和彦; 鳥澤 眞介; 高木 力
    日本水産工学会 学術講演会 学術講演論文集, 2013, 59, 62, 日本水産工学会, 2013
    Japanese
  • II-1. Computational modeling of fishing net
    Tsutomu Takagi
    Nippon Suisan Gakkaishi (Japanese Edition), 78, 5, 1018, 2012, [Lead author, Corresponding author], [Domestic magazines]
    English, Scientific journal
  • Constructing a mathematical model of fishery system, and estimating ideal aquaculture and catch-fishery products.
    Minoru Kadota; Shinsuke Torisawa; Takeshi Yamane; Tsutomu Takagi
    Fisheries Engineering, 48, 3, 197, 203, The Japanese Society of Fisheries Engineering, 2012, [Peer-reviewed], [Domestic magazines]
    English, The balance between capture fishery and aquaculture production is extremely important for maintaining and developing the fishery industry. In this study, we addressed the problem of optimizing aquaculture and capture fisheries production from the viewpoint of effectively using finite aquatic resources. Our goal was to maximize total fishery production by controlling the ratio of aquaculture to capture fishery production. A simple mathematical model was constructed to describe total fishery production as the sum of capture fishery production and aquaculture production. This model did not consider any economic aspects, but simply focused on the production flow. Aquaculture and capture fishery production interacted in the model via the parameter α, which was defined as the ratio of capture fishery production that turned into aquaculture bait. It was assumed that there was a bounded exponential curve relationship between the amount of bait used in aquaculture and aquaculture production. It was also assumed that aquaculture production was not used for bait in aquaculture or capture fishery. Within this framework, total production was critically dependent on the parameter α. We also analyzed the FAO data (nonfood uses, aquaculture, and capture production data were used). The results indicated that total fishery production was maximized if the amount of the bait used in aquaculture is limited to about 15% of capture fishery production. Sensitivity analysis also indicated that the upper bound of α should be maintained at less than 18.9% to maximize total fishery production.
  • A method of three-dimensional monitoring of free-swimming Pacific bluefin tuna, Thunnus orientalis, cultured in a net cage using a digital stereo-video camera system.
    Shinsuke Torisawa; Minoru Kadota; Kazuyoshi Komeyama; Tsutomu Takagi
    Fisheries Engineering, 49, 1, 13, 20, The Japanese Society of Fisheries Engineering, 2012, [Peer-reviewed], [Last author], [Domestic magazines]
    English, A digital stereo-camera system was used for 3-dimensional monitoring of cultured Pacific blufin tuna Thunnus orientalis individuals, which were free-swimming in a net cage. The fork lengths and the length frequency distribution of tuna individuals in a net cage were estimated using the Direct Linear Transformation (DLT) method. Information obtained from stereo-images is useful for managing the growth of tuna during rearing. In this research, we are trying to develop the simple method involving a combination of DLT and a commercial image processing software to enable aquaculturists to obtain three-dimensional measurements of fish. Then, we used a digital stereo-video camera system to evaluate the precision and validity of fish size estimates determined from repeated measurements. Of the total assessed individuals swimming within a distance of <9.2m from the camera system, estimates for 100% (37/37) were found to be valid, with an error ratio (standard error/mean) of 5%. Therefore, we believed that our proposed simple non-destructive method for monitoring free-swimming fish could be very useful for aquaculture management.
  • Employing relative entropy techniques for assessing modifications in animal behavior
    Minoru Kadota; Eric J. White; Shinsuke Torisawa; Kazuyoshi Komeyama; Tsutomu Takagi
    PLoS ONE, 6, 12, e28241, 02 Dec. 2011, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
    English, Scientific journal
  • Analysis of juvenile tuna movements as correlated random walk
    Minoru Kadota; Shinsuke Torisawa; Tsutomu Takagi; Kazuyoshi Komeyama
    Fisheries Science, 77, 6, 993, 998, Nov. 2011, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Schooling behaviour of juvenile Pacific bluefin tuna Thunnus orientalis depends on their vision development
    S. Torisawa; H. Fukuda; K. Suzuki; T. Takagi
    Journal of Fish Biology, 79, 5, 1291, 1303, Nov. 2011, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Seasonal distribution of adult crucian carp nigorobuna Carassius auratus grandoculis and gengoroubuna Carassius cuvieri in Lake Biwa, Japan
    Yoshio Kunimune; Yasushi Mitsunaga; Kazuyoshi Komeyama; Masanari Matsuda; Toru Kobayashi; Tsutomu Takagi; Takeshi Yamane
    Fisheries Science, 77, 4, 521, 532, Jul. 2011, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Ontogenetic changes in behaviour transmission among individuals in the schooling of Pacific bluefin tuna Thunnus orientalis
    Hiromu Fukuda; Yoshifumi Sawada; Tsutomu Takagi
    AQUATIC LIVING RESOURCES, 24, 2, 113, 119, Apr. 2011, [Peer-reviewed], [Last author], [International Magazine]
    English, Scientific journal
  • A digital stereo-video camera system for three-dimensional monitoring of free-swimming Pacific bluefin tuna, Thunnus orientalis, cultured in a net cage
    Shinsuke Torisawa; Minoru Kadota; Kazuyoshi Komeyama; Katsuya Suzuki; Tsutomu Takagi
    Aquatic Living Resources, 24, 2, 107, 112, Apr. 2011, [Peer-reviewed], [Last author], [International Magazine]
    English, Scientific journal
  • Measuring the swimming behaviour of a reared Pacific bluefin tuna in a submerged aquaculture net cage
    Kazuyoshi Komeyama; Minoru Kadota; Shinsuke Torisawa; Katsuya Suzuki; Yuichi Tsuda; Tsutomu Takagi
    Aquatic Living Resources, 24, 2, 99, 105, Apr. 2011, [Peer-reviewed], [Last author], [International Magazine]
    English, Scientific journal
  • Concernment of rheotactic reaction and schooling behaviour traits of the dwarf sweetfish, Plecoglossus altivelis on a capture process of the set-net “eri”.
