Tilt Angle and Theoretical Target Strength of the Japanese Sandeel, <i>Ammodytes personatus</i>, Captured on the Northern Coast of Hokkaido
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- SAFRUDDIN
- Graduate School of Fisheries Sciences, Hokkaido University
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- KAWAUCHI Yohei
- Graduate School of Environmental Sciences, Hokkaido University
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- ITO Yusuke
- Forestry and Fisheries Dependence, Hiroshima Agriculture
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- MINAMI Kenji
- Faculty of Fisheries Sciences, Hokkaido University
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- ITAYA Kazuhiko
- Wakkanai Fisheries Research Institute, Hokkaido Research Organization
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- MAEDA Keiji
- Wakkanai Fisheries Research Institute, Hokkaido Research Organization
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- MATSUKURA Ryuichi
- Japan Sea National Fisheries Research Institute, Fisheries Research Agency
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- ABE Koki
- National Research Institute of Fisheries Engineering, Fisheries Research Agency
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- YASUMA Hiroki
- Graduate School of Fisheries Sciences, Hokkaido University
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- MIYASHITA Kazushi
- Field Science Center for the Northern Biosphere, Hokkaido University
Bibliographic Information
- Other Title
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- Tilt Angle and Theoretical Target Strength of the Japanese Sandeel, Ammodytes personatus, Captured on the Northern Coast of Hokkaido
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Abstract
The tilt angle, i.e., the angle from horizontal made by the fish body as its head dives down or up, affects the readings on fish echo soundings. We measured the tilt angle of Japanese sandeels (Ammodytes personatus Girard) in a water tank, and calculated the acoustic target strength (TS) using a theoretical scattering model. This study examined the TS of sandeels from the northern coast of Hokkaido, which have a larger body size than those in other regions in Japan. TS values for sandeels, a swimbladderless fish, were estimated using a distorted-wave Born approximation (DWBA) model at two frequencies: 38 and 120 kHz. The mean tilt angle was 20.4° (S.D.=18.5°), which differed slightly from that of the lesser sandeel, Ammodytes marinus. The regression equations of the average TS values were TS38kHz=8.2 log10SL−74.2 and TS120kHz=20.9 log10 SL−92.6, respectively. At 120 kHz, the slope was close to 20, suggesting that the acoustic backscattering strength was proportional to the square of the body length. This value was smaller at 38 kHz, suggesting that the acoustic backscattering strength was stable to differences in body length. We obtained a small discrepancy for both frequencies (ΔTS=TS120kHz−TS38kHz) were TS120kHz<TS38kHz. Discrepancies of −1.3 dB for the maximum TS, and −1.8 dB for averaged TS were found in 72 fish samples, which would be useful for identifying sandeel schools in practical analysis using TS differences.
Journal
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- The Journal of the Marine Acoustics Society of Japan
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The Journal of the Marine Acoustics Society of Japan 40 (4), 329-338, 2013
The Marine Acoustics Society of Japan
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Details 詳細情報について
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- CRID
- 1390001204366045568
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- NII Article ID
- 130005116096
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- NII Book ID
- AN10299394
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- ISSN
- 18816819
- 09165835
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- NDL BIB ID
- 024931472
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- Text Lang
- en
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed