2025/06/22 更新

写真a

アカマツ トモナリ
赤松 友成
所属
研究院(研究機関) ナノ・ライフ創新研究機構
職名
上級研究員(研究院教授)
学位
博士(農学) ( 1996年03月 日本大学 )
メールアドレス
メールアドレス
プロフィール

早稲田大学 ナノ・ライフ創新研究機構 研究院教授。専門は水中生物音響学。1989年東北大学大学院理学研究科修士課程修了、博士(農学)(日本大学1996年)。水産庁水産工学研究所、国立極地研究所客員研究員、ケンタッキー大学生物科学科客員研究員、公益財団法人笹川平和財団 海洋政策研究所 海洋政策研究部長 / 上席研究員などを経て、2024年より現職。専門は生物音響学、海洋音響学、海産哺乳類学。国際標準化機構TC43技術委員会委員、国際自然保護連合鯨類専門家委員および同海牛類専門家委員、環境影響審査助言委員ほか多数。

学歴

  • 1987年04月
    -
    1989年03月

    東北大学   大学院理学研究科   物理学科  

  • 1983年04月
    -
    1987年03月

    東北大学   理学部   物理学科  

  • 1980年04月
    -
    1983年03月

    静岡県立韮山高校  

委員歴

  • 2025年04月
    -
    継続中

    海洋音響学会  副会長

  • 2025年04月
    -
    継続中

    海洋理工学会  理事

  • 2021年
    -
    継続中

    文部科学省「海洋生物ビッグデータ活用技術高度化」事業  外部評価委員会 委員(主査)

  • 2019年
    -
    継続中

    海産哺乳類学会(Nominations and Elections Committee)

  • 2019年
    -
    継続中

    米音響学会 (Technical committee of Animal Bioacoustics)

  • 2015年
    -
    継続中

    海洋音響学会(理事・企画運営委員)

  • 2013年
    -
    継続中

    IUCN(国際自然保護連合)海牛類専門家委員

  • 2011年
    -
    継続中

    ISO(国際標準化機構)技術委員会43音響分野委員

  • 2008年
    -
    継続中

    アジア水産音響学会  理事

  • 2008年
    -
    継続中

    IUCN(国際自然保護連合)鯨類専門家委員

  • 2025年01月
    -
    2027年12月

    米国電気電子学会 / 海洋工学協会  卓越講演者

  • 2025年
    -
    2027年

    米国電気電子学会 海洋工学会 優良講師

  • 2015年
    -
    2024年

    環境影響審査助言委員

  • 2022年
    -
    2023年

    東京海洋大学海洋AIコンソーシアム  運営協議会委員

  • 2022年
    -
    2023年

    内閣府受託事業「我が国が戦略的に推し進めるべき安全・安心の確保に係る重要技術等の検討業務」  委員

  • 2020年
    -
    2022年

    国立研究開発法人 水産研究・教育機構  客員研究員

  • 2020年
    -
    2021年

    日本学術振興会  書面審査委員

  • 2017年
    -
     

    科学研究費補助金合議審査委員 基盤C・若手

  • 2016年
    -
     

    NEDO洋上風力発電等技術研究開発委員会委員

  • 2015年
    -
     

    環境省 洋上風力発電所等に係る環境影響評価の基本的な考え方に関する検討会委員

  • 2014年
    -
     

    環境省 平成26年度潮流発電技術実用化推進事業委員会委員

  • 2014年
    -
     

    NEDO 海洋洋エネルギー技術研究開発/ 次世代海洋エネルギー発電技術研究開発/ 着定式潮流発電委員会委員

  • 2014年
    -
     

    環境省 環境アセスメント調査早期実施実証事業ステアリング委員会

  • 2013年
    -
     

    海洋音響学会企画運営委員会委員

  • 2013年
    -
     

    科学研究費補助金書面審査委員 基盤・若手

  • 2013年
    -
     

    農林水産省が新たに行う競争的資金事業の書類審査専門委員

  • 2013年
    -
     

    環境省 個別事業助言委員

  • 2013年
    -
     

    浮体式洋上風力発電機設置実証事業 海鳥及び海生生物等の保全検討委員

  • 2013年
    -
     

    経済産業省洋上風力発電等技術研究開発委員

  • 2012年
    -
     

    文部科学省科学技術政策研究所科学技術動向研究センター専門調査員

  • 2012年
    -
     

    環境省風力発電等環境アセスメント基礎情報整備モデル事業検討会委員

  • 2012年
    -
     

    環境省風力発電等環境アセスメント先行実施モデル事業検討会委員

  • 2010年
    -
     

    海洋研究開発機構海洋工学センター評価助言委員

  • 2010年
    -
     

    洋上ウィンドファーム事業性評価手法検討委員

  • 2009年
    -
     

    第5回生物ソナー国際シンポジウム組織委員

  • 2006年
    -
     

    日米音響学会ジョイントミーティング組織委員

▼全件表示

所属学協会

  •  
     
     

    米国音響学会

  •  
     
     

    日本動物行動学会

  •  
     
     

    日本水産学会

  •  
     
     

    日本音響学会

  •  
     
     

    海洋音響学会

  •  
     
     

    SMM(海産哺乳類学会)

  •  
     
     

    Acoustical Society of America

  •  
     
     

    Society for Marine Mammalogy

▼全件表示

研究分野

  • 水圏生産科学 / 生態学、環境学

研究キーワード

  • 海洋政策

  • 水中騒音

  • 環境影響評価

  • 洋上風力発電

  • 魚の聴覚

  • 超音波

  • 水中生物音響

  • エコーロケーション

  • 生物ソナー

▼全件表示

受賞

  • 海洋音響学会論文賞

    2015年  

  • 日本水産学会進歩賞

    2015年  

  • JAMSTEC中西賞

    2009年  

  • 日本水産学会論文賞

    2008年03月   日本水産学会  

  • 海洋音響学会論文賞

    2001年  

 

論文

  • Biologging as a potential platform for resolving ocean environmental issues and threats: Towards the development of the Internet of Animals

    Takashi Iwata, Tomonari Akamatsu

    Water Biology and Security     100383 - 100383  2025年03月

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Development of a coping plan based on Scenario Planning theory – from safety to Security

    Yuki Kobayashi, Tomonari Akamatsu

    Nippon Suisan Gakkaishi (Japanese Edition)   90 ( 6 ) 558  2024年11月

    DOI

    Scopus

  • Temporal and spatial biosonar activity of the recently established uppermost Yangtze finless porpoise population downstream of the Gezhouba Dam: Correlation with hydropower cascade development, shipping, hydrological regime, and light intensity.

    Zhi-Tao Wang, Peng-Xiang Duan, Tomonari Akamatsu, Ke-Xiong Wang, Ding Wang

    Ecology and evolution   14 ( 5 ) e11346  2024年05月  [国際誌]

     概要を見る

    Numerous dams disrupt freshwater animals. The uppermost population of the critically endangered Yangtze finless porpoise has been newly formed below the Gezhouba Dam, however, information regarding the local porpoise is scarce. Passive acoustic monitoring was used to detect the behaviors of porpoises below the Gezhouba Dam. The influence of shipping, pandemic lockdown, hydrological regime, and light intensity on the biosonar activity of dolphins was also examined using Generalized linear models. Over the course of 4 years (2019-2022), approximately 848, 596, and 676 effective monitoring days were investigated at the three sites, from upstream to downstream. Observations revealed significant spatio-temporal biosonar activity. Proportion of days that are porpoise positive were 73%, 54%, and 61%, while porpoise buzz signals accounted for 78.49%, 62.35%, and 81.30% of all porpoise biosonar at the three stations. The biosonar activity of porpoises was much higher at the confluence area, particularly at the MZ site, during the absence of boat traffic, and during the Pandemic shutdown. Temporal trends of monthly, seasonal, and yearly variation were also visible, with the highest number of porpoises biosonar detected in the summer season and in 2020. Significant correlations also exist between the hydrological regime and light intensity and porpoise activity, with much higher detections during nighttime and full moon periods. Hydropower cascade development, establishment of a natural reserve, fish release initiatives, and implementation of fishing restrictions may facilitate the proliferation of the porpoise population downstream of the Gezhouba Dam within the Yichang section of the Yangtze River. Prioritizing restoration designs that match natural flow regimes, optimize boat traffic, and reduce noise pollution is crucial for promoting the conservation of the local porpoises.

    DOI PubMed

    Scopus

    2
    被引用数
    (Scopus)
  • Increased Yangtze finless porpoise presence in urban Wuhan waters of the Yangtze River during fishing closures

    Zhi Tao Wang, Peng Xiang Duan, Tomonari Akamatsu, Ke Xiong Wang, Ding Wang

    Ecology and Evolution   14 ( 4 )  2024年04月

     概要を見る

    Wuhan, a highly urbanized and rapidly growing region within China's Yangtze Economic Zone, has historically been identified as a gap area for the critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) based on daytime visual surveys. However, there has been a noticeable increase in porpoise sightings since 2020. This study employed passive acoustic monitoring to investigate porpoise distribution in Wuhan between 2020 and 2022. Generalized linear models were used to explore the relationship between shipping, hydrological patterns, light intensity, and porpoise biosonar activity. Over 603 days of effective monitoring, the daily positive rate for porpoise biosonar detection reached 43%, with feeding-related buzz signals accounting for 55% of all porpoise biosonar signals. However, the proportion of minutes during which porpoise presence was detected was 0.18%, suggesting that while porpoises may frequent the area, their visits were brief and mainly focused on feeding. A significant temporal trend emerged, showing higher porpoise biosonar detection during winter (especially in February) and 2022. Additionally, periods without boat traffic correlated with increased porpoise activity. Hydrological conditions and light levels exhibited significant negative correlations with porpoise activity. Specifically, porpoise sonar detections were notably higher during the night, twilight, and new moon phases. It is highly conceivable that both fishing bans and COVID-19 pandemic-related lockdowns contributed to the heightened presence of porpoises in Wuhan. The rapid development of municipal transportation and shipping in Wuhan and resulting underwater noise pollution have emerged as a significant threat to the local porpoise population. Accordingly, it is imperative for regulatory bodies to effectively address this environmental stressor and formulate targeted protection measures to ensure the conservation of the finless porpoise.

    DOI

    Scopus

    5
    被引用数
    (Scopus)
  • Fine-scale spatial variability of marine acoustic environment corresponds with habitat utilization of Indo-Pacific humpback dolphins in Hong Kong waters

    Yuen Wa Ho, Tzu Hao Lin, Tomonari Akamatsu, Leszek Karczmarski

    Ecological Indicators   158  2024年01月

     概要を見る

    Acoustic properties of the underwater environment are important in maintaining biological processes of various marine organisms. However, with the increasing level of underwater noise in the global ocean, there is a growing need to better understand how marine animals use soundscape cues in their habitat selection. Indo-Pacific humpback dolphins (Sousa chinensis) inhabiting the Pearl River Estuary, southeast China, live in one of world's most developed and noisiest coastal environment and are subjected to many sources of anthropogenic noise. To investigate whether spatial variability of underwater soundscape corresponds with their habitat utilization, we collected daytime underwater recordings in western Hong Kong waters from mid-2016 to mid-2018, and quantified the spatial pattern of marine acoustic environment and its differing characteristics in a fine spatial scale. We developed a framework of soundscape information retrieval to investigate spectral features that may facilitate identification of dolphins’ core habitats. Our findings reveal that a spectral feature, which peaks at 2 kHz, is a reliable predictor of humpback dolphin core habitat. Further modelling of spatial and seasonal variations of underwater soundscape demonstrates that the relative strength of this spectral feature is positively correlated with the sighting rates of humpback dolphins throughout the year. Although the source of the 2 kHz feature remains unknown, it is likely associated with humpback dolphins’ prey. We suggest that underwater acoustic environment represents an important component in evaluating the quality and suitability of coastal habitats for the daily needs of this threatened dolphin species. Local and regional conservation authorities should include habitat-specific baseline soundscape data when developing conservation management strategies.

    DOI

    Scopus

    6
    被引用数
    (Scopus)
  • Spatiotemporal variations in the acoustic presence of dugongs and vessel traffic around Talibong Island, Thailand: Inputs for local coastal management from passive acoustical aspects

    Kotaro Tanaka, Kotaro Ichikawa, Tomonari Akamatsu, Kongkiat Kittiwattanawong, Nobuaki Arai, Hiromichi Mitamura

    Ocean and Coastal Management   245  2023年11月

     概要を見る

    Examining the spatiotemporal habitat use by marine megafauna and human activities at a fine scale is important to achieve harmonised management of coastal areas. Passive acoustic monitoring (PAM) can provide this information by observing animal vocalisations and the sounds generated by motorised vessels. Dugongs (Dugong dugon), which are endangered herbivorous mammals inhabiting coastal seas, communicate through social calls. Although their spatiotemporal acoustic presence on a fine scale could assist in prioritizing local marine spatial planning, such knowledge is limited. To address this gap, we examined the spatiotemporal pattern of the acoustic presence of dugongs and its correlation with environmental and anthropological factors; additionally, the overlap of these areas with vessel traffic was illustrated. Underwater recorders were deployed at 11 locations around Talibong Island, Thailand, for one month in both rainy and dry seasons. Based on the recorded sound stream, dugong calls and vessel sounds were automatically detected using custom-made software, and false detections were removed by manual examinations. In 2019 and 2020, 1933 h and 2719 h of recordings, respectively, revealed that while dugongs had a clear spatial preference for vocal communication at some locations, their temporal patterns varied among locations. Further, their acoustic presence was significantly correlated with environmental and anthropological factors at some locations, while these factors varied among other locations. However, the distribution of vessel traffic was spatially and temporally stable. These results suggested that (1) spatial management of vocalisation areas can effectively conserve dugongs by protecting their social behaviour and (2) temporal planning may reduce the potential disturbance risk to dugongs. Moreover, to achieve harmonised marine spatial planning in coastal areas, the PAM approach for social calls can be effectively employed to provide a unique layer of habitat use for vocalising species and vessel traffic on a fine scale.

    DOI

    Scopus

    4
    被引用数
    (Scopus)
  • Visualizing the annual transition of ocean policy in Japan using text mining

    Mengyao Zhu, Kotaro Tanaka, Tomonari Akamatsu

    Marine Policy   155  2023年09月

     概要を見る

    Research on evidence-based marine policymaking is still immature, especially regarding the utilization of text data. This study visualized the transition of ocean policy in Japan using text mining technique applied to the text data of three annual reports: the Fishery white paper from 2007 to 2020, Environmental white paper from 2008 to 2020, and Ocean white paper from 2004 to 2020. The results of the analysis were compared with the expert interviews on each subject. Based on latent Dirichlet allocation (LDA) topic model analysis, significant differences in topics were observed among these white papers, while they all clearly responded to the Great East Japan Earthquake occurred in 2011 with their unique topics. Major transitions in topics occurred several times over the years for all white papers. For the Fishery white paper and Environmental white paper issued by the government agencies, notable transitions occurred in 2011, 2013, 2017 and 2012, 2018, respectively, which were mainly caused by the revisions of relevant laws; while for the Ocean white paper issued by non-government organization, transitions occurred in 2009 and 2016, which were closely related to the development of worldwide ocean initiatives. The expert interviews revealed that the experts’ views on the topics and the transitions of policy focuses were generally consistent with the unsupervised analysis results. Automated visualization of policy transition in each organization accelerates the extraction of their directions and roles in policymaking which will help provide scientific evidence for identifying future opportunities for inter-organizational collaboration.