    FUKUDA Hiromu; TORISAWA Shinsuke; YAMANE Takeshi; TAKAGI Tsutomu
    Fisheries Engineering, 48, 2, 117, 124, The Japanese Society of Fisheries Engineering, 2011, [Peer-reviewed], [Last author], [Domestic magazines]
    English, We investigated schooling behaviour and the rheotactic reaction in the dwarf sweetfish Plecoglossus altivelis. Under 400lx illumination, the fish formed schools with low polarity; these aggregations were highly compact. There was no schooling behaviour in darkness (0.01lx). A positive rheotactic reaction occurred at current velocities >3.3cm s^<-1>. At current speeds ≥5.2cm s^<-1>, fish ground speeds declined to zero. There was no clear rheotaxis at current speeds <3.3cm s^<-1>. These results suggested that the stimuli by these slow currents might be too weak to increase the rheotaxis of P. altivelis. Current speed was thus an important factor affecting swimming effort and direction in P. altivelis. Current effects may be particularly strong in dwarf sweetfish because the schools have low polarity.
  • Developmental changes in behavioral and retinomotor responses of Pacific bluefin tuna on exposure to sudden changes in illumination
    Hiromu Fukuda; Shinsuke Torisawa; Yoshifumi Sawada; Tsutomu Takagi
    AQUACULTURE, 305, 1-4, 73, 78, Jul. 2010, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
    English, Scientific journal
  • Ontogenetic changes in schooling behaviour during larval and early juvenile stages of Pacific bluefin tuna Thunnus orientalis
    H. Fukuda; S. Torisawa; Y. Sawada; T. Takagi
    JOURNAL OF FISH BIOLOGY, 76, 7, 1841, 1847, May 2010, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
    English, Scientific journal
  • Functional morphology of the flounder allows stable and efficient gliding: an integrated analysis of swimming behaviour
    Tsutomu Takagi; Ryo Kawabe; Hiroyuki Yoshino; Yasuhiko Naito
    AQUATIC BIOLOGY, 9, 2, 149, 153, 2010, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
    English, Scientific journal
  • Morphological features and functions of bluefin tuna change with growth
    Yumiko Tamura; Tsutomu Takagi
    FISHERIES SCIENCE, 75, 3, 567, 575, May 2009, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
    English, Scientific journal
  • 幼魚期の成長に伴うクロマグロ魚群の個体間相互作用の変化
    髙木 力; 石橋 泰典; 福田漠生; 倉田道雄; 澤田
    日本水産学会講演要旨集, 166, Mar. 2009
  • 遊泳するクロマグロ幼魚の推進力と抗力の推定
    髙木 力; 田村優美子
    日本水産学会講演要旨集, 166, Mar. 2009
  • クロマグロ沖合養殖施設の研究開発-Ⅲ NaLAを用いた波浪・流動環境における生簀網形状の数値解析
    髙木 力; 鈴木勝也; 鳥澤眞介
    日本水産学会講演要旨集, 13, 日本水産学会大会春季大会, Mar. 2009
  • クロマグロ沖合養殖施設の研究開発-Ⅱ 実海域における大型養殖施設の動態計測
    髙木 力; 鳥澤眞介; 鈴木勝也; 鉛 進; 沼口隆之; 小林次彦
    日本水産学会講演要旨集, 13, Mar. 2009
  • クロマグロ沖合養殖施設の研究開発-Ⅰ 最適な設計技術の構築を目指して
    髙木 力; 鈴木勝也; 鳥澤眞介; 鉛 進; 沼田隆之; 小林次彦
    日本水産学会講演要旨集, 13, 日本水産学会大会春季大会, Mar. 2009
  • High-frequency depth recording reveals the vertical movement of flounder in the Tsugaru Strait of northern Japan
    Ryo Kawabe; Nagayasu Yoshiura; Katsuaki Nashimoto; Yuichi Tsuda; Takahito Kojima; Tsutomu Takagi; Tohya Yasuda; Akiko Kato; Katsufumi Sato; Yasuhiko Naito
    MARINE AND FRESHWATER BEHAVIOUR AND PHYSIOLOGY, 42, 4, 275, 295, 2009, [Peer-reviewed], [International Magazine]
    English, Scientific journal
  • Numerical analysis of net cage dynamic behavior due to concurrent waves and current
    Katsuya Suzuki; Shinsuke Torisawa; Tsutomu Takagi
    Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 4, 1513, 1520, 2009, [Peer-reviewed]
    English, International conference proceedings
  • Analysis of fish movement using a genetic algorithm: factors influencing the occurrence of fish near a set-net
    K. Komeyama; K. Suzuki; T. Takagi; Y. Mitsunaga; T. Yamane; T. Hiraishi
    FISHERIES MANAGEMENT AND ECOLOGY, 15, 5-6, 347, 355, Oct. 2008, [Peer-reviewed], [Corresponding author], [International Magazine]
    English, Scientific journal
  • クロマグロ幼魚の推進エネルギーと移動コスト視覚特性が群行動に与える影響
    髙木 力; 石橋 泰典; 山根 猛; 福田漠生; 鈴木勝也; 山根猛; 澤田好史; 岡
    日本水産学会講演要旨集, 173, 日本水産学会大会春季大会, Mar. 2008
  • Numerical analysis of dynamic behavior of Danish seining and sea trial verification,
    SUZUKI K.
