Search Results - "Amakasu, Kazuo"

Seasonal dynamics of zooplankton in the southern Chukchi Sea revealed from acoustic backscattering strength by Kitamura, Minoru, Amakasu, Kazuo, Kikuchi, Takashi, Nishino, Shigeto

“…To understand the seasonal dynamics of zooplankton in the southern Chukchi Sea, we use observations from a moored multi-frequency echo-sounder from July 2012…”
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A broadband target strength measurement method for weakly scattering animals using a 50-ms-long linear frequency modulated signal in a small tank by Saygili, Burak, Tsuyuki, Soma, Liu, Jing, Yamamoto, Natsuki, Kobayashi, Kenichi, Amakasu, Kazuo

“…We built a new pulse-echo system using a small tank (1 × 1 × 1 m) for measuring the broadband target strength of weakly scattering animals such as krill and…”
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Effects of fast Fourier transform window size on the target strength spectra of tungsten carbide spheres by Liu, Jing, Saygili, Burak, Iwasa, Akira, Yamamoto, Natsuki, Imaizumi, Tomohito, Amakasu, Kazuo

“…The window size (WS) of the fast Fourier transform (FFT) is one of the important parameters when calculating target strength (TS) spectra from broadband echo…”
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Annual variation of oceanographic conditions changed migration timing of bowhead whales Balaena mysticetus in the southern Chukchi Sea by Tsujii, Koki, Otsuki, Mayuko, Akamatsu, Tomonari, Amakasu, Kazuo, Kitamura, Minoru, Kikuchi, Takashi, Fujiwara, Amane, Shirakawa, Hokuto, Miyashita, Kazushi, Mitani, Yoko

“…The Chukchi Sea environment changes considerably in physical and biological conditions, driven by the expanding volume of warm Pacific summer water. These…”
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Possible fluid discharge associated with faults observed by a high-resolution dense-2D seismic reflection survey in Uchiura Bay off Numazu, Japan by Tsuru, Tetsuro, Park, Jin-Oh, Amakasu, Kazuo, No, Tetsuo, Arai, Kohsaku, Inoue, Takahiko, Furuyama, Seishiro, Uchida, Keiichi, Nakamura, Yasuyuki

“…Although fluid behavior along faults has often been associated with earthquakes and hydrocarbon accumulation, few observations of active, ongoing fluid…”
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Volume backscattering spectra measurements of Antarctic krill using a broadband echosounder by Yamamoto, Natsuki, Amakasu, Kazuo, Abe, Koki, Matsukura, Ryuichi, Imaizumi, Tomohito, Matsuura, Tomohiko, Murase, Hiroto

“…For the acoustic inference of lengths and orientation angles of Antarctic krill (krill), reliable theoretical acoustic scattering models and parameters are…”
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A new seismic survey technology using underwater speaker detected a low-velocity zone near the seafloor: an implication of methane gas accumulation in Tokyo Bay by Tsuru, Tetsuro, Amakasu, Kazuo, Park, Jin-Oh, Sakakibara, Junichi, Takanashi, Mamoru

“…Owing to the strict restrictions on the use of air guns in marine seismic surveys due to concerns about their potential impact on the marine ecosystem, there…”
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Distributions of larval and juvenile/adult stages of the Antarctic myctophid fish, Electrona antarctica, off Wilkes Land in East Antarctica by Moteki, Masato, Fujii, Kentaro, Amakasu, Kazuo, Shimada, Keishi, Tanimura, Atsushi, Odate, Tsuneo

“…Myctophid fish are an important component of the Southern Ocean food web because of their very high biomass. This study investigated the spatial distributions…”
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The analysis of echotrace obtained by a split-beam echosounder to observe the tilt-angle dependence of fish target strength in situ by Furusawa, Masahiko, Amakasu, Kazuo

“…Furusawa, M., and Amakusu, K. 2010. The analysis of echotrace obtained by a split-beam echosounder to observe the tilt-angle dependence of fish target strength…”
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Estimation of target strength of Sardina pilchardus and Sardinella aurita by theoretical approach by Ayoubi, Salaheddine El, Mamza, Kamal, Fujino, Tadanori, Abe, Koki, Amakasu, Kazuo, Miyashita, Kazushi