    DOI

    Scopus

    8
    被引用数
    (Scopus)
  • Anthropogenic activity, hydrological regime, and light level jointly influence temporal patterns in biosonar activity of the Yangtze finless porpoise at the junction of the Yangtze River and Poyang Lake, China

    Peng Xiang Duan, Zhi Tao Wang, Tomonari Akamatsu, Nick Tregenza, Guang Yu Li, Ke Xiong Wang, Ding Wang

    Zoological Research   44 ( 5 ) 919 - 931  2023年09月

     概要を見る

    Under increasing anthropogenic pressure, species with a previously contiguous distribution across their ranges have been reduced to small fragmented populations. The critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis), once commonly observed in the Yangtze River-Poyang Lake junction, is now rarely seen in the river-lake corridor. In this study, static passive acoustic monitoring techniques were used to detect the biosonar activities of the Yangtze finless porpoise in this unique corridor. Generalized linear models were used to examine the correlation between these activities and anthropogenic impacts from the COVID-19 pandemic lockdown and boat navigation, as well as environmental variables, including hydrological conditions and light levels. Over approximately three consecutive years of monitoring (2020 2022), porpoise biosonar was detected during 93% of logged days, indicating the key role of the corridor for finless porpoise conservation. In addition, porpoise clicks were recorded in 3.80% of minutes, while feeding correlated buzzes were detected in 1.23% of minutes, suggesting the potential existence of localized, small-scale migration. Furthermore, both anthropogenic and environmental variables were significantly correlated with the diel, lunar, monthly, seasonal, and annual variations in porpoise biosonar activities. During the pandemic lockdown period, porpoise sonar detection showed a significant increase. Furthermore, a significant negative correlation was identified between the detection of porpoise click trains and buzzes and boat traffic intensity. In addition to water level and flux, daylight and moonlight exhibited significant correlations with porpoise biosonar activities, with markedly higher detections at night and quarter moon periods. Ensuring the spatiotemporal reduction of anthropogenic activities, implementing vessel speed restrictions (e.g., during porpoise migration and feeding), and maintaining local natural hydrological regimes are critical factors for sustaining porpoise population viability.

    DOI PubMed

    Scopus

    8
    被引用数
    (Scopus)
  • Statistical analysis of measured underwater radiated noise from merchant ships using ship operational and design parameters

    Masahiro Sakai, Reo Haga, Toshio Tsuchiya, Tomonari Akamatsu, Naoya Umeda

    The Journal of the Acoustical Society of America   154 ( 2 ) 1095 - 1105  2023年08月

    DOI PubMed

    Scopus

    5
    被引用数
    (Scopus)
  • Using Soundscapes to Assess Changes in Coral Reef Social-Ecological Systems

    Tzu Hao Lin, Frederic Sinniger, Saki Harii, Tomonari Akamatsu

    Oceanography   36 ( 1 ) 20 - 27  2023年03月

    DOI

    Scopus

    7
    被引用数
    (Scopus)
  • Sound properties produced by white-edged rockfish (Sebastes taczanowskii) in relation to body and swim bladder size

    Naoto Matsubara, Seiji Katakura, Ryuzo Takahashi, Tomonari Akamatsu, Hiroki Yasuma

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   153 ( 3 ) 1703 - 1709  2023年03月

    DOI PubMed

    Scopus

    3
    被引用数
    (Scopus)
  • Marine invertebrates and noise

    Marta Solé, Kenzo Kaifu, T. Aran Mooney, Sophie L. Nedelec, Frédéric Olivier, Andrew N. Radford, Mirella Vazzana, Matthew A. Wale, Jayson M. Semmens, Stephen D. Simpson, Giuseppa Buscaino, Anthony Hawkins, Natacha Aguilar de Soto, Tomoari Akamatsu, Laurent Chauvaud, Ryan D. Day, Quinn Fitzgibbon, Robert D. McCauley, Michel André

    Frontiers in Marine Science   10  2023年

     概要を見る

    Within the set of risk factors that compromise the conservation of marine biodiversity, one of the least understood concerns is the noise produced by human operations at sea and from land. Many aspects of how noise and other forms of energy may impact the natural balance of the oceans are still unstudied. Substantial attention has been devoted in the last decades to determine the sensitivity to noise of marine mammals—especially cetaceans and pinnipeds—and fish because they are known to possess hearing organs. Recent studies have revealed that a wide diversity of invertebrates are also sensitive to sounds, especially via sensory organs whose original function is to allow maintaining equilibrium in the water column and to sense gravity. Marine invertebrates not only represent the largest proportion of marine biomass and are indicators of ocean health but many species also have important socio-economic values. This review presents the current scientific knowledge on invertebrate bioacoustics (sound production, reception, sensitivity), as well as on how marine invertebrates are affected by anthropogenic noises. It also critically revisits the literature to identify gaps that will frame future research investigating the tolerance to noise of marine ecosystems.

    DOI

    Scopus

    55
    被引用数
    (Scopus)
  • Development of edge computing underwater sound recorder to monitor deep sea soundscape

    Masaya Katagiri, Shinsuke Kawagucci, Hiromi Kayama Watanabe, Kotaro Tanaka, Tomonari Akamatsu

    2023 IEEE International Symposium on Underwater Technology, UT 2023    2023年

     概要を見る

    Sound propagates at a greater range than light in marine environments. Anthropogenic sound and noise pollution caused by deep sea mining and offshore wind farms are increasing, which may affect the marine ecosystem. However, sound datasets in oceanic environments are quite limited. In this paper, we summarize the requirements of a deep sea soundscape monitoring device by reviewing currently available instruments, and we propose a cost-effective and noise reductive recording system to the monitor marine soundscape to identify temporal variations in the soundscape at various scales. The development of this system is ongoing, and we summarize the results of two trial deployments in a huge aquarium tank and off the pier of a marine station. The results demonstrate that the noise generated and the battery consumption of the proposed system are comparable to conventional systems. However, the proposed system is highly versatile due to the scalability of the IDE of the system's software. Our work to develop a cost-effective, noise-reductant and long-term recording system will contribute to the acquisition of soundscape data in marine environments, which is expected to enable the identification of baseline sound properties in various marine environments and reconstruct temporal and spatial variations of marine biodiversity and ecosystem dynamics.

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Underwater sound observation using the Edokko Mark i as a platform of acoustic environment assessment for marine mineral resource development

    Yosuke Onishi, Hajime Naganuma, Yuya Yamamoto, Masayuki Nagao, Naoki Saito, Atsushi Suzuki, Kyohei Takami, Mitsuru Shimazu, Tomonari Akamatsu

    2023 IEEE International Symposium on Underwater Technology, UT 2023    2023年

     概要を見る

    group have developed an underwater sound recording device capable of observing underwater sound for approximately one year at a depth of 6,000 meters. We installed this device on the underwater explorer "Edokko Mark I (Type 365),"and obtained intermittent recording for about one year at the research station LE4, located about 160 km offshore south of Minami-Torishima Island, Japan, where marine mineral resources exist. In this study, we report on the newly developed underwater sound recording device and the results of the soundscape analysis.

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Tidal effects on periodical variations in the occurrence of singing humpback whales in coastal waters of Chichijima Island, Ogasawara, Japan

    Koki Tsujii, Tomonari Akamatsu, Ryosuke Okamoto, Kyoichi Mori, Yoko Mitani

    Scientific Reports   12 ( 1 )  2022年11月

    DOI PubMed

    Scopus

    2
    被引用数
    (Scopus)
  • Vocalization of Bryde's whales (Balaenoptera edeni) in the Beibu Gulf, China

    Zhi Tao Wang, Peng Xiang Duan, Mo Chen, Zhi Gang Mei, Xiao Dong Sun, Zhi Wen Nong, Mei Han Liu, Tomonari Akamatsu, Ke Xiong Wang, Ding Wang

    Marine Mammal Science   38 ( 3 ) 1118 - 1139  2022年07月

    DOI

    Scopus

    15
    被引用数
    (Scopus)
  • Spatial distribution maps of real-time ocean observation platforms and sensors in Japanese waters

    Kotaro Tanaka, Mengyao Zhu, Kohei Miyaji, Tadayuki Kurokawa, Tomonari Akamatsu

    Marine Policy   141  2022年07月

    DOI

    Scopus

    3
    被引用数
    (Scopus)
  • エゾメバル(Sebastes taczanowskii)の嗚音の音響特性—Properties of Fish Sound by White-edged Rockfish (Sebastes taczanowskii)

    松原 直人, 齋藤 伶, 赤松 友成, 高橋 竜三, 安間 洋樹

    海洋音響学会誌 = The journal of the Marine Acoustics Society of Japan   49 ( 3 ) 96 - 102  2022年07月

    DOI

  • Auditory evoked potential in stranded melon-headed whales (Peponocephala electra): With severe hearing loss and possibly caused by anthropogenic noise pollution

    Zhi Tao Wang, Alexander Ya Supin, Tomonari Akamatsu, Peng Xiang Duan, Yi Ning Yang, Ke Xiong Wang, Ding Wang

    Ecotoxicology and Environmental Safety   228  2021年12月

    DOI PubMed

    Scopus

    11
    被引用数
    (Scopus)
  • Riverside underwater noise pollution threaten porpoises and fish along the middle and lower reaches of the Yangtze River, China

    Zhi Tao Wang, Peng Xiang Duan, Tomonari Akamatsu, Yu Wei Chen, Xue An, Jing Yuan, Pei Yu Lei, Jiao Li, Lu Zhou, Ming Chao Liu, Yi Ning Yang, Fei Fan, Ke Xiong Wang, Ding Wang

    Ecotoxicology and Environmental Safety   226  2021年12月

    DOI PubMed

    Scopus

    28
    被引用数
    (Scopus)
  • Annual variation of oceanographic conditions changed migration timing of bowhead whales Balaena mysticetus in the southern Chukchi Sea

    Koki Tsujii, Mayuko Otsuki, Tomonari Akamatsu, Kazuo Amakasu, Minoru Kitamura, Takashi Kikuchi, Amane Fujiwara, Hokuto Shirakawa, Kazushi Miyashita, Yoko Mitani

    POLAR BIOLOGY   44 ( 12 ) 2289 - 2298  2021年12月

    DOI

    Scopus

    11
    被引用数
    (Scopus)
  • Baseline soundscapes of deep‐sea habitats reveal heterogeneity among ecosystems and sensitivity to anthropogenic impacts

    Chong Chen, Tzu‐Hao Lin, Hiromi Kayama Watanabe, Tomonari Akamatsu, Shinsuke Kawagucci

    Limnology and Oceanography   66 ( 10 ) 3714 - 3727  2021年10月

    DOI

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    11
    被引用数
    (Scopus)
  • Seasonal and diel changes in cetacean vocalizations monitored by passive acoustic methods in Nemuro Strait adjacent to the Shiretoko World Natural Heritage Site

    Mayuko Otsuki, Tomonari Akamatsu, Takahiro Nobetsu, Yoko Mitani

    MARINE MAMMAL SCIENCE   37 ( 4 ) 1330 - 1340  2021年10月

    DOI

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    1
    被引用数
    (Scopus)
  • Coastal development threatens Datan area supporting greatest fish diversity at Taoyuan Algal Reef, northwestern Taiwan

    Joseph Heard, Wei Chen Tung, Yu De Pei, Tzu Hao Lin, Chien Hsiang Lin, Tomonari Akamatsu, Colin K.C. Wen

    Aquatic Conservation: Marine and Freshwater Ecosystems   31 ( 3 ) 590 - 604  2021年03月

    DOI

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    15
    被引用数
    (Scopus)
  • Sensing ecosystem dynamics via audio source separation: A case study of marine soundscapes off northeastern Taiwan

    Tzu Hao Lin, Tomonari Akamatsu, Yu Tsao

    PLoS Computational Biology   17 ( 2 )  2021年02月

    DOI PubMed

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    13
    被引用数
    (Scopus)
  • Foraging activity of harbour porpoises around a bottom-gillnet in a coastal fishing ground, under the risk of bycatch

    Maeda Saki, Sakurai Kenji, Akamatsu Tomonari, Matsuda Ayaka, Yamamura Orio, Kobayashi Mari, Matsuishi Takashi Fritz

    PLOS ONE   16 ( 2 ) e0246838  2021年02月  [査読有り]  [国際誌]

    DOI PubMed

    Scopus

    5
    被引用数
    (Scopus)
  • Exploring coral reef biodiversity via underwater soundscapes

    Tzu-Hao Lin, Tomonari Akamatsu, Frederic Sinniger, Saki Harii

    Biological Conservation Volume   253   108901  2021年01月  [査読有り]

    DOI

    Scopus

    43
    被引用数
    (Scopus)
  • Automatic detection of dolphin whistles and clicks based on entropy approach

    Shashidhar Siddagangaiah, Chi Fang Chen, Wei Chun Hu, Tomonari Akamatsu, Megan McElligott, Marc O. Lammers, Nadia Pieretti

    Ecological Indicators   117  2020年10月

    DOI

    Scopus

    27
    被引用数
    (Scopus)
  • Passive acoustic monitoring of the distribution patterns of Irrawaddy dolphins (Orcaella brevirostris) in the middle reaches of the Ayeyarwady River, Myanmar

    Zhi Tao Wang, Peng Xiang Duan, Tomonari Akamatsu, Ke Xiong Wang, Ding Wang

    Marine Mammal Science   36 ( 4 ) 1241 - 1253  2020年10月

    DOI

    Scopus

    4
    被引用数
    (Scopus)
  • Underwater noise pollution in China's Yangtze River critically endangers Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis).

    Zhi-Tao Wang, Tomonari Akamatsu, Peng-Xiang Duan, Lu Zhou, Jing Yuan, Jiao Li, Pei-Yu Lei, Yu-Wei Chen, Yi-Ning Yang, Ke-Xiong Wang, Ding Wang

    Environmental pollution (Barking, Essex : 1987)   262   114310 - 114310  2020年07月  [国際誌]

    DOI PubMed

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    54
    被引用数
    (Scopus)
  • Evoked-potential audiogram variability in a group of wild Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis).

    Zhi-Tao Wang, Jiao Li, Peng-Xiang Duan, Zhi-Gang Mei, Fu-Qiang Niu, Tomonari Akamatsu, Pei-Yu Lei, Lu Zhou, Jing Yuan, Yu-Wei Chen, Alexander Ya Supin, Ding Wang, Ke-Xiong Wang

    Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology   206 ( 4 ) 527 - 541  2020年07月  [国際誌]

    DOI PubMed

    Scopus

    20
    被引用数
    (Scopus)
  • Using Soundscapes to Assess Deep-Sea Benthic Ecosystems.