    Mathematical and Physical Fisheries Science, 6, 6, 11, 22, 2008
  • Dynamics of boat seine fishing using a net geometry simulator
    Katsuya Suzuki; Tsutomu Takagi
    Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 3, 865, 870, 2008, [Peer-reviewed]
    English, International conference proceedings
  • Evaluating the impact of gillnet ghost fishing using a computational analysis of the geometry of fishing gear
    Tsutomu Takagi; Takashi Shimizu; Holger Korte
    ICES JOURNAL OF MARINE SCIENCE, 64, 8, 1517, 1524, Nov. 2007, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
    English, Scientific journal
  • Evaluating developmental changes in schooling behavior in cultivated Pacific bluefin tuna Thunnus orientalis using a mathematical model
    H FUKUDA; S TORISAWA; K SUZUKI; Y ISHIBASHI; M KURATA; Y SAWADA; T TAKAGI; T YAMANE
    Contributions on the Theory of Fishing Gears and Related Marine Systems, 5, 297, 305, Nov. 2007, [Peer-reviewed]
    English, International conference proceedings
  • Changes in the retinal cone density distribution and the retinal resolution during growth of juvenile Pacific bluefin tuna Thunnus orientalis
    Shinsuke Torisawa; Tsutomu Takagi; Yasunori Ishibashi; Yoshifumi Sawada; Takeshi Yamane
    FISHERIES SCIENCE, 73, 5, 1202, 1204, Oct. 2007, [Peer-reviewed]
    English, Scientific journal
  • Schooling behaviour and retinomotor response of juvenile Pacific bluefin tuna Thunnus otientalis under different light intensities
    S. Torisawa; T. Takagi; H. Fukuda; Y. Ishibashi; Y. Sawada; T. Okada; S. Miyashit; K. Suzuki; T. Yamane
    JOURNAL OF FISH BIOLOGY, 71, 2, 411, 420, Aug. 2007, [Peer-reviewed]
    English, Scientific journal
  • Application of NaLA, a fishing net configuration and loading analysis system, to bottom gill nets
    Takashi Shimizu; Tsutomu Takagi; Holger Korte; Tomonori Hiraishi; Katsutaro Yamamoto
    FISHERIES SCIENCE, 73, 3, 489, 499, Jun. 2007, [Peer-reviewed], [Corresponding author]
    English, Scientific journal
  • Using a netting geometry simulator to develop smart fishing and smart gear
    Tsutomu Takagi; Takashi Shimizu; Holger Korte; Katsuya Suzuki
    Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 5, 45, 52, 2007, [Peer-reviewed], [Lead author, Corresponding author]
    English, International conference proceedings
  • Mathematical and experimental analysis of schooling behavior during growth in juvenile chub mackerel: Considerations of population density and space limitation
    Katsuya Suzuki; Shinsuke Torisawa; Tsutomu Takagi
    Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 5, 69, 75, 2007, [Peer-reviewed]
    English, International conference proceedings
  • Quantitative analysis of schooling behaviour and retinomotor response in juvenile Pacific bluefin tuna under different light intensities
    髙木 力; Torisawa Shinsuke; Fukuda Hiromu; Ishibashi Yasunori; Suzuki Katsuya; Yamane Takeshi; Sawada Yoshifumi; Okada Tokihiko; Miyashita Shigeru
    Mathematical and Physical Fisheries Science, 4, 2, 6, 2006
  • 数値シミュレーションを用いた障害物に対する魚群の回避行動の定量的評価