“…The target strength (TS) patterns of Sardina pilchardus and Sardinella aurita at 38 and 120 kHz were estimated by a prolate-spheroid model, using measurements…”
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Acoustic scattering measurements by an ultra-broadband transducer using multilayer piezoelectric elements by Amakasu, Kazuo, Mishima, Yuka, Mukai, Tohru, Sawada, Kouichi, Sasakura, Toyoki

“…A Langevin-type broadband transducer has been built using multilayer piezoelectric elements. The resonance frequency of this element was 138 kHz, but the…”
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Pelagic fish distribution and ontogenetic vertical migration in common mesopelagic species off Lützow-Holm Bay (Indian Ocean sector, Southern Ocean) during austral summer by Moteki, Masato, Horimoto, Naho, Nagaiwa, Riou, Amakasu, Kazuo, Ishimaru, Takashi, Yamaguchi, Yukuya

“…The horizontal and vertical distributions of fish were examined off Lützow-Holm Bay in the Indian Ocean sector of the Southern Ocean during midnight sun in…”
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Distribution and density of Antarctic krill ( Euphausia superba) and ice krill ( E. crystallorophias) off Adélie Land in austral summer 2008 estimated by acoustical methods by Amakasu, Kazuo, Ono, Atsushi, Hirano, Daisuke, Moteki, Masato, Ishimaru, Takashi

“…From January to February 2008 the training research vessel TRV Umitaka Maru conducted a comprehensive oceanographic survey of the waters around the 140°E…”
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Basin-scale distribution pattern and biomass estimation of Japanese anchovy Engraulis japonicus in the western North Pacific by Murase, Hiroto, Kawabata, Atsushi, Kubota, Hiroshi, Nakagami, Masayasu, Amakasu, Kazuo, Abe, Koki, Miyashita, Kazushi, Oozeki, Yoshioki

“…The distribution pattern and biomass of the Japanese anchovy Engraulis japonicus in the offshore region of the western North Pacific (north of 35°N and west of…”
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Sexual dimorphism in body shape of Antarctic krill ( Euphausia superba) and its influence on target strength by Amakasu, Kazuo, Ono, Atsushi, Moteki, Masato, Ishimaru, Takashi

“…Sexual dimorphism in the body shape of Antarctic krill ( Euphausia superba) was investigated and its influence on target strength (TS) was clarified using a…”
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The target strength of Antarctic krill (Euphausia superba) measured by the split-beam method in a small tank at 70 kHz by Amakasu, Kazuo, Furusawa, Masahiko

“…The target strengths (TS) of Antarctic krill (Euphausia superba) were measured at 70 kHz aboard the research and training vessel “Umitaka-maru” of Tokyo…”
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Euphausiid community structure and population structure of Euphausia superba off Adélie Land in the Southern Ocean during austral summer 2003, 2005 and 2008 by Ono, Atsushi, Moteki, Masato, Amakasu, Kazuo, Toda, Ryoji, Horimoto, Naho, Hirano, Daisuke, Ishimaru, Takashi, Hosie, Graham W.

“…The distribution and community structure of euphausiids and the population structure of Euphausia superba were investigated mainly along 140°E off Adélie Land…”
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Multilayer biological structure and mixing in the upper water column of Lake Biwa during summer 2008 by Yamazaki, Hidekatsu, Honma, Hikaru, Nagai, Takeyoshi, Doubell, Mark J, Amakasu, Kazuo, Kumagai, Michio

“…We carried out a 24-h station experiment at Lake Biwa (Japan) to measure mixing events and concurrent biological signals using a free-fall microstructure…”
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Target strength pattern measurement of krill ( Euphausia   pacifica ) and measuring limits in a small tank by Sawada, Kouichi, Mukai, Tohru, Amakasu, Kazuo, Abe, Koki, Ishii, Ken

“…Euphausia pacifica is an extremely important species for Japanfs northeast coastal fisheries and a key species for ecosystems in the northwest Pacific Ocean…”
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Comparison of the volume backscattering strength measured by EK60 and EK80 by Mukai, Tohru, Amakasu, Kazuo

“…Walleye pollack (Gadus chalcogrammus) resources are abundant around Hokkaido in Japan. The acoustic survey of the walleye pollack using the quantitative…”
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