    Tzu-Hao Lin, Chong Chen, Hiromi Kayama Watanabe, Shinsuke Kawagucci, Hiroyuki Yamamoto, Tomonari Akamatsu

    Trends in ecology & evolution   34 ( 12 ) 1066 - 1069  2019年12月  [国際誌]

    DOI PubMed

    Scopus

    27
    被引用数
    (Scopus)
  • Soundscape of an Indo-Pacific humpback dolphin (Sousa chinensis) hotspot before windfarm construction in the Pearl River Estuary, China: Do dolphin engage in noise avoidance and passive eavesdropping behavior?

    Zhi-Tao Wang, Tomonari Akamatsu, Douglas P Nowacek, Jing Yuan, Lu Zhou, Pei-Yu Lei, Jiao Li, Peng-Xiang Duan, Ke-Xiong Wang, Ding Wang

    Marine pollution bulletin   140   509 - 522  2019年03月  [国際誌]

    DOI PubMed

    Scopus

    26
    被引用数
    (Scopus)
  • Leave or stay? Video-logger revealed foraging efficiency of humpback whales under temporal change in prey density.

    Yu Akiyama, Tomonari Akamatsu, Marianne H Rasmussen, Maria R Iversen, Takashi Iwata, Yusuke Goto, Kagari Aoki, Katsufumi Sato

    PloS one   14 ( 2 ) e0211138  2019年  [国際誌]

    DOI PubMed

    Scopus

    13
    被引用数
    (Scopus)
  • Coral reef soundscape to measure the species distribution and biodiversity

    Tomonari Akamatsu, Tzu Hao Lin, Yu Tsao, Frederic Sinniger, Saki Harii

    2018 OCEANS - MTS/IEEE Kobe Techno-Oceans, OCEANS - Kobe 2018    2018年12月

     概要を見る

    Coral reefs represent the most biologically diverse marine ecosystem, however, they are vulnerable to environmental changes and impacts. Therefore, information on the variability of environment and biodiversity is essential for the conservation management of coral reefs. In this study, a soundscape analysis based on range-wide and long-term underwater recording were conducted. Maps of damselfishes and snapping sounds could be obtained by supervised feature extraction of species specific sounds. Using unsupervised classifier, Shannon index of soundscape diversity was shown to be high in deep waters. Mesophotic coral reefs in deep water have been considered as potential refuges for symbiotic corals when coral bleaching happens in shallow reefs due to high sea surface temperature. Results seemed to be consistent with this hypothesis.

    DOI

    Scopus

    7
    被引用数
    (Scopus)
  • Automatic detection of fish sounds based on multi-stage classification including logistic regression via adaptive feature weighting

    Ryosuke Harakawa, Takahiro Ogawa, Miki Haseyama, Tomonari Akamatsu

    The Journal of the Acoustical Society of America   144 ( 5 ) 2709 - 2718  2018年11月

    DOI PubMed

    Scopus

    16
    被引用数
    (Scopus)
  • Change in singing behavior of humpback whales caused by shipping noise

    Tsujii Koki, Akamatsu Tomonari, Okamoto Ryosuke, Mori Kyoichi, Mitani Yoko, Umeda Naoya

    PLOS ONE   13 ( 10 ) e0204112  2018年10月  [査読有り]  [国際誌]

    DOI PubMed

    Scopus

    26
    被引用数
    (Scopus)
  • Automatic detection and localization of croaker’s fish calls using beamforming

    Ikuo Matsuo, Kazuki Yamato, Ryuzo Takahashi, Tomohito Imaizumi, Tomonari Akamatsu

    The Journal of the Acoustical Society of America   144 ( 3 ) 1692 - 1692  2018年09月

    DOI

  • 受動的音響観測による定置網近傍でのネズミイルカの出現と行動

    東坂博樹, 松石隆, 赤松友成

    Fisheries Research   204   269 - 274  2018年08月  [査読有り]

    DOI

    Scopus

    8
    被引用数
    (Scopus)
  • Preliminary report of the diving bahavior "fluke up/down dive" of humpback whales in response to ship noise off Ogasawara (Bonin) Islands, Japan

    Kyoichi Mori, Rina Yamada, Yukino Hirai, Ryosuke Okamoto, Koki Tsuji, Tomonari Akamatsu, Yoko Mitani, Toshio Tsuchiya, Naoya Umeda

    Abstract Book of the 2nd Oceanoise Asia     23  2018年06月

  • Reactions of singing humpback whales to shipping noise in the Ogasawra Islands

    Koki Tsuji, Tomonari Akamatsu, Ryosuke Okamoto, Kyoichi Mori, Yoko Mitani, Naoya Umeda

    Abstract Book of the 2nd Oceanoise Asia     22  2018年06月

  • Comparison of passive acoustic soniferous fish monitoring with supervised and unsupervised approaches

    Tzu Hao Lin, Yu Tsao, Tomonari Akamatsu

    Journal of the Acoustical Society of America   143 ( 4 ) EL278 - EL284  2018年04月

    DOI PubMed

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    31
    被引用数
    (Scopus)
  • Diel changes in ribbon seal Histriophoca fasciata vocalizations during sea ice presence in the Nemuro Strait, Sea of Okhotsk

    Mayuko Otsuki, Tomonari Akamatsu, Takahiro Nobetsu, Daisuke Mizuguchi, Yoko Mitani

    Polar Biology   41 ( 3 ) 451 - 456  2018年03月  [査読有り]

     概要を見る

    Ice-breeding seals use vocal communication mainly during breeding season. The vocal function of aquatic mating, ice-associated ribbon seals (Histriophoca fasciata) has been unknown since they produce sounds in both breeding and non-breeding seasons. We examined the timing of their vocal presence in relation to environmental factors to infer the function of their calls in the Nemuro Strait, northern Japan, since this area is the possible southern limit of their breeding range. Vocalizations of ribbon seals were irregularly sampled from November 2012 to March 2014 in the Nemuro Strait and were compared with sea ice presence, time of day, and tidal currents. Ribbon seal downsweeps were detected in February 2013 and March 2014 only when sea ice was present along the Shiretoko Peninsula in the strait, with more detections in March leading up to the spring breeding season. Downsweep detections decreased in the middle of the day, indicating that ribbon seals were likely to be hauled out during this time. Vocalizing at night and early morning would probably reflect the increased opportunity for attracting females underwater. Our study suggests that the seal vocalizations in concurrence with sea ice presence in the Nemuro Strait could function as underwater communication for breeding.

    DOI

    Scopus

    5
    被引用数
    (Scopus)
  • キツネメバル(Sebastes vulpes)の鳴音の音響特性と威嚇行動に伴う変化

    松原 直人, 松田 裕太, 赤松 友成, 高橋 竜三, 宗原 弘幸, 安間 洋樹

    海洋音響学会誌   45 ( 2 ) 37 - 46  2018年

     概要を見る

    <p>We observed the sound production and properties of fox jacopever (<i>Sebastes vulpes</i>) in a water tank experiment to obtain basic information for the Passive Acoustic Monitoring (PAM). Six pairs of experiments including mature and immature fishes were conducted, and sound properties with and without agonistic behavior were compared. Fox jacopever produced low frequency pulses under 2,000 Hz. Pulse number ranged between 1–77, pulse duration was 0.005–0.220 s, pulse period was 0.001–0.989 s, and peak frequency was 258–490 Hz. These properties were changed by the presence or absence of agonistic behavior. Higher peak frequency over 400 Hz was observed only when a pair included an immature fish. Our results showed the potential use of fish sounds for estimating size and status of territorial behavior in this species by PAM.</p>

    DOI CiNii

  • Tread-water feeding of Bryde's whales

    Takashi Iwata, Tomonari Akamatsu, Surasak Thongsukdee, Phaothep Cherdsukjai, Kanjana Adulyanukosol, Katsufumi Sato

    CURRENT BIOLOGY   27 ( 21 ) R1154 - R1155  2017年11月  [査読有り]

    DOI PubMed

    Scopus

    38
    被引用数
    (Scopus)
  • Silent porpoise: potential sleeping behaviour identified in wild harbour porpoises

    Andrew J. Wright, Tomonari Akamatsu, Kim N. Mouritsen, Signe Sveegaard, Rune Dietz, Jonas Teilmann

    ANIMAL BEHAVIOUR   133   211 - 222  2017年11月  [査読有り]

    DOI

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    21
    被引用数
    (Scopus)
  • ビームフォーミングを利用したニベ科魚類鳴音の自動検知手法

    山登一輝, 松尾行雄, 高橋竜三, 今泉智人, 赤松友成

    海洋音響学会誌   44 ( 4 ) 193‐202 - 202  2017年10月  [査読有り]

    DOI CiNii J-GLOBAL

  • Diversity of fish sound types in the Pearl River Estuary, China

    Zhi-Tao Wang, Douglas P. Nowacek, Tomonari Akamatsu, Ke-Xiong Wang, Jian-Chang Liu, Guo-Qin Duan, Han-Jiang Cao, Ding Wang

    PEERJ   5 ( 10 )  2017年10月  [査読有り]

    DOI

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    17
    被引用数
    (Scopus)
  • Estimation of Direction of Arrival of Fish Calls in a Chorus Using Stereo Hydrophones

    Masanori Ito, Ikuo Matsuo, Tomohito Imaizumi, Tomonari Akamatsu

    MARINE TECHNOLOGY SOCIETY JOURNAL   51 ( 4 ) 68 - 75  2017年07月  [査読有り]

    DOI

    Scopus

  • Evaluation of availability on passive acoustic devices on underwater platforms

    Ryuzo Takahashi, Tomonari Akamatsu, Daisuke Hasegawa, Takeshi Okunishi, Yuya Nishida, Tamaki Ura, Hiroshi Takahashi, Masami Katsuragawa

    Techno-Ocean 2016: Return to the Oceans     317 - 320  2017年03月

     概要を見る

    The noise evaluation of the platform is necessary to use passive acoustic monitoring. In this study, we measured background noise of underwater platforms such as AUVs and deep sea landers. AUV that has thrusters was higher background noise level, when control own position and speed. However, background noise level was deduced, when stopped thrusters. The background noise of AUV of the type of control buoyance of own and of the deep sea lander was low. The background noise of AUVs on low frequency range was higher than high frequency range. A biological sound was observed using AUV. Even if AUV was to depth of the water 900m, the sound of the creature was measured. Therefore, the biological sound could be observed using AUVs or the deep sea lander, and the possibility that the biological sound could be observed automatically and extensively was indicated.

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Acoustic presence of finless porpoises around the Kansai International airport

    Kiyomi Nakamura, Yuji Hirakawa, Naoki Kamezaki, Takashi Nakata, Yusuke Ono, Masaki Hatano, Tomonari Akamatsu

    Techno-Ocean 2016: Return to the Oceans     342 - 345  2017年03月

     概要を見る

    Presence of finless porpoises around Kansai International airport was monitored by a passive acoustic monitoring system. The airport is an artificial land in the ocean and was suggested to create new habitat of marine organisms. Here we showed frequent nocturnal presence of finless porpoises at the south west of the airport where quite limited visual observation data available previously. During 4 months period from December to April in 2016, biosonar sounds of finless porpoises were detected nearly every day. Accumulated number of click trains in one hour time bin were 100 or larger in the nighttime. In contrast, approximately 50 click trains were recorded in the daytime. Ocean engineering newly created an island, Kansai International airport. This structure might create new habitat even for top predators in this water.

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Real time detection and localization system for underwater acoustic signal with cable observatories in the west Pacific Ocean

    Shuhei Nishida, Ryoichi Iwase, Katsuyoshi Kawaguchi, Ikuo Matsuo, Tomonari Akamatsu

    Techno-Ocean 2016: Return to the Oceans     544 - 547  2017年03月

     概要を見る

    A previous research reported that the cable system off Kushiro-Tokachi was detected low frequency calls of fin whales. In this research, as an application using cable observatories about 'development of remote species identification technologies for marine organisms', we developed a real-time processing system for underwater acoustic signal with cable observatory. This paper reports the results of automatically detection and localization from continues observation using hydrophones and seismometers of the cable observatory. The applied system in cable observatories visualizes the number and position of fin whales.

    DOI

    Scopus

    2
    被引用数
    (Scopus)
  • Ocean acoustic observing platforms for marine creatures around Japan

    Tomonari Akamatsu, Ryuzo Takahasi, Tomohito Imaizumi, Katsuyoshi Kawaguchi, Ryoichi Iwase, Shuhei Nishida

    Techno-Ocean 2016: Return to the Oceans     425 - 428  2017年03月

     概要を見る

    Many animals in the ocean produce sounds for mating choice, territorial defending, group cohesion and echolocation. Sound travels much longer distance in the water comparing with light that makes the acoustic waves efficient for long distance communication and sensing. The species or family specific sounds can be used to identify not only the presence of animals but also counting the number and density of target species. In these years, various types of underwater recorders are available. However, for the successful acoustic monitoring in the ocean, safe platforms to deploy the recorders are essential. In this paper, advantages and drawbacks of fixed and mobile platforms for passive acoustic monitoring are summarized referring practical application examples in Japanese waters.

    DOI

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    1
    被引用数
    (Scopus)
  • Long-term effectiveness of pingers on a small population of finless porpoises in Japan

    Masao Amano, Miku Kusumoto, Misaki Abe, Tomonari Akamatsu

    Endangered Species Research   32 ( 1 ) 35 - 40  2017年

    DOI

    Scopus

    19
    被引用数
    (Scopus)
  • Fin whale calls observed with submarine cabled observatories off Kushiro-Tokachi during ten years

    Shuhei Nishida, Ryoichi Iwase, Katsuyoshi Kawaguchi, Ikuo Matsuo, Tomonari Akamatsu

    OCEANS 2016 MTS/IEEE Monterey, OCE 2016    2016年11月

     概要を見る

    In this research, the automatically analyzation method which detect acoustic events such as fin whale calls and its locations is embedded in cable observatory system. This system has detection method about fin whale calls using spectrogram correlation, and the localization of fin whale calls using two hydrophones and a three-axis seismometer. This observation at off Kushiro-Tokachi has been continuously performed for more than 10 years. The detection and tracking analysis for fin whale calls are carried out about the archive data in parallel with the real-time data. The results of the past 10 years including the latest information is reported.