    鈴木 勝也; 髙木 力; 宮下 和士
    数理水産科学, 4, 23, 28, 数理水産科学研究会, 2006
    Japanese
  • Video analysis of the schooling behavior of juvenile chum salmon under light and dark conditions using a mathematical model
    Katsuya SUZUKI; Tsutomu TAKAGI; Kazushi MIYASHITA
    NPAFC Technical Report, 7, 131, 132, 2006
  • Application of NaLA, a fishing net configuration and loading analysis system, to drift gill nets
    T. Takagi; Shimizu Takashi; Holger Korte; Hiraishi Tomonori; Yamamoto Katsutaro
    FISHERIES RESEARCH, 76, 1, 67, 80, Oct. 2005, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
    English, Scientific journal
  • Application of Net shape simulator “NaLA” to gill net
    T SHIMIZU; T TAKAGI; K SUZUKI; T HIRAISHI; K YAMAMOTO
    Contributions on the Theory of Fishing Gears and Related Marine Systems, 4, 29, 36, Oct. 2005, [Peer-reviewed]
    English, International conference proceedings
  • Possibilities of integrative analysis using net shape simulator “NaLA” and CFD for estimation of flow characteristics near fishing net,
    T TAKAGI; H YOSHINO; T SHIMIZU; K SUZUKI
    Contributions on the Theory of Fishing Gears and Related Marine Systems, 3, 245, 250, Oct. 2005, [Peer-reviewed]
    English, International conference proceedings
  • ﾊﾞｲｵﾛｷﾞﾝｸﾞとバイオメカニクスの総合研究によるヒラメのtailbeat-and-glide行動の解析
    髙木 力; 河邊玲
    第36回北洋シンポジュウム, 2, Feb. 2005
    海洋生態系における高次捕食者の行動研究のための新技術
  • 魚群行動における視覚と側線感覚機能の数理モデルによる評価
    鈴木 勝也; 髙木 力; 鳥澤 眞介; 福田 漠生; 村田 修; 山本 眞司; 宮下 和士
    数理水産科学, 3, 15, 20, 数理水産科学研究会, 2005
    Japanese
  • 明暗によるチカ Hypomesus japonicus 魚群の遊泳行動の変化
    鈴木 勝也; 高木 力; 宮下 和士
    日本水産工学会学術講演会講演論文集, 16, 195, 196, 2004
    Japanese
  • 異なる光環境下における魚群の行動特性について
    鈴木 勝也; 高木 力; 鳥澤 眞介; 宮下 和士
    数理水産科学, 2, 37, 42, 2004
  • Validity and visualization of a numerical model used to determine dynamic configurations of fishing nets
    K Suzuki; T Takagi; T Shimizu; T Hiraishi; K Yamamoto; K Nashimoto
    FISHERIES SCIENCE, 69, 4, 695, 705, Aug. 2003, [Peer-reviewed], [Corresponding author]
    English, Scientific journal
  • 漁具性能の科学的性能（漁具工学の数値シミュレーション技術とその可能性について
    髙木 力
    日本水産工学会講演論文集, 247, 248, May 2003
  • Performance of “NaLA”: a fishing net shape simulator
    TAKAGI T
    Fisheries engineering, 40, 2, 125, 134, 日本水産工学会, 2003, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
    English, 著者らは水中での網地形状と荷重をコンピュータによって推定できる汎用性の高いシステム"NaLA"（Net shape configuration and Loading Analysis system）の実用化を目指してその開発に取り組んでいる。網地形状と荷重は数値計算により算定されパーソナルコンピュータ上に3次元的に視覚化される。本論文ではNaLAによって得られた推定結果を水槽実験とトロール網形状推定ソフトウェアDynamiTと比較し、その性能を評価した。計算モデル内の抗力係数をレイノルズ数の関数とすることで網地の形状とそれに作用する荷重は水槽実験の結果とよく一致することが確認された。NaLAとDynamiTとの性能を比較したところ、NaLAでは早い段階で平衡状態の網形状を得ることができたが、DynamiTでは網地の脚や曳航索が折れ曲がり、網形状が不安定な状態になることが確認され不合理な結果が得られた。これらの結果からNaLAの計算モデルで得られる推定結果は精度、汎用性や実用性の面でより適切なものであることが確
  • 閉鎖空間内における魚群行動の確率モデル
    鈴木 勝也; 高木 力; 守冨 裕; 鳥澤 眞介; 宮下 和士
    数理水産科学, 1, 15, 20, 2003
  • Development of the numerical simulation method of dynamic fishing net shape
    T Takagi; K Suzuki; T Hiraishi
    NIPPON SUISAN GAKKAISHI, 68, 3, 320, 326, May 2002, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
    Japanese, Scientific journal
  • Modeling of net for calculation method of dynamic fishing net shape
    Tsutomu Takagi; Katsuya Suzuki; Tomonori Hiraishi
    Fisheries Science, 68, sup2, 1857, 1860, 2002, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
    English, Scientific journal
  • Calculation and visualization method of dynamic fishing net shape
    Tsutomu TAKAGI; Katsuya SUZUKI; Tomonori HIRAISHI
    Contributions on the Theory of Fishing Gears and Related Marine Systems, 2, 159, 172, Nov. 2001, [Peer-reviewed]
    English, International conference proceedings
  • 成長ステージと個体数の違いによるマサバ魚群の遊泳行動の変化
    鈴木 勝也; 守冨 裕; 高木 力; 山根 猛; 村田 修
    日本水産工学会学術講演会講演論文集, 13, 177, 178, 2001
    Japanese
  • Computer Simulation for Netting Gear Design (Hydrodynamic Aspects of Fishing Gears : II. Practical Researches)
    TAKAGI Tsutomu; Tsutomu Takagi; Faculty of Agriculture Kinki University
    NSUGAF, 66, 5, 901, 902, The Japanese Society of Fisheries Science, 15 Sep. 2000
    Japanese
  • 円柱構造物に対する魚群の遊泳行動
    鈴木 勝也; 高木 力; 山根 猛
    日本水産工学会学術講演会講演論文集, 221, 222, 2000
  • Wave Loads and Responses of Fishing Gears (Hydrodynamic Aspects of Fishing Gears : I Basic Researches)
    TAKAGI Tsutomu; Tsutomu Takagi; Faculty of Agriculture Kinki University
    NSUGAF, 65, 5, 925, 926, The Japanese Society of Fisheries Science, 15 Sep. 1999
    Japanese
  • SELECTIVITY OF TRAPS FOR WHELKS NEPTUNEA-ARTHRITICA
    K NASHIMOTO; K SUZUKI; T TAKAGI; K MOTOMATSU; T HIRAISHI
    NIPPON SUISAN GAKKAISHI, 61, 4, 525, 530, Jul. 1995, [Peer-reviewed]
    Japanese, Scientific journal
  • FISH SCHOOLING BEHAVIOR IN WATER TANKS OF DIFFERENT SHAPES AND SIZES
    T TAKAGI; K NASHIMOTO; K YAMAMOTO; T HIRAISHI
    NIPPON SUISAN GAKKAISHI, 59, 8, 1279, 1287, Aug. 1993, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
    Japanese, Scientific journal
■ Other Activities and Achievements
■ Books and other publications
  • Contributions on the theory of fishing gears and related, Marine systems
    2002
  • 漁具物理学
    成山堂書店, 2001
  • Fishing Gear Phisics
    2001
  • Contributions on the Theory of Fishing Gears and Related Marine Systems
    NEUER HOCHSCHULSCHRIF TENVIRLAG, 2000
■ Syllabus
  • 海洋生物環境学基礎論, 2024年, 修士課程, 環境科学院
  • 海洋生物圏環境科学特論Ⅰ, 2024年, 修士課程, 環境科学院
  • 生物圏科学実習Ⅰ, 2024年, 修士課程, 環境科学院
  • 生物圏科学実習Ⅱ, 2024年, 修士課程, 環境科学院
  • 環境と人間, 2024年, 学士課程, 全学教育
  • 科学・技術の世界, 2024年, 学士課程, 全学教育
  • 海洋資源科学実験Ⅲ, 2024年, 学士課程, 水産学部
  • 水産科学英語Ⅰ, 2024年, 学士課程, 水産学部
  • 応用物理学, 2024年, 学士課程, 水産学部
  • 特別講義Ⅰ, 2024年, 学士課程, 水産学部
  • 水産物理学入門, 2024年, 学士課程, 水産学部
■ Affiliated academic society
  • アクアバイオメカニズム研究会
  • 日本水産学会
  • 日本水産工学会
■ Research Themes
  • Mechanisms of Long-Distance Migration in Migratory Fish Species
    Grants-in-Aid for Scientific Research
    01 Apr. 2025 - 31 Mar. 2029
    高木 力; 五味 伸太郎; 菊地 謙次; 竹原 幸生
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 25K01181
  • Understanding and controlling fish schools for selective fishing
    Grants-in-Aid for Scientific Research
    01 Apr. 2024 - 31 Mar. 2028
    若宮 直紀; 小蔵 正輝; 高木 力; 鳥澤 眞介
