2021 Fiscal Year Final Research Report
Elucidation of acoustic characteristics of the "floating pointhead flounder" by field and tank experiments and realization of acoustic survey of fisheries resources
| Project/Area Number |
19K06201
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 40030:Aquatic bioproduction science-related
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| Research Institution | Hokkaido University |
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Principal Investigator |
MUKAI Tohru 北海道大学, 水産科学研究院, 教授 (60209971)
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| Co-Investigator(Kenkyū-buntansha) |
山本 潤 北海道大学, 北方生物圏フィールド科学センター, 助教 (10292004)
長谷川 浩平 北海道大学, 水産科学研究院, 助教 (30826558)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 魚群探知機 / 音響散乱特性 / 音響資源調査 / 無鰾魚 / ソウハチ |
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| Outline of Final Research Achievements |
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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| Free Research Field |
水産音響学
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| Academic Significance and Societal Importance of the Research Achievements |
カレイ類の現存量の推定は，着底トロールや刺網などによって行われているが，本研究の成果を用いると音響手法によるソウハチの現存量推定が可能となる。さらに，“浮きソウハチ”の時期の春期には，水産重要種とされるスケトウダラ太平洋系群の稚魚が噴火湾から北海道東部沖へと移動する。この移動の際に多くのスケトウダラ稚魚がソウハチと遭遇し捕食されていると推測している。スケトウダラの資源変動は，捕食圧によるところが大きいことが知られており，ソウハチおよびスケトウダラ稚魚の音響調査を行うことで，ソウハチとスケトウダラ稚魚との遭遇の規模・頻度やソウハチの捕食によるスケトウダラ稚魚へのインパクトを評価できると考える。
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