    DOI

    Scopus

  • Acoustic property of sound production by fat greenling (Hexagrammos otakii) in spawning season

    Naoto Matsubara, Hiroyuki Munehara, Ryuzo Takahashi, Tomonari Akamatsu, Kazuki Yamato, Ikuo Matsuo, Nobuo Kimura, Kazuyoshi Maekawa, Hiroki Yasuma

    The Journal of the Acoustical Society of America   140 ( 4 ) 3065 - 3065  2016年10月

    DOI

  • The migration of fin whales into the southern Chukchi Sea as monitored with passive acoustics

    Koki Tsujii, Mayuko Otsuki, Tomonari Akamatsu, Ikuo Matsuo, Kazuo Amakasu, Minoru Kitamura, Takashi Kikuchi, Kazushi Miyashita, Yoko Mitani

    ICES Journal of Marine Science   73 ( 8 ) 2085 - 2092  2016年09月

     概要を見る

    <title>Abstract</title>
    Fin whales (Balaenoptera physalus) undergo seasonal migration in the Arctic Sea. Because their migration and distribution is likely affected by changes in global climate, we aimed to examine the migration timing of fin whales, and the relationship with prey availability within the oceanographic environment of the Arctic Sea, using passive and active acoustic monitoring methods. Automatic Underwater Sound Monitoring Systems were deployed in the southern Chukchi Sea from July 2012 to 2014 to determine the acoustic presence of fin whales. Furthermore, water temperature and salinity were recorded by a fixed data logger. An Acoustic Zooplankton Fish Profiler was additionally deployed to estimate prey abundance through backscattering strength. Sea ice concentrations were obtained by remote sensing data. Fin whale calls were automatically detected using a custom-made software, and the per cent of half-hours containing calls were counted. Fin whale calls were detected from 4 August to 20 October 2012 (78 d) and 25 July to 1 November 2013 (100 d). The extended period of acoustic presence of fin whales during 2013 when compared with 2012 is likely related to a longer ice-free period during 2013. Furthermore, generalized linear model analyses showed that half-hour periods containing calls increased with a rise in water temperature and zooplankton abundance during the initial call presence period, while they decreased with a decrease in water temperature and salinity during the end of the call presence period. Our results suggest that the rise in water temperature and zooplankton abundance affect the timing of migration of fin whales in a way that is consistent with the expansion of their suitable habitats and the extension of their presence in the Arctic Sea.

    DOI

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    22
    被引用数
    (Scopus)
  • ニベ科魚類鳴音の自動抽出法の検討

    宮島(多賀)悠子, 赤松友成, 松尾行雄, 高橋牧, 松崎広和, 新島啓司

    海洋音響学会誌   43 ( 3 ) 116 - 125  2016年07月  [査読有り]

    DOI CiNii

  • Auditory sensitivity in aquatic animals

    Klaus Lucke, Arthur N. Popper, Anthony D. Hawkins, Tomonari Akamatsu, Michel Andre, Brian K. Branstetter, Marc Lammers, Craig A. Radford, Amanda L. Stansbury, T. Aran Mooney

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   139 ( 6 ) 3097 - 3101  2016年06月  [査読有り]

    DOI PubMed

    Scopus

    8
    被引用数
    (Scopus)
  • Apparent source level of free-ranging humpback dolphin, Sousa chinensis, in the South China Sea

    Satoko Kimura, Tomonari Akamatsu, Liang Fang, Zhitao Wang, Kexiong Wang, Ding Wang, Ken Yoda

    JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM   96 ( 4 ) 845 - 851  2016年06月  [査読有り]

    DOI

    Scopus

    17
    被引用数
    (Scopus)
  • Local habitat use by botos (Amazon river dolphins, Inia geoffrensis) using passive acoustic methods

    Yukiko Yamamoto, Tomonari Akamatsu, Vera M.F. da Silva, Shiro Kohshima

    Marine Mammal Science   32 ( 1 ) 220 - 240  2016年01月

    DOI

    Scopus

    9
    被引用数
    (Scopus)
  • キツネメバル(Sebastes vulpes)の行動に伴う 鳴音の特性

    松原 直人, 松田 裕太, 高橋 竜三, 赤松 友成, 宗原 弘幸, 木村 暢夫, 前川 和義, 安間 洋樹

    日本水産工学会 学術講演会 学術講演論文集   2016   133 - 134  2016年

    DOI CiNii

  • 鳴音を用いた小型鯨類の種判別

    亀山 紗穂, 赤松 友成, 荒井 修亮

    海洋理工学会誌   22 ( 1 ) 57 - 61  2016年

     概要を見る

    Passive acoustic monitoring (PAM) has been widely used as the standard method to observe small cetaceans. Recent drastic improvement of monitoring device makes PAM more convenient, cost-effective monitoring method. Also, improvement of analysis methods of acoustic data enables us to estimate habitat range, density, behavior of animals using PAM. However, most previous studies focus on one species and select the data that the observed species were confirmed visually. In order to extend the application of PAM to the field that several species appear simultaneously, species identification method is essential. Especially, PAM plays a key role of environmental assessment on marine development such as offshore wind farm in recent years. In that case, it is important to observe each species which appear in the construction area separately for effective conservation. This paper reviewed the recently developed species identification methods. Basically, many identification methods focused on one of two types of animal call, whistles used for communications or biosonar signals used for echolocation. We introduce the advantage and disadvantage of the method using whistles or biosonar signals, and discuss the current issues and future works we need to resolve them.

    DOI CiNii

  • Migration monitoring of fin whales in the southern Chukchi Sea with acoustic methods during 2012–2015

    Koki Tsujii, Mayuko Otsuki, Tomonari Akamatsu, Ikuo Matsuo, Minoru Kitamura, Takashi Kikuchi, Kazuo Amakasu, Kazushi Miyashita, Yoko Mitani

    2016 Techno-Ocean (Techno-Ocean)   2016   49 - 53  2016年

    DOI

  • Contribution to the Understanding of Particle Motion Perception in Marine Invertebrates

    Michel Andre, Kenzo Kaifu, Marta Sole, Mike van der Schaar, Tomonari Akamatsu, Andreu Balastegui, Antonio M. Sanchez, Joan V. Castell

    EFFECTS OF NOISE ON AQUATIC LIFE II   875   47 - 55  2016年  [査読有り]

    DOI PubMed

    Scopus

    20
    被引用数
    (Scopus)
  • Visualization of fish movement and size estimation of the fish by using broadband split-beam echo sounder

    Tomohito Imaizumi, Koki Abe, Ryuzo Takahashi, Ikuo Matsuo, Tomonari Akamatsu

    TECHNO-OCEAN 2016: RETURN TO THE OCEANS     552 - 555  2016年  [査読有り]

     概要を見る

    It is important information to measure fish movement, swimming direction, and target strength of the fish for species identification by using active acoustics. Broadband quantitative echo sounders have been developed in the world. Broadband system can measure single echo traces from individual fish with high range resolution. Single echo traces with high range resolution give us much more information of fish movements than by using conventional narrow band quantitative echo sounders. This paper presents the results of our in situ measurements.

    DOI

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    1
    被引用数
    (Scopus)
  • Review of Low-Level Bioacoustic Behavior in Wild Cetaceans: Conservation Implications of Possible Sleeping Behavior

    Andrew J. Wright, Tomonari Akamatsu, Kim Norgaard Mouritsen, Signe Sveegaard, Rune Dietz, Jonas Teilmann

    EFFECTS OF NOISE ON AQUATIC LIFE II   875   1251 - 1258  2016年  [査読有り]

    DOI PubMed

    Scopus

  • Passive Acoustic Monitoring the Diel, Lunar, Seasonal and Tidal Patterns in the Biosonar Activity of the Indo-Pacific Humpback Dolphins (Sousa chinensis) in the Pearl River Estuary, China

    Zhi-Tao Wang, Paul E. Nachtigall, Tomonari Akamatsu, Ke-Xiong Wang, Yu-Ping Wu, Jian-Chang Liu, Guo-Qin Duan, Han-Jiang Cao, Ding Wang

    PLOS ONE   10 ( 11 )  2015年11月  [査読有り]

    DOI PubMed

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    53
    被引用数
    (Scopus)
  • Seasonal Distribution of Indo-Pacific Humpback Dolphins at an Estuarine Habitat: Influences of Upstream Rainfall

    Tzu Hao Lin, Tomonari Akamatsu, Lien Siang Chou

    Estuaries and Coasts   38 ( 4 ) 1376 - 1384  2015年10月

    DOI

    Scopus

    33
    被引用数
    (Scopus)
  • Acoustic characteristics of biosonar sounds of free-ranging botos (Inia geoffrensis) and tucuxis (Sotalia fluviatilis) in the Negro River, Amazon, Brazil

    Yukiko Yamamoto, Tomonari Akamatsu, Vera M.F. Da Silva, Yayoi Yoshida, Shiro Kohshima

    Journal of the Acoustical Society of America   138 ( 2 ) 687 - 693  2015年08月

    DOI PubMed

    Scopus

    7
    被引用数
    (Scopus)
  • Target strength spectra of tracked individual fish in schools

    Masanori Ito, Ikuo Matsuo, Tomohito Imaizumi, Tomonari Akamatsu, Yong Wang, Yasushi Nishimori

    FISHERIES SCIENCE   81 ( 4 ) 621 - 633  2015年07月  [査読有り]

    DOI

    Scopus

    7
    被引用数
    (Scopus)
  • Issues and an optimal application of acoustic survey for freshwater cetaceans

    Arnab Das, Tomonari Akamatsu

    2015 IEEE Underwater Technology, UT 2015    2015年05月

     概要を見る

    Freshwater cetaceans are among the data deficient and now recognized as the most threatened group of marine mammals. Large scale studies are required to be done on an urgent basis to ensure reasonable chance of survival for these species. A detailed analysis of the freshwater habitats globally, indicate tropical shallow environment (important for the survival of the freshwater cetaceans). Visual surveys being employed for abundance estimates have significant limitations and acoustic surveys have recently been identified as effective alternative and could complement the visual surveys for conservation efforts. However, two major issues can be prominent such as shallow water sound propagation and noise pollutions. It is well known that shallow waters result in multiple interaction of the acoustic signal with the surface and the bottom prior to being received at the hydrophone receiver. The tropical waters further cause random surface and bottom behaviour resulting in substantial site specific underwater channel fluctuations being coupled to the desired marine mammal signal. Thus, the acoustic survey efforts in the tropical shallow habitats are highly sensitive to the local conditions and demand efforts to mitigate the underwater channel fluctuations while pursuing analysis efforts on the received signal. Increasing population in these regions has resulted in unregulated waterborne activities linked to economic growth. Such activities have caused significant increase in the ambient noise in these habitats. The effectiveness of acoustic sensors is further limited by the high ambient noise in the habitat and could also impact survival chances of these critically endangered species. This work attempts to put in perspective the challenges of acoustic surveys in tropical shallow habitats and provide a way ahead for effective passive acoustic monitoring of the freshwater cetaceans globally.

    DOI

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  • 水産生物の音響による行動制御と可視化技術の開発

    赤松 友成

    日本水産学会誌   81 ( 3 ) 389 - 392  2015年05月  [査読有り]

    DOI CiNii

    Scopus

    1
    被引用数
    (Scopus)
  • Yangtze finless porpoises along the main channel of Poyang Lake, China: Implications for conservation

    Dong Lijun, Wang Ding, Wang Kexiong, li Songhai, Mei Zhigang, Wang Shiyong, Akamatsu Tomonari, Kimura Satoko

    MARINE MAMMAL SCIENCE   31 ( 2 ) 612 - 628  2015年04月  [査読有り]

    DOI

    Scopus

    38
    被引用数
    (Scopus)
  • Passive acoustic monitoring of Japanese spiny lobster stridulating sounds

    Mumi Kikuchi, Tomonari Akamatsu, Tomohiro Takase

    FISHERIES SCIENCE   81 ( 2 ) 229 - 234  2015年03月  [査読有り]

    DOI

    Scopus

    8
    被引用数
    (Scopus)
  • Frequent and prolonged nocturnal occupation of port areas by Yangtze finless porpoises (Neophocaena asiaeorientalis): Forced choice for feeding?

    Zhitao Wang, Tomonari Akamatsu, Zhigang Mei, Lijun Dong, Tomohito Imaizumi, Kexiong Wang, Ding Wang

    INTEGRATIVE ZOOLOGY   10 ( 1 ) 122 - 132  2015年01月  [査読有り]

    DOI PubMed

    Scopus

    55
    被引用数
    (Scopus)
  • Feasibility study of underwater passive acoustic observations of killer whales using A-tag

    Masakazu Arima, Hirofumi Tonai, Tomonari Akamatsu, Hiroya Minakuchi

    World Automation Congress Proceedings     291 - 296  2014年10月

     概要を見る

    It is very important to recognise marine biodiversity and to maintain sound ocean ecosystems for long-term and continuous utilisation of the ecosystems services. To ensure this end, ocean environment and ecosystem should be monitored over the long term and a wide range of ocean areas. The purpose of this research is a feasibility study of underwater acoustic observations of marine mammals using a passive acoustic data logger, A-tag. Final goal of this research is to realise the long-term and wide-range monitoring of ocean ecosystems using autonomous underwater gliders, and to evaluate the soundness of ocean ecosystems and environments. This paper deals with underwater acoustic observations of killer whales (Orcinus orca) and analyses of their vocalisation. Underwater passive acoustic observations were conducted at the Prince William Sound, Alaska, USA in the summer of 2013. Direction of vocalisation source was analysed from the time arrival difference between two hydrophones of A-tag. It was demonstrated that the result of acoustic observations of killer whales' vocalisations agreed well with their actual behaviours by visual observations.

    DOI

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    1
    被引用数
    (Scopus)
  • Sound variation and function in captive Commerson's dolphins (Cephalorhynchus commersonii).

    Yayoi M Yoshida, Tadamichi Morisaka, Mai Sakai, Mari Iwasaki, Ikuo Wakabayashi, Atsushi Seko, Masahiko Kasamatsu, Tomonari Akamatsu, Shiro Kohshima

    Behavioural processes   108   11 - 9  2014年10月  [査読有り]  [国際誌]

     概要を見る

    Commerson's dolphin (Cephalorhynchus commersonii), one of the smallest dolphin species, has been reported to produce only narrow-band high-frequency (NBHF) clicks and no whistles. To clarify their sound repertoire and examine the function of each type, we analysed the sounds and behaviour of captive Commerson's dolphins in Toba Aquarium, Japan. All recorded sounds were NBHF clicks with peak frequency >110kHz. The recorded click-trains were categorised into four types based on the changing pattern of their Inter-click intervals (ICI): Decreasing type, with continuously decreasing ICI during the last part of the train; Increasing type, with continuously increasing ICI during the last part; Fluctuating type, with fluctuating ICI; and Burst-pulse type, with very short and constant ICI. The frequency of the Decreasing type increased when approaching an object newly introduced to the tank, suggesting that the sound is used for echolocation on approach. The Burst-pulse type suddenly increased in front of the object and was often oriented towards it, suggesting that it was used for echolocation in close proximity to the object. In contrast, the Increasing type was rarely recorded during approach, but increased when a dolphin approached another dolphin. The Increasing and Burst-pulse types also increased when dolphins began social behaviours. These results suggest that some NBHF clicks have functions other than echolocation, such as communication.