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), The University of Osaka, 24H00743
  • 鰭の柔らかさと動きのしなやかさがもたらす移動能力と機動性向上の解明
    科学研究費助成事業 基盤研究(C)
    01 Apr. 2022 - 31 Mar. 2025
    高木 力; 鳥澤 眞介; 竹原 幸生
    日本学術振興会, 基盤研究(C), 北海道大学, 22K03977
  • 魚群行動の流体力学的機能性の解明
    科学研究費助成事業 基盤研究(C)
    01 Apr. 2020 - 31 Mar. 2023
    鳥澤 眞介; 竹原 幸生; 高木 力
    賢く獲る漁業技術の開発が近年求められているが，生産手段の最適化は対象生物(魚類)の行動特性を理解せずには実現できない。したがって，魚類の群行動についての基本的理解とそのための研究は不可欠である。
    本研究では，魚類が群れを形成する意味を物理的側面からアプローチすることにより，その本質的意義の解明を目指す。背景となる力学的論理基盤から群を形成したことによる移動エネルギーコストの利得が単一個体よりどの程度のアドバンテージとなり，魚群の規模によりどのような差がでるのかを明らかにする。これをベースにして，種の違いによる魚群の移動距離・速度とエネルギーコストの適値と限界，また群を形成する種がなぜその魚群規模となるのか，その極限や最適規模，さらに魚群の立体構造の必然性や最適性について，一つの体系的理論からこれらの説明や解釈を可能とする革新的アプローチ手法の確立を試みている。
    PTV（流体可視化計測）実験では，マアジを対象種として3尾で形成される魚群を回流水槽で巡航遊泳させ，群泳時の魚体後流域の流況可視化実験を2種類のレーザー光源と高速カメラを用いて2日間にわたり2回実施した。現在は当該実験で撮影した画像から流況を明かにするために，魚体後流域の流速ベクトルや渦度分布の解析を実施中である。
    CFD（数値流体力学）解析実験では，ビワマスを対象種としてデジタルビデオカメラで撮影した遊泳運動から魚体の遊泳運動関数を算定した後，並列遊泳する2尾の魚体モデルに遊泳運動を与えて群泳を再現し，数値流体力学解析により魚体モデルに作用する圧力とその分布を算出することで流体力学的効果を求めた。並列で遊泳する個体は個体間の距離を全長の0.4倍から2.0倍まで変化させた場合，0.4全長倍距離のとき推進効率が最も良く，尾鰭の振動が互いに逆位相のとき，単体で遊泳するよりも推進効率が約10%向上することを明かにした。
    日本学術振興会, 基盤研究(C), 近畿大学, 20K04355
  • 情報科学と画像解析を応用した新技術展開による養殖魚成育生産管理システムの開発
    科学研究費助成事業 基盤研究(B)
    01 Apr. 2018 - 31 Mar. 2022
    高木 力; 竹原 幸生; 鳥澤 眞介; 阿部 孝司; 米山 和良; 井口 信和
    魚類養殖産業では生産物が水面下にあるため日常的に求められる生産管理や成育状態の把握が困難となっている。こうした背景からICT導入による効率化が検討されている。
    本研究では，魚類養殖の成育・生産を効率化するシステムの構築を目指して，非接触で養殖魚の収容数や生育状態を計測する基盤技術開発に取り組む。
    【個体数計数システムの開発】本システムは取得された画像情報から個体画像を抽出する過程とその個体画像を連続画像上で追跡し，各個体の移動ベクトルを推定する二つの解析パートで構成されている。H30年度は，生簀内を遊泳する養殖魚を撮影した画像情報から個体画像を抽出するアルゴリズムの基盤部分の構築を行った。深層学習による個体画像識別の有効性を確認した。検出対象を塗り分けた画像と元画像をペアとした教師データを用いて検出対象を画像的に識別するSegNetとよばれる深層学習法を適用することにより，養殖魚の個体画像を関心領域として抽出することを行った。その結果，実験水槽レベルでは学習画像データ100枚を用いて，2層構造SegNetを適用することで個体画像抽出が可能となった。この成果を実海域に応用することによりクロマグロ養殖場での養殖魚個体の画像抽出を行い，最適なSegNetの学習パラメータを探索する。
    【非接触型個体サイズ推定システムの開発】DLT法を用いて複数のカメラから三次元位置座標を推定し，養殖魚の尾叉長等の成長状態を把握するシステムの開発を行った。直方体状キャリブレーションフレームを用いてカメラシステムを較正し計測誤差を抑制した。これにより養殖魚の体サイズは直接生簀から捕獲せずに，非接触で体サイズを定量化することができる。直接計測したものと本方法から算定された結果を比較したところ，直接計測との有意差は認められず本方法の有効性を確認することができた。
    日本学術振興会, 基盤研究(B), 北海道大学, 18H02260
  • Development of algorithm for number of swimming fish individuals: a new approach by using PTV technique
    Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
    01 Apr. 2015 - 31 Mar. 2017
    KIMURA Nobuo; KOMEYAMA Kazuyoshi; TORISAWA Shinsuke; HIRAISHI Tomonori
    To develop the fundamental technique of counting number of fish individuals in an aquaculture cage, the basic algorithm for counting individuals was constructed by applying PTV (Particle Tracking Velocimetry) technique. The region above a certain area and brightness was defined as the candidate region of an individual. The movement vectors of the extracted regions were estimated by using Kalman filter, and the number of the vectors was possible to give that of individuals. When 200 individuals were put in an experimental tank, applying the algorithm showed that the averaged error was 5.9% and its availability was confirmed.