    DOI PubMed J-GLOBAL

    Scopus

    17
    被引用数
    (Scopus)
  • Long-term passive acoustic monitoring revealed seasonal and diel patterns of cetacean presence in the Istanbul Strait

    Ayhan Dede, Ayaka Amaha Öztürk, Tomonari Akamatsu, Arda M. Tonay, Bayram Öztürk

    Journal of the Marine Biological Association of the United Kingdom   94 ( 6 ) 1195 - 1202  2014年09月

     概要を見る

    The Istanbul Strait (Bosphorus) is a part of the Turkish Straits System, connecting the Aegean Sea and the Black Sea. There are three cetacean species in the Strait, namely the harbour porpoise (Phocoena phocoena), the common dolphin (Delphinus delphis), and the bottlenose dolphin (Tursiops truncatus). To monitor the presence of the cetaceans, a fixed stereo passive acoustic monitoring system (A-tag) was deployed in the middle of the Strait from July 2009 to September 2010. In total 26,814 click trains were detected. Presence, direction and inter-click intervals of phonating cetaceans were measured. Most click trains were detected during the night time. Diel presence pattern was prominent in March and April. In spring, the cetaceans were concentrated in one specific direction from the fixed monitoring system. In contrast, they were found in all directions for the rest of the year. Short range sonar (inter-click intervals (ICIs) less than 50 ms) was commonly detected in spring. During the rest of the year ICIs could reach up to 150 ms. All these findings suggest that they were feeding or socializing in spring and mostly travelling in the other seasons. It is well known that pelagic fish such as sprat and bluefish start their migration from the Aegean Sea to the Black Sea in spring. This study suggests that the cetaceans use the middle part of the Strait for feeding on the pelagic fish in spring when the fish migration has just started. © 2013 Marine Biological Association of the United Kingdom .

    DOI

    Scopus

    24
    被引用数
    (Scopus)
  • Detection of manatee feeding events by animal-borne underwater sound recorders

    Mumi Kikuchi, Tomonari Akamatsu, Daniel Gonzalez-Socoloske, Diogo A. De Souza, Leon D. Olivera-Gomez, Vera M.F. Da Silva

    Journal of the Marine Biological Association of the United Kingdom   94 ( 6 ) 1139 - 1146  2014年09月

     概要を見る

    Studies of the feeding behaviour of aquatic species in their natural environment are difficult, since direct observations are rarely possible. In this study, a newly developed animal-borne underwater sound recorder (AUSOMS-mini) was applied to captive Amazonian (Trichechus inunguis) and Antillean (Trichechus manatus manatus) manatees in order to directly record their feeding sounds. Different species of aquatic plants were offered to the manatees separately. Feeding sounds were automatically extracted using a custom program developed with MATLAB. Compared to ground truth data, the program correctly detected 65-79% of the feeding events, with a 7.3% or lower false alarm rate, which suggests that this methodology is a useful recorder of manatee feeding events. All manatees foraged during both the daytime and night-time. However, manatees tended to be less active and masticated slower during the night than during the day. The manatee mastication cycle duration depended on plant species and individual. This animal-borne acoustic monitoring system could greatly increase our knowledge of manatee feeding ecology by providing the exact time, duration and number of feeding events, and potentially the plant species being fed on. © 2013 Marine Biological Association of the United Kingdom .

    DOI

    Scopus

    8
    被引用数
    (Scopus)
  • Acoustically invisible feeding blue whales in Northern Icelandic waters

    Tomonari Akamatsu, Marianne Helene Rasmussen, Maria Iversen

    Journal of the Acoustical Society of America   136 ( 2 ) 939 - 944  2014年08月

    DOI PubMed

    Scopus

    9
    被引用数
    (Scopus)
  • Acoustic discrimination between harbor porpoises and delphinids by using a simple two-band comparison

    Saho Kameyama, Tomonari Akamatsu, Ayhan Dede, Ayaka Amaha Öztürk, Nobuaki Arai

    Journal of the Acoustical Society of America   136 ( 2 ) 922 - 929  2014年08月

    DOI PubMed

    Scopus

    6
    被引用数
    (Scopus)
  • Acoustic capture-recapture method for towed acoustic surveys of echolocating porpoises

    Satoko Kimura, Tomonari Akamatsu, Lijun Dong, Kexiong Wang, Ding Wang, Yasutoki Shibata, Nobuaki Arai

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   135 ( 6 ) 3364 - 3370  2014年06月  [査読有り]

    DOI PubMed

    Scopus

    6
    被引用数
    (Scopus)
  • To see or not to see: Investigating detectability of ganges river dolphins using a combined visual-acoustic survey

    Nadia I. Richman, James M. Gibbons, Samuel T. Turvey, Tomonari Akamatsu, Benazir Ahmed, Emile Mahabub, Brian D. Smith, Julia P.G. Jones

    PLoS ONE   9 ( 5 )  2014年05月

    DOI PubMed

    Scopus

    30
    被引用数
    (Scopus)
  • An Evaluation of the Performance of a hydrophone on sea floor

    Shuhei Nishida, Katsuyoshi Kawaguchi, Tomohito Imaizumi, Tomonari Akamatsu

    OCEANS 2014 - TAIPEI    2014年  [査読有り]

     概要を見る

    DONET (Dense Ocean-floor Network system for Earthquakes and Tsunamis) is a submarine cabled real-time observation network for earthquakes and tsunamis monitoring around the Nankai trough, southwestern Japan. The scheduled twenty observatories have operated since August 2011. Various sensors such as a broadband seismometer, a pressure gauge, a hydrophone, etc. are equipped with each observatory, because DONET has expected to obtain the data to understand the Nankai trough mega thrust earthquake seismogenic zones. Therefore, in order to supply data stably, it's important to have a method of an investigation of the performance of each sensor in DONET.
    In this research, we will evaluate the performance of a hydrophone of DONET. The reference hydrophone was installed several meters from an observatory of DONET. Here, it assumes that both hydrophones will record the acoustic data according to same sound source. And, we will evaluate the performance of a hydrophone by the comparison between reference hydrophone and DONET's one in actual field, and will report the result of the evaluations.

    DOI

    Scopus

  • Distribution patterns of Yangtze finless porpoises in the Yangtze River: Implications for reserve management

    X. Zhao, D. Wang, S. T. Turvey, B. Taylor, T. Akamatsu

    Animal Conservation   16 ( 5 ) 509 - 518  2013年10月

    DOI

    Scopus

    50
    被引用数
    (Scopus)
  • Diel changes in the movement patterns of Ganges River dolphins monitored using stationed stereo acoustic data loggers

    Yukiko Sasaki-Yamamoto, Tomonari Akamatsu, Tamaki Ura, Harumi Sugimatsu, Junichi Kojima, Rajendar Bahl, Sandeep Behera, Shiro Kohshima

    MARINE MAMMAL SCIENCE   29 ( 4 ) 589 - 605  2013年10月  [査読有り]

    DOI

    Scopus

    19
    被引用数
    (Scopus)
  • An automatic detection algorithm for extracting the representative frequency of cetacean tonal sounds

    Tzu-Hao Lin, Lien-Siang Chou, Tomonari Akamatsu, Hsiang-Chih Chan, Chi-Fang Chen

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   134 ( 3 ) 2477 - 2485  2013年09月  [査読有り]

    DOI PubMed

    Scopus

    26
    被引用数
    (Scopus)
  • A multimodal detection model of dolphins to estimate abundance validated by field experiments

    Akamatsu Tomonari, Ura Tamaki, Sugimatsu Harumi, Bahl Rajendar, Behera Sandeep, Panda Sudarsan, Khan Muntaz, Kar S. K, Kar C. S, Kimura Satoko, Sasaki-Yamamoto Yukiko

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   134 ( 3 ) 2418 - 2426  2013年09月  [査読有り]

    DOI PubMed

    Scopus

    11
    被引用数
    (Scopus)
  • Tidal influences on the habitat use of Indo-Pacific humpback dolphins in an estuary

    Tzu Hao Lin, Tomonari Akamatsu, Lien Siang Chou

    Marine Biology   160 ( 6 ) 1353 - 1363  2013年06月

    DOI

    Scopus

    43
    被引用数
    (Scopus)
  • Variation in the production rate of biosonar signals in freshwater porpoises

    Kimura Satoko, Akamatsu Tomonari, Wang Ding, Li Songhai, Wang Kexiong, Yoda Ken

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   133 ( 5 ) 3128 - 3134  2013年05月  [査読有り]

    DOI PubMed

    Scopus

    14
    被引用数
    (Scopus)
  • Biosonar, diving and movements of two tagged white-beaked dolphin in Icelandic waters

    M. H. Rasmussen, T. Akamatsu, J. Teilmann, G. Vikiugsson, L. A. Miller

    DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY   88-89   97 - 105  2013年04月  [査読有り]

    DOI

    Scopus

    28
    被引用数
    (Scopus)
  • Biosonar, dive, and foraging activity of satellite tracked harbor porpoises (Phocoena phocoena)

    Meike Linnenschmidt, Jonas Teilmann, Tomonari Akamatsu, Rune Dietz, Lee A. Miller

    MARINE MAMMAL SCIENCE   29 ( 2 ) E77 - E97  2013年04月  [査読有り]

    DOI

    Scopus

    72
    被引用数
    (Scopus)
  • Observation of in situ tuna behavior around the fisheries aggregating devises (FADs) by using passive and active acoustic methods

    T. Imaizumi, T. Akamatsu, T. Oshima, K. Yokota, H. Iga, I. Fusejima, Y. Wang, M. Ito, I. Matsuo, Y. Takao, S. Hasegawa

    2013 IEEE International Underwater Technology Symposium, UT 2013    2013年

     概要を見る

    The by-catch of bigeye tuna (Thunnus obesus) has been serious problem for commercial fisheries of skip jack tuna (Katsuwonus pelamis) due to the strong constrain of quarter for each species. Selective catch of skip jack tuna with avoiding by-catch of bigeye tuna is required for sustainable and effective fisheries. Light stimuli were applied in attempts to remove unnecessary tuna species and let them escape through the mesh or underneath of a round net. The movements of fish were observed with coded pingers (passive method) and a broadband quantitative split-beam echo sounder (active method). Newly introduced micro coded pinger (Fusion Inc., Tokyo) for this observation resulted in longer survival or / and retention of tagged fish comparing with previous survey periods. Three hydrophone array systems were deployed on each survey ships (Shoyo-maru, Nippon-maru, and Nippon-maru's boat). The pinger transmitted 31 bits M-sequence signal every 1 second. Movements of multiple tagged fish were able to be observed at the same time. Not only depth change of each fish, but also three dimensional locations could be calculated. In the mean time, schools of fish were observed by the broadband echo sounder near the FADs. The 3D tracks of fishes which were estimated by active way with high distance resolution showed the fish swam deeper at sun rising that was consistent with passive monitoring result. Consequently large data sets of the movement of in situ bigeye tuna and skipjack tuna around FADs were obtained. © 2013 IEEE.

    DOI

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  • Counting animals using vocalizations; A case study in dolphins

    T. Akamatsu, T. Ura, H. Sugimatsu, R. Bahl, S. Behera, S. Panda, M. Khan, S. K. Kar, C. S. Kar, S. Kimura, Y. Sasaki-Yamamoto

    2013 IEEE International Underwater Technology Symposium, UT 2013    2013年

     概要を見る

    Abundance estimation of marine mammals requires matching of detection of an animal or a group of animals by two independent means. A multimodal detection model using visual and acoustic cues (surfacing and phonation) that enables abundance estimation of dolphins is proposed. The method does not require a specific time window to match the cues of both means for applying mark-recapture method. The proposed model was evaluated using data obtained in field observations of Ganges River dolphins and Irrawaddy dolphins, as examples of dispersed and condensed distributions of animals, respectively. The acoustic detection probability was approximately 80 %, 20 % higher than that of visual detection for both species, regardless of the distribution of the animals in the present study sites. The abundance estimates of Ganges River dolphins and Irrawaddy dolphins fairly agreed with the numbers reported in previous monitoring studies. The single animal detection probability was smaller than that of larger cluster size, as predicted by the model and confirmed by field data. However, dense groups of Irrawaddy dolphins showed difference in cluster sizes observed by visual and acoustic methods. Lower detection probability of single clusters of this species seemed to be caused by the clumped distribution of this species. © 2013 IEEE.

    DOI

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    3
    被引用数
    (Scopus)
  • An evaluation about the performance of a hydrophone on seafloor

    S. Nishida, K. Kawaguchi, T. Imaizumi, T. Akamatsu

    2013 IEEE International Underwater Technology Symposium, UT 2013    2013年

     概要を見る

    DONET (Dense Ocean-floor Network system for Earthquakes and Tsunamis) is a submarine cabled real-time observation network for earthquakes and tsunamis monitoring around the Nankai trough, southwestern Japan. The scheduled twenty observatories have operated since August 2011. Various sensors such as a broadband seismometer, a pressure gauge, a hydrophone, etc. are equipped with each observatory, because DONET has expected to obtain the data to understand the Nankai trough mega thrust earthquake seismogenic zones. Therefore, in order to supply data stably, it's important to have a method of an investigation of the performance of each sensor in DONET. In this research, we will evaluate the performance of a hydrophone of DONET. The reference hydrophone was installed several meters from an observatory of DONET. Here, it assumes that both hydrophones will record the acoustic data according to same sound source. And, we will evaluate the performance of a hydrophone by the comparison between reference hydrophone and DONET's one in actual field, and will report the result of the evaluations. © 2013 IEEE.

    DOI

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  • Classification of fish schools based on acoustic features associated with tilt angle

    M. Ito, I. Matsuo, T. Imaizumi, T. Akamatsu, Y. Wang, Y. Nishimori

    2013 IEEE International Underwater Technology Symposium, UT 2013    2013年

     概要を見る

    It is required to monitor fish species and amount in order to save marine resources. In the current study, broadband split-beam echo sounder was used to survey fish resources. The echo sounder was useful to track individual fish in schools because individual fish echoes in the schools could be separately measured and three dimensional positions of the echoes could be accurately estimated. It is well known that the acoustic features of fish echoes are closely related to the body length and the apparent tilt angle of a fish. The tilt angle could be estimated by individual tracking. Echoes from fish schools were measured for several hours in the ocean. Echo signals were gathered into one block within a certain depth and a period of time and analyzed to track individual fish in the schools. Target strength was calculated from the individual fish echo and associated with the tilt angle, which was estimated by the individual tracking result. The feature in each block was statistically calculated by averaging target strengths based on the tilt angles. The blocks of the signals were classified by K-means method with the features and divided into some clusters. As a result of the clustering, fish schools in the blocks could be classified. The distribution of the clusters was dependent on both time and depth. © 2013 IEEE.

    DOI

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    1
    被引用数
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  • Algorithm for automatic acoustic detection of ship and marine mammals

    Akiko Sakurada, Tomonari Akamatsu, Naoya Umeda

    IFAC Proceedings Volumes (IFAC-PapersOnline)   9 ( PART 1 ) 352 - 355  2013年

     概要を見る

    Responding to the increasing number, size, and speed of commercial ships, the underwater noise is also increasing which could result in a possible adverse impact on marine lives. For clarifying this possible concern, a method for measurement of ship noise and marine lives is required, especially for marine mammals which are sensitive for the frequency range of ship noise. In order to enable to observe marine mammal's behavior and the ship noise simultaneously, this study developed an algorithm to detect ship noise, added to a conventional dolphin detection algorithm. The ship noise is obtained by eliminating some nature sounds and the dolphin's sonar sound. Both dolphin's sounds and ship noises can be separated efficiently so that the noise can be identified using sample data. Further improvement of monitoring system and algorithm are future tasks. © IFAC.

    DOI

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  • Clustering of acoustic fish features tracked by broadband split-beam echo sounder

    Masanori Ito, Ikuo Matsuo, Tomohito Imaizumi, Tomonari Akamatsu, Yong Wang, Yasushi Nishimori

    Proceedings of Meetings on Acoustics   19  2013年  [査読有り]

     概要を見る

    Monitoring fish species and amount with acoustical instruments is a challenging problem to survey fish resources in the ocean. Broadband split-beam echo sounder was useful to observe individual fish behavior in schools. Echoes from fish schools were measured from an anchored vessel for several hours. Echo signals were gathered into one block within a certain depth and a period of time and analyzed to track individual fish in the schools. Target strength was calculated from the individual fish echo and associated with tilt angle which could be estimated by using the tracking result. Feature in each block was statistically calculated by averaging target strengths according to the tilt angles. The blocks of the signals were clustered by K-means method with the features and divided into some clusters. The distribution of the clusters in time and depth was investigated. It appeared that the distributions of the clusters were dependent on both time and depth. Clustering of the features would be effective to monitor diversity of fish in the ocean. © 2013 Acoustical Society of America.

    DOI

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  • First human-caused extinction of a cetacean species?

    Samuel T. Turvey, Robert L. Pitman, Barbara L. Taylor, Jay Barlow, Tomonari Akamatsu, Leigh A. Barrett, Xiujiang Zhao, Randall R. Reeves, Brent S. Stewart, Kexiong Wang, Zhuo Wei, Xianfeng Zhang, L. T. Pusser, Michael Richlen, John R. Brandon, Ding Wang

    Biology Letters   3 ( 5 ) 537 - 540  2012年10月  [査読有り]

    DOI PubMed

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    436
    被引用数
    (Scopus)
  • Acoustic tagging for counting feeding events of captive Amazonian manatees

    Mumi Kikuchi, Fernando C. W. Rosas, Diogo Alexandre de Souza, Tomonari Akamatsu, Vera M. F. da Silva

    The Journal of the Acoustical Society of America   131   3523 - 3523  2012年04月

     概要を見る

    <jats:p>The Amazonian manatee is one of four extant species in the mammalian order Sirenia. They are restricted to the freshwater rivers, lakes and floodplains of the Amazonian river basin where they eat floating and emergent aquatic plants. Visual observation of wild manatees is nearly impossible because of the turbid water and tiny exposure of nose at gentle respiration movement, which consequently precludes study of their underwater behaviour. In this study, we applied animal-worn sound recorder (AUSOMS-mini, System Intec Co., Tokyo, Japan) to two captive Amazonian manatees at INPA, Brazil, in order to record their mastication sounds. Five species of aquatic plants were offered to the manatees separately. Mastication-sounds were extracted by custom made software developed on Matlab for off-line analysis. The mastication intervals and temporal sound structure depended on species of plants. In addition, individual difference of mastication intervals observed in the two manatees was probably due to different body sizes. Overnight recording showed that both manatees kept feeding for more than 0.5 hours followed by 1.6 ± 1.3 hours interruption of feeding. Other sounds such as insect calls, rainfall, and vocalizations of other manatees could be useful to understand habitat selection, weather and presence of conspecifics. Acknowledgment Research and Development Program for New Bio-industry Initiatives</jats:p>

    DOI

  • Seasonal changes in the local distribution of Yangtze finless porpoises related to fish presence

    Kimura Satoko, Akamatsu Tomonari, Li Songhai, Dong Lijun, Wang Kexiong, Wang Ding, Arai Nobuaki

    MARINE MAMMAL SCIENCE   28 ( 2 ) 308 - 324  2012年04月  [査読有り]

    DOI

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    86
    被引用数
    (Scopus)
  • Clumped distribution of vocalising dugongs (Dugong dugon) monitored by passive acoustic and visual observations in Thai waters

    Kotaro Ichikawa, Tomonari Akamatsu, Tomio Shinke, Nobuaki Arai, Kanjana Adulyanukosol

    Australian Acoustical Society Conference 2012, Acoustics 2012: Acoustics, Development, and the Environment     529 - 532  2012年

     概要を見る

    Distribution pattern of dugongs is a key component for space-based managements. Vocal interaction of dugongs may result in a distinctive distribution pattern. This study described the distribution patterns of vocalising dugongs, solitary and cow-calf pairs of dugongs. Total of 31 hours and 24 minutes of aerial surveys over southern Thai waters were conducted to observe distribution of the dugongs in 2006, 2008 and 2010. We also conducted towed acoustic surveys to observe the distribution of vocalising dugongs. Total of 473 adult dugongs and 122 calves and 223 vocalizations were found. The distribution of vocalising dugongs was clumped with the range of about 1 km 2. Groups with cow-calf pairs (9 animals on average) were also clumped. Their distribution range was about 3 km2 and did not overlap that of vocalising dugongs. Average number of individuals in groups without cow-calf pairs was about 1, indicating that the most of the group members were solitary. They distributed widely throughout the focal area with the distribution range of about 41 km2.

  • Cepstral analysis for discrimination of fish species by using the dolphin-like sonar sounds

    I. Matsuo, M. Ito, T. Imaizumi, T. Akamatsu, Y. Wang, Y. Nishimori

    11th European Conference on Underwater Acoustics 2012, ECUA 2012   34 1 ( PART 3 ) 496 - 500  2012年

     概要を見る

    The broadband target strength (TS) pattern could be estimated from echoes of the tethered fish by using the broadband signal. This TS pattern was computed by Fourier transform from outputs of cross-correlation function between the emitted signal and echoes from each fish at each tilt angle. Since echoes from fish included multiple reflections, the TS spectra included the interferences among them, as shown in Fig. 4. The degrees of these interferences could be computed by the average of enveloped cepstral patterns at the time, which is larger than 25 microseconds, corresponding to 18 mm along the range axis. As shown in Fig. 5 (b), these degrees were different with four species at the negative tilt angles while these were almost same with them at the positive tilt angles. As shown in Fig.5 (a), it was clarified that averaged TS was changed dependent on fish species and tilt angles.

  • Zigzag transect survey by towed passive acoustic method for finless porpoise in the Yangtze River.

    Proceedings of the 7th International Symposium on SEASTAR2000 and Asian Bio-logging Science.     37 - 41  2012年  [査読有り]

    CiNii

  • Do Porpoises Choose Their Associates? A New Method for Analyzing Social Relationships among Cetaceans

    Mai Sakai, Ding Wang, Kexiong Wang, Songhai Li, Tomonari Akamatsu

    PLOS ONE   6 ( 12 ) e28836  2011年12月  [査読有り]

    DOI PubMed

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    14
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  • Passive acoustic survey of Yangtze finless porpoises using a cargo ship as a moving platform

    Lijun Dong, Ding Wang, Kexiong Wang, Songhai Li, Shouyue Dong, Xiujiang Zhao, Tomonari Akamatsu, Satoko Kimura

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   130 ( 4 ) 2285 - 2292  2011年10月  [査読有り]

    DOI PubMed

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    14
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  • An international quiet ocean experiment

    Ian L. Boyd, George Frisk, Ed Urban, Peter Tyack, Jesse Ausubel, Sophie Seeyave, Doug Cato, Brandon Southal, Michael Weise, Rex Andrew, Tomonari Akamatsu, René Deke Ling, Christine Erbe, David Farmer, Roger Gentry, Tom Gross, Anthony Hawkins, Fenghua Li, Kathy Metcalf, James H. Miller, David Moretti, Cristian Rodrigo, Tomio Shinke

    Oceanography   24 ( 2 ) 174 - 181  2011年06月

    DOI

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    73
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  • Callback response of dugongs to conspecific chirp playbacks

    Kotaro Ichikawa, Tomonari Akamatsu, Tomio Shinke, Kanjana Adulyanukosol, Nobuaki Arai

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   129 ( 6 ) 3623 - 3629  2011年06月  [査読有り]

    DOI PubMed

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    24
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  • Echolocation signals of Heaviside's dolphins (Cephalorhynchus heavisidii)

    Tadamichi Morisaka, Leszek Karczmarski, Tomonari Akamatsu, Mai Sakai, Steve Dawson, Meredith Thornton

    Journal of the Acoustical Society of America   129 ( 1 ) 449 - 457  2011年01月  [査読有り]  [国際誌]

    DOI PubMed

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    35
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  • Preliminary evaluation of underwater sound detection by the cephalopod statocyst using a forced oscillation model

    Kenzo Kaifu, Tomonari Akamatsu, Susumu Segawa

    Acoustical Science and Technology   32 ( 6 ) 255 - 260  2011年  [査読有り]

    DOI

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    8
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  • A stereo acoustic event recorder for monitoring abundance and movements of dolphins and porpoises

    Tomonari Akamatsu, Satoko Kimura, Songhai Li, Lijun Dong, Kexiong Wang, Ding Wang

    2011 IEEE Symposium on Underwater Technology, UT'11 and Workshop on Scientific Use of Submarine Cables and Related Technologies, SSC'11    2011年  [査読有り]

     概要を見る

    A multi-platform ultrasonic event recorder for towing and stationed monitoring of cetaceans was developed. A stereo acoustic event recorder (A-tag) was originally developed to observe biosonar behavior by tagging on dolphins and porpoises in the wild. In recent years, A-tag has been applied for the acoustic transect to count the number of dolphins and porpoises, and for the long term stationed observation. © 2011 IEEE.

    DOI

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    3
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  • Density estimation of Yangtze finless porpoises using passive acoustic sensors and automated click train detection

    Kimura Satoko, Akamatsu Tomonari, Li Songhai, Dong Shouyue, Dong Lijun, Wang Kexiong, Wang Ding, Arai Nobuaki

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   128 ( 3 ) 1435 - 1445  2010年09月  [査読有り]

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    38
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  • Widespread passive acoustic detection of Yangtze finless porpoise using miniature stereo acoustic data-loggers: A review

    Li Songhai, Akamatsu Tomonari, Dong Lijun, Wang Kexiong, Wang Ding, Kimura Satoko

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   128 ( 3 ) 1476 - 1482  2010年09月  [査読有り]

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    22
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  • Seasonal and diurnal presence of finless porpoises at the corridor to the ocean from a semi‐closed bay habitat.

    Tomonari Akamatsu, Kiyomi Nakamura, Ryo Kawabe, Seishiro Furukawa, Hiromi Murata, Akihiro Kawakubo, Masayuki Komaba

    The Journal of the Acoustical Society of America   127 ( 3 ) 1825 - 1825  2010年03月

    DOI

  • Seasonal and diurnal presence of finless porpoises at a corridor to the ocean from their habitat

    Tomonari Akamatsu, Kiyomi Nakamura, Ryo Kawabe, Seishiro Furukawa, Hiromi Murata, Akihiro Kawakubo, Masayuki Komaba

    Marine Biology   157 ( 8 ) 1879 - 1887  2010年

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  • Detection of yangtze finless porpoises in the poyang lake mouth area via passive acoustic data-loggers

    Songhai Li, Shouyue Dong, Satoko Kimura, Tomonari Akamatsu, Kexiong Wang, Ding Wang

    Biology, Evolution and Conservation of River Dolphins within South America and Asia     341 - 356  2010年

  • Scanning sonar of rolling porpoises during prey capture dives

    T. Akamatsu, D. Wang, K. Wang, S. Li, S. Dong

    JOURNAL OF EXPERIMENTAL BIOLOGY   213 ( 1 ) 146 - 152  2010年01月  [査読有り]

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    48
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  • A trial of tracking of echolocating finless porpoise by two stationary passive acoustic monitoring systems.

    Proceedings of the 5th International Symposium on SEASTAR2000 and Asian Bio-logging Science.     73 - 76  2010年  [査読有り]

    CiNii

  • Detection probability of vocalizing dugongs during playback of conspecific calls

    Kotaro Ichikawa, Tomonari Akamatsu, Tomio Shinke, Kotoe Sasamori, Yukio Miyauchi, Yuki Abe, Kanjana Adulyanukosol, Nobuaki Arai

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   126 ( 4 ) 1954 - 1959  2009年10月  [査読有り]

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    18
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  • Analysis of the temporal structure of fish echoes using the dolphin broadband sonar signal

    Ikuo Matsuo, Tomohito Imaizumi, Tomonari Akamatsu, Masahiko Furusawa, Yasushi Nishimori

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   126 ( 1 ) 444 - 450  2009年07月  [査読有り]

    DOI PubMed

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    5
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  • Localization and tracking of phonating finless porpoises using towed stereo acoustic data-loggers

    Songhai Li, Tomonari Akamatsu, Ding Wang, Kexiong Wang

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   126 ( 1 ) 468 - 475  2009年07月  [査読有り]

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    24
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  • 自動イカ釣機の釣具ライン巻き上げ速度がアカイカの擬餌針捕捉行動に及ぼす影響(短報)

    黒坂 浩平, 山下 秀幸, 越智 洋介, 小河 道生, 赤松 友成, 稲田 博史, 渡部 俊広, KOHEI KUROSAKA, HIDEYUKI YAMASHITA, YOUSUKE OCHI, MICHIO OGAWA, TOMONARI AKAMATSU, HIROSHI INADA, TOSHIHIRO WATANABE, Marine Fisheries Research and Development Center Fisheries Research Agency, Marine Fisheries Research and Development Center Fisheries Research Agency, Marine Fisheries Research and Development Center Fisheries Research Agency, Marine Fisheries Research and Development Center Fisheries Research Agency, National Research Institute of Fisheries Engineering Fisheries Research Agency, Department of Marine Bioscience Faculty of Marine Science Tokyo University of Marine Science and Technology

    日本水産学会誌 = Bulletin of the Japanese Society of Scientific Fisheries   75 ( 1 ) 83 - 85  2009年01月

     概要を見る

    アカイカの釣り落とし,すなわち擬餌針からの脱落を低減するために,巻き上げ過程における擬餌針の動きとアカイカの針掛かり状態との関係を調べた。自動イカ釣機の釣具ラインのワイヤーとナイロン道糸との連結部に加速度ロガーを取り付けて擬餌針の運動を計測した。その結果,アカイカ5個体が擬餌針に掛かる直前の平均巻き上げ速度は2.7m/s,2.5m/s,1.6m/s,1.5m/s,1.4m/sであった。この速度が1.5m/s前後では触腕以外の腕で擬餌針を捕捉し,2.5m/s程度の巻き上げ速度では触腕だけで捕捉する傾向が認められた。

    DOI CiNii

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    2
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  • Influence of autojigger's winding velocity on lure holding behavior of neon flying squid Ommastrephes bartrami,Influence of autojigger's winding velocity on lure holding behavior of neon flying squid Ommastrephes bartrami

    Kurosaka, K., Yamashita, H., Ochi, Y., Ogawa, M., Akamatsu, T., Inada, H., Watanabe, T.

    Nippon Suisan Gakkaishi (Japanese Edition)   75 ( 1 )  2009年

    DOI

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    2
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  • Measuring the target strength spectra of fish using dolphin-like short broadband sonar signals

    Imaizumi, T., Furusawa, M., Akamatsu, T., Nishimori, Y.