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 15K14785
  • Elucidation of capture process and mechanism of purse seine tuna fishing by using ICT
    Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    01 Apr. 2014 - 31 Mar. 2017
    Takagi Tsutomu; TORISAWA Shinsuke; MITSUNAGA Yasushi; KAWABE Ryo; KADOTA Minoru
    To assess the capture process during purse seine fishing of tuna species, the dynamic geometries of the purse seine fishing net under some operations were investigated by using a numerical simulation technique as well as by obtaining three-dimensional swimming paths of three bigeye tuna individuals during the purse seine fishing operation through dead-reckoning algorithms. The vectors of the swimming paths showed great variations in the vertical and horizontal directions. The hem of the purse seine net reached up to 200 m in depth, whereas the tuna individuals swam at depths shallower than 100 m and their swimming speeds decreased by 30% after pursing. The simulation results revealed that by 1500 s after casting the net, immature bigeye tunas could not pass through the body net because of the meshes of the net stretching in the longitudinal direction.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 26450269
  • Development of multi-dimensional information gathering system by using a collective motion control of aerial and ground vehicles
    Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    01 Apr. 2011 - 31 Mar. 2014
    INADA YOSHINOBU; TAKANOBU Hideaki; TAKAGI Tsutomu
    Biologically-inspired collective motion control was investigated to enhance the availability of mini-size air vehicles or ground vehicles for information gathering. The control model consists of three components, i.e. attraction, repulsion, and parallel orientation, which are based on the motion of fish school or bird flock. The effectiveness of the model was tested on the various types of vehicles, e.g. ground vehicles, airship, fixed and rotary wing type airplanes. In consequence, all or a part of the three components of collective motion control were successfully functioned on these vehicles. Furthermore, the cooperation between heterogeneous vehicles, i.e. airship and ground vehicles, was succeeded. The characteristics of fish school were also investigated and the change of group formation parameters with the stage of growth and the optimal positioning of individuals in the school to reduce the energy consumption were clarified.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Tokai University, 23360382
  • Optimum design for an offshore aquaculture facility for Pacific bluefintuna on the basis of its behavioral aspects
    Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    2010 - 2012
    TAKAGI Tsutomu; KOMEYAMA Kazuyoshi; TORISAWA Shinsuke; SUZUKI Katsuya; KAWABE Ryo; KADOTA Minoru
    In the present study, we tried to create the basis for an optimum design for an offshore aquaculture facility for Pacific bluefin tuna (PBT) from not only mechanical aspects but also biological ones after considering the behavior of PBT. We used a numerical simulation system of the netting geometry developed by us to evaluate net deformation and the loads to the facility. The simulation results showed that the net cage was deformed and reduced to 50% of the original volume by current flow when the speed was 1 kt. The observation data obtained using a bio-telemetry system showed that the strong current blew up the net cage and caused a collision between the netting and the cultured tuna. In addition, the cold water mass acted as a strong constraint factor on the vertical swimming of PBT.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Kinki University, 22580214
  • Analysis of the swimming behavior of cultivated Pacific bluefin tuna following a change in environment
    Grants-in-Aid for Scientific Research Grant-in-Aid for Research Activity Start-up
    2009 - 2010
    KOMEYAMA Kazuyoshi; TAKAGI Tsutomu; TORISAWA SHINSUKE; SUZUKI Katsuya; KADOTA MINORU
    To examine responses to environment changes, we monitored the behavior of cultivated Pacific bluefin tuna in a submerged aquaculture net cage. We confirmed notable changes in the swimming depth of fish when cold water was added to the aquaculture net cage. Additionally, we successfully measured the three dimensional swimming path of the fish. This will enable us to evaluate which factors (i.e., a change in the living space of the submerged net cage by upward or downward movement or a decreased volume caused by ocean currents) affect the behavior of the fish by reconstructing their swimming paths.
    Japan Society for the Promotion of Science, Grant-in-Aid for Research Activity Start-up, Kagoshima University, 21880047
  • Swimming performance of the bluefin tuna: Research with an integrated biomechanics-and biotelemetry-based approach
    Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    2006 - 2007
    TAKAGI Tsutomu; KAWABE Ryo; MITSUNAGA Yasushi; UENO Kimihiko