    Journal of the Acoustical Society of America   124 ( 6 )  2009年

    DOI PubMed

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    19
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  • Biosonar and auditory system of the Yangtze finless porpoise

    Songhai Li, Ding Wang, Kexiong Wang, Tomonari Akamatsu, Alexander Ya Supin, Vladimir V. Popov

    Endangered Species: New Research     1 - 13  2009年

  • Bilateral bioacoustics research of Chinese freshwater dolphins

    Tomonari Akamatsu, Ding Wang, Kexiong Wang

    Acoustical Science and Technology   30 ( 1 ) 13 - 17  2009年  [査読有り]

     概要を見る

    China has various ecologically important sites that provide wonderful research opportunities. The biosonar behavior of Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) in the semi-natural reserve, Hubei, China has been extensively studied for the past five years by the Japan Fisheries Research Agency and Institute of Hydrobiology, Chinese Academy of Sciences. Careful scanning and acoustical autofocusing behavior in porpoises was firstly observed in free-ranging conditions. The biosonar model obtained in this study allowed us to recently develop a broadband high-resolution sonar system called the Dolphin Sonar Simulator. Frequent biosonar production by finless porpoises also allowed an effective passive acoustical survey to be conducted of the animal along the entire habitat of this species in 2006. Bilateral collaboration with cutting-edge acoustical technologies was proven to be highly productive for basic behavioral science, engineering applications, and the conservation of endangered species. © 2009 The Acoustical Society of Japan.

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  • Small-scale towing survey combined acoustical and visual observation for finless porpoise in the Yangtze River.

    Proceedings of the 4th International Symposium on SEASTAR2000 and Asian Bio-logging Science.     63 - 65  2009年  [査読有り]

    CiNii

  • Comparison of stationary acoustic monitoring and visual observation of finless porpoises

    Kimura Satoko, Akamatsu Tomonari, Wang Kexiong, Wang Ding, Li Songhai, Dong Shouyue, Arai Nobuaki

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   125 ( 1 ) 547 - 553  2009年01月  [査読有り]

    DOI PubMed CiNii

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    60
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  • Abundance and conservation status of the Yangtze finless porpoise in the Yangtze River, China

    Zhao X, Barlow J, Taylor BL, Pitman RL, Wang K, Wei Z, Stewart BS, Turvey ST, Akamatsu T, Reeves RR, Wang D

    Biological conservation.    2008年12月

    DOI

  • Evidence of nighttime movement of finless porpoises through Kanmon Strait monitored using a stationary acoustic recording device

    Tomonari Akamatsu, Izumi Nakazawa, Takashi Tsuchiyama, Naoko Kimura

    FISHERIES SCIENCE   74 ( 5 ) 970 - 975  2008年10月

    DOI CiNii

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    17
    被引用数
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  • Underwater sound detection by cephalopod statocyst

    Kenzo Kaifu, Tomonari Akamatsu, Susumu Segawa

    FISHERIES SCIENCE   74 ( 4 ) 781 - 786  2008年08月

    DOI CiNii

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    49
    被引用数
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  • Simultaneous production of low- and high-frequency sounds by neonatal finless porpoises

    Songhai Li, Kexiong Wang, Ding Wang, Shouyue Dong, Tomonari Akamatsu

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   124 ( 2 ) 716 - 718  2008年08月

    DOI PubMed CiNii

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    17
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  • Estimation of the detection probability for Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) with a passive acoustic method

    T. Akamatsu, D. Wang, K. Wang, S. Li, S. Dong, X. Zhao, J. Barlow, B. S. Stewart, M. Richlen

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   123 ( 6 ) 4403 - 4411  2008年06月

    DOI PubMed CiNii

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    58
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  • Shipboard measurements of the hearing of the white-beaked dolphin Lagenorhynchus albirostris

    P. E. Nachtigall, T. A. Mooney, K. A. Taylor, L. A. Miller, M. H. Rasmussen, T. Akamatsu, J. Teilmann, M. Linnenschmidt, G. A. Vikingsson

    JOURNAL OF EXPERIMENTAL BIOLOGY   211 ( 4 ) 642 - 647  2008年02月

    DOI

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    45
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  • Indirect evidence of boat avoidance behavior of yangtze finless porpoises

    Songhai Li, Tomonari Akamatsu, Ding Wang, Kexiong Wang, Shouyue Dong, Xiujiang Zhao, Zhuo Wei, Xianfeng Zhang, Barbara Taylor, Leigh A. Barrett, Samuel T. Turvey, Randall R. Reeves, Brent S. Stewart, Michael Richlen, John R. Brandon

    Bioacoustics   17 ( 1-3 ) 174 - 176  2008年

    DOI

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    15
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  • The ontogeny of echolocation in a Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis)

    Songhai Li, Ding Wang, Kexiong Wang, Jianqiang Xiaob, Tomonari Akamatsu

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   122 ( 2 ) 715 - 718  2007年08月

    DOI PubMed CiNii

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    26
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  • Echolocation click sounds from wild inshore finless porpoise (Neophocaena phocaenoides sunameri) with comparisons to the sonar of riverine N. p. asiaeorientalis

    Songhai Li, Ding Wang, Kexiong Wang, Tornonari Akamatsu, Zhiqiang Ma, Jiabo Han

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   121 ( 6 ) 3938 - 3946  2007年06月

    DOI PubMed CiNii

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    37
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  • Stroke frequency, but not swimming speed, is related to body size in free-ranging seabirds, pinnipeds and cetaceans.

    Katsufumi Sato, Yutaka Watanuki, Akinori Takahashi, Patrick J O Miller, Hideji Tanaka, Ryo Kawabe, Paul J Ponganis, Yves Handrich, Tomonari Akamatsu, Yuuki Watanabe, Yoko o Mitani, Daniel P Costa, Charles-André Bost, Kagari Aoki, Masao Amano, Phil Trathan, Ari Shapiro, Yasuhiko Naito

    Proceedings. Biological sciences   274 ( 1609 ) 471 - 7  2007年02月  [国際誌]

    DOI PubMed

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    156
    被引用数
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  • Quantitative surveys of fish assemblage at a high-rise artificial fish reef by stationary underwater cameras

    Hideyuki Takahashi, Akihiko Matsuda, Tomonari Akamatsu, Norimasa Takagi

    International Symposium on Underwater Technology, UT 2007 - International Workshop on Scientific Use of Submarine Cables and Related Technologies 2007     463 - 466  2007年

     概要を見る

    Stationary underwater cameras were deployed to evaluate spatial and temporal distribution of fish assemblage inhabiting a high-rise artificial reef. The camera named FISCHOM has a stereo camera or a monaural camera on board and it can operate periodically by an arbitrary interval. We can acquire the information about fish fauna and fish size distribution and their time series of reef fish assemblages by the assessment using the FISCHOMs. Two surveys were conducted in the early summer and fall of 2005 at a high-rise artificial fish reef in the Sea of Japan. In both surveys, five FISCHOMs were fixed dispersedly on the reef and operated in an hour interval As a result, we could evaluate the spatial and temporal distribution of the fish assemblage and their seasonal variations around the reef about 20 days. In total, 48 thousands of fish were counted in both surveys. Pearl-spot chromis Chromis notata notata, jack mackerel Trachwusjaponkus, and rockfish Sebastes spp. were mainly observed. We confirmed these major species had stable diurnal cycles; they were observed in daytime and rarely observed in midnight The differences of the spatial distributions of the major species were found by comparing the results of each FISCHOMs. The folk lengths of the major species were estimated by stereo measurements. © 2007 IEEE.

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  • Comparison of echolocation behaviour between coastal and riverine porpoises

    Tomonari Akamatsu, Jonas Teilmann, Lee A. Miller, Jacob Tougaard, Rune Dietz, Ding Wang, Kexiong Wang, Ursula Siebert, Yasuhiko Naito

    2007 SYMPOSIUM ON UNDERWATER TECHNOLOGY AND WORKSHOP ON SCIENTIFIC USE OF SUBMARINE CABLES AND RELATED TECHNOLOGIES, VOLS 1 AND 2     563 - +  2007年  [査読有り]

     概要を見る

    Echolocation behaviour of a harbor porpoise and six finless porpoises was recorded in open-water systems using acoustic data loggers (A-tag). In total 1359 click trains were recorded during 4.6 h for the harbor porpoise and 46,240 click trains were recorded during 82.3 h for the finless porpoises. The harbor and finless porpoises produced sonar click trains every 12.3 and 6.4 s on average, respectively. During the inter-click-train interval, the porpoises were silent or produced clicks below 148 dB re. 1 mPa, the detection threshold of the tag. Ninety percent of the inter-click-train intervals were 20 s or less in both species. This means that porpoises frequently produce intense click trains. Click-train intervals lasting over 50 s constituted 1% of the total intervals in finless porpoises and 4% in the harbor porpoise. Both species swam without intense clicks for less than 10m in most cases, but occasionally remained silent or used undetected low-intensity clicks for more than 1 min. During these periods, the porpoises would be susceptible to entanglement in fishing nets.

    DOI

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    5
    被引用数
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  • Measurements of target strength spectra of metal spheres and live fish by using broad band sonar signals of dolphin

    Tomohito Imaizumi, Masahiko Furusawa, Tomonari Akamatsu, Yasushi Nishimori

    2007 SYMPOSIUM ON UNDERWATER TECHNOLOGY AND WORKSHOP ON SCIENTIFIC USE OF SUBMARINE CABLES AND RELATED TECHNOLOGIES, VOLS 1 AND 2     589 - +  2007年  [査読有り]

     概要を見る

    This paper describes a method and results of measurements of the target strength (TS) spectra of metal spheres and live fish using sonar signals of dolphins with a broadband system. First, we measured the broadband form function of a tungsten carbide and a copper sphere in a water tank and confirmed good agreements with the theoretical values. Second, we measured the TS spectra of three species of anaesthetized fish in a water tank. Although the spectra showed nearly similar tendencies of past measurements, they varied considerably among the species, the individuals, and the tilt angles. Third, we measured the TS spectra of tethered live fish suspended from a ship at the sea. In this case we removed the directivity of transducers by the tungsten carbide sphere suspended near the fish. The sonar signals of dolphin are effective to measure TS spectra of fish.

    DOI

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  • Analysis of the echo for identifying the temporal structure of the fish by using the broadband sonar signal of dolphin

    I. Matsuo, Tomohito Imaimmi, Masahiko Furusawa, Tomonari Akamatsu, Yasushi Nishimori, Shinji Ogawa

    2007 SYMPOSIUM ON UNDERWATER TECHNOLOGY AND WORKSHOP ON SCIENTIFIC USE OF SUBMARINE CABLES AND RELATED TECHNOLOGIES, VOLS 1 AND 2     583 - +  2007年  [査読有り]

     概要を見る

    Dolphins can recognize prey by using the broadband sonar signals. The echo from the fish contains components resulting from multiple reflections, for example, the swimbladder and body surface of the fish. It is necessary for identification of fish species to estimate the positions and amplitudes of these reflections. In this paper, we analyzed the echo from the fish by using the sonar signal of the bottlenose dolphin. Firstly, we analyzed echoes which were measured from the anaesthetized fish in a water tank. It was verified that the numbers and delays of reflections are varied with both the species and the tilt angle. Secondary, we analyzed the echo which was measured from the live fish suspended by nylon monofilament line in the open sea. It was verified that the delays and amplitudes of reflections are varied with the orientation and movement of the fish.

    DOI

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  • 音響観測門によるスナメリの地域的行動観測

    木村里子, 赤松友成, 王丁, 王克雄, 李松海

    海洋音響学会   34 ( 4 ) 260 - 265  2007年

    DOI CiNii

  • Sonar gain control in echolocating finless porpoises (Neophocaena phocaenoides) in an open water (L)

    Songhai Li, Ding Wang, Kexiong Wang, Tomonari Akamatsu

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   120 ( 4 ) 1803 - 1806  2006年10月  [査読有り]

    DOI PubMed

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    31
    被引用数
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  • Estimated detection distance of a baiji's (Chinese river dolphin, Lipotes vexillifer) whistles using a passive acoustic survey method

    Kexiong Wang, Ding Wang, Tomonari Akamatsu, Kaoru Fujita, Rika Shiraki

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   120 ( 3 ) 1361 - 1365  2006年09月  [査読有り]

    DOI PubMed

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    19
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  • Feeding behavior of wild dugongs monitored by a passive acoustical method

    Chika Tsutsumi, Kotaro Ichikawa, Nobuaki Arai, Tomonari Akamatsu, Tomio Shinke, Takeshi Hara, Kanjana Adulyanukosol

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   120 ( 3 ) 1356 - 1360  2006年09月  [査読有り]

    DOI PubMed

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    18
    被引用数
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  • Dugong (Dugong dugon) vocalization patterns recorded by automatic underwater sound monitoring systems

    K Ichikawa, C Tsutsumi, N Arai, T Akamatsu, T Shinke, T Hara, K Adulyanukosol

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   119 ( 6 ) 3726 - 3733  2006年06月  [査読有り]

    DOI PubMed

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    38
    被引用数
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  • FISCHOMステレオカメラの立体計測精度の評価

    高橋 秀行, 松田 秋彦, 赤松 友成

    水産工学研究所技報   28 ( 28 ) 85 - 91  2006年03月

    CiNii

  • Acoustic survey of irrawaddy dolphin populations in Chilika lagoon: First test of a compact high-resolution device

    R. Bahl, T. Ura, H. Sugimatsu, T. Inoue, T. Sakamaki, J. Kojima, T. Akamatsu, H. Takahashi, S. K. Behera, A. K. Pattnaik, Muntaz Khan, S. K. Kar

    OCEANS 2006 - Asia Pacific    2006年

     概要を見る

    Irrawaddy dolphins (Orcaella brevirostris) being on top of the food chain are considered as a flagship species of Chilika. These cetaceans produce characteristic echolocation pulses that make them acoustically visible, night or day. Acoustic-based survey methods are found to be indispensable for surveying porpoises and dolphins in coastal precincts. This paper reports the first such collaborative attempt in Chilika by applying acoustic survey technology based on the design of an innovative compact and portable acoustic survey device designed for observation of groups of small cetaceans. The acoustic sensor system is housed in a ©bird-cage© structure containing 3 hydrophones forming a main linear array, together with two more hydrophones forming a small 3-element triangle array with the central hydrophone, in a plane perpendicular to the linear array axis. It weighs 25kg and is 3.6m long, 30cm in diameter, and can be deployed either vertically or horizontally with buoys and a weight. A high-speed multichannel data acquisition system records the dolphin click sounds from all hydrophones. Signal processing algorithms have been developed for automatic detection and discrimination of echolocation clicks from other underwater sounds, localization of sound sources, and tracking individual animals. The device has previously been tested in vertical mode in a quasi-natural environment with a group of bottlenose dolphins that has confirmed its capability to precisely track several vocalizing animals. The depth of the Chilika lagoon in the dolphin habitat can be as shallow as 1.5m. Thus, the array has to be deployed in horizontal mode, which enables it to provide very good lateral resolution in the broadside direction. This paper reports the first results of using this array in shallow water conditions. Movements of several Irrawaddy dolphins have been observed very clearly. ©2006 IEEE.