    The purpose of this study is to elucidate the morphology, activity, and swimming mechanism of the bluefin tuna by using an integrated biomechanical-and biotelemetry-based approach. The fluid dynamic properties of bluefin tuna were estimated by computational fluid dynamics (CID) analysis. The coefficients of drag on bluefin tuna decrease as the fish grows. The drag during swimming depends on the amplitude of caudal-fin oscillation but not on its frequency. The theoretical results of CID revealed that the fish swims with its head tilted upward during slow cruising in order to maintain mechanical balance with equilibrium state of the moment around its center of gravity. A coupling glide with a large head-tilt angle and upward swimming with a small angle enable the fish to energetically and efficiently cover long distances. These theoretical results were confirmed by field data obtained using a data logger that can record the depth, head-tilt angle, and tail-beating activity of a tuna during swimming. It is believed that the pectoral fin of the bluefin tuna, owing to its negative buoyancy, produces a lift force that supports the submerged weight of the fish. We therefore performed CID analysis to confirm the function of the pectoral fin. For this purpose, we developed a novel data logger that records the movement of the pectoral fin toward or away from the body by using a magnetic sensor. The recorded data revealed that the fish often extends its fin during slow swimming in order to produce the required lift force. To estimate the efficiency at which metabolic energy is converted to external work during swimming, we performed experiments using a water tunnel. The cost of transport (COT) for a young bluefin tuna is approximately 15000 J・kg^<-1>・km^<-1>. However, on the basis of the CFD analysis, we estimated the external work for swimming to be 2-4% of the COT; this suggests that the bluefin tuna can use most of its metabolic energy to maintain its body temperature.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Kinki University, 18580195
  • クロマグロの遊泳能力と群行動メカニズムに関する研究
    2003 - 2007
    Competitive research funding
  • 旋網漁具の網形状数値シミュレーションと最適操業システムの構築
    委託研究
    2004 - 2006
    Competitive research funding
  • クロマグロ等魚類養殖施設の最適構造の検討
    2003 - 2004
    Competitive research funding
  • 網漁具の形状と運動に関する数値シミュレーション手法の開発
    科学研究費助成事業 奨励研究(A)
    2001 - 2002
    高木 力
    昨年度,網地の形状と運動を推定する数値計算用モデルを開発し試計算を行った。その結果,網形状は実測値と計算値で非常によく一致した。本年度は以下にあげる成果を得ることができた。
    ■計算モデルに内在する問題点を把握するため,水槽実験により複数箇所の網糸に作用する荷重を測定し,計算値と比較した。その結果計算値はいずれの条件でも実測値よりも過小に推定された。この原因は網地に作用する抗力係数を一定として取り扱っていたことに起因していた。水槽実験時の網糸に対するレイノルズ数範囲ではCd値は流速の違いによって大きく変化する遷移域であった。そこでCd値をレイノルズ数の関数として与え,試計算したところ実測値と計算値は非常によく一致し,計算モデルの精度向上をはかることができた。
    ■計算モデルは網地の結節部と脚部を質点としてこれらの運動方程式を連立して解いている。そのため大規模な網地では計算時間の増加は避けられない。そこで効率的な計算を行うため複数の目合をグループ化して計算質点数を減少させることを試みた。その結果10000質点の網地について4目をグループ化した場合,計算精度にほとんど影響を与えることはなく,計算時間は約1/8に減少させることができた。
    ■算定結果の視覚化についてはグラフィックライブラリOpenGLを利用してより詳細かつ効率的に3次元表示が可能となった。これによって市販のグラフィクスアプリケーションソフトに依存することはなくなり,解析システムの開発がより柔軟に行えるようになった。
    本研究で,網漁具形状をコンピュータによって推定する計算モデルを開発することができた。このモデルは定式化も容易なため応用性が高い。一連の研究成果から汎用性のある網地の形状・荷重を推定するシステムが実用化できる可能性は極めて高くなったといえる。今後は実際の網漁具に応用できるように最終的なシステムの完成を目指す。
    日本学術振興会, 奨励研究(A), 近畿大学, 12760135
  • 魚類遊泳時のアクアバイオメカニズムに関する研究
    2002
    Competitive research funding
  • Hydromechanical study of swim-and-glide behaviour on free-ranging flatfish
    Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    2000 - 2001
    NASHIMOTO Katsuaki; TAKAGI Tsutomu; HIRAISHI Tomonori; NAITO Yasuhiko
    Intermittent swimming behaviour of marine fish with negative buoyancy, such as swim-glide behaviour, has been hypothesized to result in a saving of energy required for locomotion between two points. However, there have been no studies that tried to prove this hypothesis in the wild. This has been due in part to the difficulty of observing and monitoring free-ranging fish in the open sea. Previous conventional tagging experiments have indicated that Japanese flounder, Paralichthys olivaceus, sometimes migrated in the far distance, recaptured 1,000 km from the point of release, despite their lower swimming ability and morphological feature without swim bladder.
    In order to measure energetic cost of free-ranging flatfish during migration, it is important to know the activity and time budgets of flatfish on its migration route. Using a depth and acceleration data-logger on Japanese flounders, we obtained continuous record of swimming speed, depth, tailbeat activity and swimming angle of free-ranging flounders, simultaneously. We estimated and compared the migrating energy costs during continuous swim and swim-glide.
    We were successful in direct measurement of swim-glide behaviour from flatfish using tailbeat profiles recorded by the logger for the first time. Compared the migration cost between continuous swim and swim-glide, covering similar distance, migration by adopting swim-glide technique resulted in a 22.3% reduction in number of tailbeats. Thus, this energy-saving strategy allows flatfish with negative buoyancy to migrate the long-distance.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), HOKKAIDO UNIVERSITY, 12660157
  • 定置網内の魚群行動モデル
    2001
    Competitive research funding
  • Numerical model of fish schooling behavior in a set net
    Competitive research funding
  • Study on hydrodynamic characteristics of local water around oceanic life from the viewpoint of marine production
    Competitive research funding
  • Study on net-avoidance of microplankton with quantitative sampling gear
    Competitive research funding
  • Study on calculation of dynamic response of reticulate structure and evaluating its dynamics characteristics
    Competitive research funding
■ Industrial Property Rights
  • 網地形状シミュレーションプログラム,漁網シミュレーションプログラム, 漁撈シミュレーションプログラム並びに漁撈コントロールシステム 特許第3870359号
    Patent right, 髙木 力
    特許3870359

Research Profiles

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