    DOI

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    17
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  • Stability of call sequence in dugongs' vocalization

    Naoko Okumura, Kotaro Ichikawa, Tomonari Akamatsu, Nobuaki Arai, Tomio Shinke, Takeshi Hara, Kanjana Adulyanukosol

    OCEANS 2006 - Asia Pacific    2006年

     概要を見る

    Dugongs (Dugong dugon) produce different types of vocalization such as chirp, trill, and barks. Previous reports showed that dugongs have two kinds of phonemes: long duration calls (trill) and short duration calls (chirp-squeaks hereinafter called chirp). Especially, the chirp and trill calls were widely reported in different populations. However, characteristics of call patterns in dugongs have never been reported. Moreover, the function of these calls was not revealed. The objective of this study is to classify the vocalization patterns of dugong calls and discuss the stability call sequences within and across local populations of dugongs. We recorded the underwater sound at the off Talibong Island, Trang, Thailand in 2004 and 2005 for 120 hours by an automatic underwater sound recording system (AUSOMS-D, System Intech, Tokyo). The AUSOMS-D is the water resistant stand-alone recording system and developed for passive acoustical monitoring targeting human audible range. The AUSOMS-D consisted of a pair of hydrophones located 2 m apart for calculating the bearings of the sound sources. The electric circuits and batteries were housed in a pressure-resistant case, and the hydrophones were connected to a stereo preamplifier. The sound signals were fed into a 1-kHz high pass filter to eliminate low frequency background noise. Digitized signals were recorded on an 80 GB removable hard disk drive by uncompressed format with a time stamp. The power supply system with batteries and DC/DC converter were also housed inside the case. The sampling frequency of the A/D converter was 44.1 kHz and the dynamic range was 74-120 dB (re 1 μPa) with a 16-bit resolution. Each hydrophone had flat frequency responses within 2 dB between 1 and 10 kHz. For the comparison purpose, we made recording of a captive dugong in Toba Aquarium, Japan, which was introduced from Philippine water. We analyzed the underwater sound data set that was obtained in both animals in different environment and populations. Short duration calls with less than 300 milliseconds were defined as chirp and trill was defined as a call lasting over 300 milliseconds. The end of a call sequence was defined at the silence over 3 seconds. Total of 1174 audible calls were detected from total of 12 hours data set (from 3:50 to 6:50 01-04 March 2004). Chirp were observed more than trill calls (567 chirps and 67 trills). Chirp-tochirp transitions were most frequency observed (81.68%), whereas trill-to-trill transitions were the least (4.27%). Transitions between the two types of calls were also observed (6.98%, 7.07%). Trill appeared in the middle and the end of a call sequence. The position of the trill did not differ between wild individual in Thailand and a captive individual from off Philippine that are considered to be separated populations. The stability of the sequence of each type of calls in a call sequence is investigated. Unlike song of birds or baleen whales, the call sequence pattern of dugong suggests small difference across the populations. The call sequence analysis as well as the behavioral context observation will provide the key to interpret function of dugong calls. ©2006 IEEE.

    DOI

    Scopus

    4
    被引用数
    (Scopus)
  • Acoustic monitoring of echolocating porpoises

    Tomonari Akamatsu, Ding Wang, Kexiong Wang, Songhai Li

    OCEANS 2006 - ASIA PACIFIC, VOLS 1 AND 2     43 - +  2006年  [査読有り]

     概要を見る

    Underwater ultrasonic sound of finless porpoises Neophocaena phocaenoides were monitored concurrent with visual observations in the Yangtze River, China. In a total of 774 km cruise, 588 finless porpoises were sighted by visual observation and 44,864 ultrasonic pulses were recorded. The acoustic monitoring system could detect presence of the finless porpoises 82% of the time. False alarm in the system occurred with a frequency of 0.9%. The high frequency acoustical observation is suggested as an effective method for field surveys of small cetaceans, which produce high frequency sonar signals.

    DOI

    Scopus

  • Origin of the double- and multi-pulse structure of echolocation signals in Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientialis)

    Songhai Li, Kexiong Wang, Ding Wang, Tomonari Akamatsu

    Journal of the Acoustical Society of America   118 ( 6 ) 3934 - 3940  2005年12月  [査読有り]

    DOI PubMed

    Scopus

    23
    被引用数
    (Scopus)
  • Method for underwater measurement of the auditory brainstem response of fish

    Tomohiro Suga, Tomonari Akamatsu, Ryo Kawabe, Tomonori Hiraishi, Katsutarou Yamamoto

    Fisheries Science   71 ( 5 ) 1115 - 1119  2005年10月  [査読有り]  [国際誌]

    DOI CiNii

    Scopus

    1
    被引用数
    (Scopus)
  • A passive acoustic monitoring method applied to observation and group size estimation of finless porpoises

    Kexiong Wang, Ding Wang, Tomonari Akamatsu, Songhai Li, Jianqiang Xiao

    Journal of the Acoustical Society of America   118 ( 2 ) 1180 - 1185  2005年08月  [査読有り]

    DOI PubMed

    Scopus

    47
    被引用数
    (Scopus)
  • Effects of ambient noise on the whistles of Indo-Pacific bottlenose dolphin populations

    Tadamichi Morisaka, Masanori Shinohara, Fumio Nakahara, Tomonari Akamatsu

    Journal of Mammalogy   86 ( 3 ) 541 - 546  2005年06月  [査読有り]

    DOI

    Scopus

    108
    被引用数
    (Scopus)
  • Geographic variations in the whistles among three Indo-Pacific bottlenose dolphin Tursiops aduncus populations in Japan

    Tadamichi Morisaka, Masanori Shinohara, Fumio Nakahara, Tomonari Akamatsu

    Fisheries Science   71 ( 3 ) 568 - 576  2005年06月  [査読有り]

    DOI CiNii

    Scopus

    72
    被引用数
    (Scopus)
  • Echolocation signals of the free-ranging Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientialis)

    Songhai Li, Kexiong Wang, Ding Wang, Tomonari Akamatsu

    Journal of the Acoustical Society of America   117 ( 5 ) 3288 - 3296  2005年05月  [査読有り]

    DOI PubMed

    Scopus

    74
    被引用数
    (Scopus)
  • Off-axis sonar beam pattern of free-ranging finless porpoises measured by a stereo pulse event data logger

    T Akamatsu, D Wang, KX Wang

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   117 ( 5 ) 3325 - 3330  2005年05月  [査読有り]

    DOI PubMed

    Scopus

    32
    被引用数
    (Scopus)
  • Biosonar behaviour of free-ranging porpoises

    Tomonari Akamatsu, Ding Wang, Kexiong Wang, Yasuhiko Naito

    Proceedings of the Royal Society B: Biological Sciences   272 ( 1565 ) 797 - 801  2005年04月  [査読有り]

    DOI PubMed

    Scopus

    108
    被引用数
    (Scopus)
  • Audiogram measurement based on the auditory brainstem response for juvenile Japanese sand lance Ammodytes personatus

    Tomohiro Suga, Tomonari Akamatsu, Kouichi Sawada, Hiroaki Hashimoto, Ryo Kawabe, Tomonori Hiraishi, Katsutaro Yamamoto

    Fisheries Science   71 ( 2 ) 287 - 292  2005年04月  [査読有り]  [国際誌]

    DOI CiNii

    Scopus

    4
    被引用数
    (Scopus)
  • Measurements of auditory sensitivity in common carp Cyprinus carpio by the auditory brainstem response technique and cardiac conditioning method

    KOJIMA TAKAHITO, ITO HIROSUKE, KOMADA TOMOYUKI, TANIUCHI TORU, AKAMATSU TOMONARI

    Fisheries science : FS   71 ( 1 ) 95 - 100  2005年02月

    DOI CiNii

    Scopus

    38
    被引用数
    (Scopus)
  • New stereo acoustic data logger for free-ranging dolphins and porpoises

    Tomonari Akamatsu, Akihiko Matsuda, Shiro Suzuki, Ding Wang, Kexiong Wang, Michihiko Suzuki, Hiroyuki Muramoto, Naoki Sugiyama, Katsunori Oota

    Marine Technology Society Journal   39 ( 2 ) 3 - 9  2005年

    DOI

    Scopus

    55
    被引用数
    (Scopus)
  • 光学・音響複合型魚群観測システムFISCHOMによる人工魚礁蝟集魚群の定量的な観測

    高橋 秀行, 松田 秋彦, 高木 儀昌, 赤松 友成

    日本水産工学会誌   41 ( 3 ) 261 - 265  2005年

     概要を見る

    For quantitative assessments of the effect of artificial reefs to accumulate fish school. we developed a low cost fish school monitoring system (FISCHOM). which enables visual and acoustical observation of fish resources for more than several days. In this paper, we report the profile of prototype FISCHOM and the outcome of trial survey. FISHCOM is consisted of two sensors (a stereo camera with two strobe lights and an echo sounder), a programmable timer, a battery, and a pressure resistant housing with a visually and acoustically transparent window for the sensors. All components except for the housing were selected from inexpensive articles on the market. A digital camera captured two visual images apart 50 cm away each other, which was combined together by a stereo photogrammetric mirror. The stereo images enable us to measure the three-dimensional information of fish school (e.g. fish length tilt angle, distribution). Two sensors acquire a set of data every optional interval (from several seconds to hours) controlled by the programmable timer. A trial survey was carried out at a high-rise artificial reef located off Atsumi, Yamagata prefecture on May 2003. FISCHOM succeeded a 5 days monitoring with an hour interval of data acquisition. We obtained a time series data of individual number of fish, fish length and distance from FISHCOM by the stereo camera, and fish school distribution by the echo sounder. We have demonstrated that the FISCHOM is appropriate to obtain quantitative and continuous data of fish school than other observation methods, which commonly used for the artificial reef assessment, such as observation by SCUBA diver, angling sampling and fish echo sounder operated on a boat.

    DOI CiNii

  • Monitoring dugong feeding behavior in a tidal flat by visual and acoustic observation

    堤 千華, 市川光太郎, 赤松友成, 荒井修亮, 新家富雄, 原 武史

    海洋理工学会誌,Vol.11 No.1.,77-80     37 - 42  2005年  [査読有り]

    CiNii

  • 研究速報「鳴音データの解析によるヨウスコウカワイルカの潜水行動およびバイオソナー特性の推定」

    浦 環, バール ラジェダール, 矢野 正人, 赤松 友成, 王 丁, 王 克雄

    生産研究   56 ( 6 ) 467 - 470  2004年11月

     概要を見る

    特集1 海中工学研究センター

    DOI CiNii

  • Marine mammal echolocation provides a model of forthcoming bio-oriented sonar

    Tomonari Akamatsu, Ding Wang, Kexiong Wang, Yasuhiko Naito

    Ocean '04 - MTS/IEEE Techno-Ocean '04: Bridges across the Oceans - Conference Proceedings   4   2321 - 2322  2004年

     概要を見る

    Cetacean's sonar is an appropriate model of underwater acoustical sensing technology. Sonar behavior of three free-ranging finless porpoises in an oxbow of the Yangtze River was observed by micro data logger systems attached on the animals. Newly developed acoustic data logger could record porpoise's sonar pulse events 1000 times every second with the amplitude information. Close correlation between sonar effort and behavioral context could be observed. Frequent use of sonar with various inter-pulse intervals was recorded during quick body movements characterized by spiky change of heaving acceleration. The inter-pulse intervals were precisely controlled to adjust the distance to a remote target, which was similar to the terminal phase in bat's sonar behavior. © 2004 IEEE.

  • Spotlined sardine Sardinops melanostictus listens to 1-kHz sound by using its gas bladder

    T Akamatsu, A Nanami, HY Yan

    FISHERIES SCIENCE   69 ( 2 ) 348 - 354  2003年04月  [査読有り]

    DOI

    Scopus

    13
    被引用数
    (Scopus)
  • Single-Hydrophone Method for Reconstructing Dynamic Behavior of Endangered Chinese River Dolphin

    赤松 友成, 浦 環

    Proc.Oceans'03,San Diego, USA   1   473 - 477  2003年

    DOI

    Scopus

  • Empirical refinements applicable to the recording of fish sounds in small tanks

    T Akamatsu, T Okumura, N Novarini, HY Yan

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   112 ( 6 ) 3073 - 3082  2002年12月

    DOI PubMed

  • Analyses of small tank acoustics: Empirical and theoretical approaches

    Tsuyoshi Okumura, Tomonari Akamatsu, Hong Y. Yan

    Bioacoustics   12 ( 2-3 ) 330 - 332  2002年01月

    DOI

    Scopus

    29
    被引用数
    (Scopus)
  • Acoustic signals and aggressive conflicts in the skunk loach botia morleti: Integrating sensory and behavioural approaches

    Timothy C. Sparkes, Callie Prater, Tomonari Akamatsu, Hong Y. Yan

    Bioacoustics   12 ( 2-3 ) 257 - 259  2002年01月

    DOI

    Scopus

    4
    被引用数
    (Scopus)
  • Diving behaviour of freshwater finless porpoises (Neophocaena phocaenoides) in an oxbow of the Yangtze River, China

    Tomonari Akamatsu, Ding Wang, Kexiong Wang, Zhuo Wei, Qingzhong Zhao, Yasuhiko Naito

    ICES Journal of Marine Science   59 ( 2 ) 438 - 443  2002年  [査読有り]

    DOI

    Scopus

    57
    被引用数
    (Scopus)
  • A passive acoustical survey method of finless porpoises

    Tomonari Akamatsu, Ding Wang, Kexiong Wang, Zhuo Wei, Yasuhiko Naito

    FISHERIES SCIENCE   68   294 - 297  2002年  [査読有り]

    DOI

    Scopus

    2
    被引用数
    (Scopus)
  • イルカのソナー能力

    赤松 友成

    可視化情報学会誌 = Journal of the Visualization Society of Japan   21 ( 1Supplement ) 139 - 140  2001年07月

     概要を見る

    Dolphins have highly developed sonar abilities and have been studied extensively in captivity. The use of sonar by dolphins and porpoises in the wild is thought to be related to the underwater navigation and searching behavior. Here we report a new and simple method to archive continuous click events individually. Echolocation click events and swimming speed of finless porpoises (Neophocaena phocaenoides) were recorded with data loggers attached on the animals. The echolocation range converted from sonar pulse intervals in open waters ranged up to 130 m. Echolocation of free-ranging dolphins appears to adapt to various distance in navigation or ranging. Silent swim distance, calculated by the swim speed multiplied by the duration of the non-echolocating periods, was smaller than the echolocation range. Finless porpoises are believed to examine their frontal area acoustically using echolocation. In other words, the observed finless porpoises swam without echolocation only in an already inspected area.

    DOI CiNii

  • Comparison between visual and passive acoustic detection of finless porpoises in the Yangtze river, China

    T Akamatsu, D Wang, KX Wang, Z Wei

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   109 ( 4 ) 1723 - 1727  2001年04月

    DOI PubMed

    Scopus

    39
    被引用数
    (Scopus)
  • A method for individual identification of echolocation signals in free-ranging finless porpoises carrying data loggers

    T Akamatsu, D Wang, KX Wang, Y Naito

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   108 ( 3 ) 1353 - 1356  2000年09月

    DOI PubMed

    Scopus

    30
    被引用数
    (Scopus)
  • Echolocation range of captive and free-ranging baiji (Lipotes vexillifer), finless porpoise (Neophocaena phocaenoides), and bottlenose dolphin (Tursiops truncatus)

    T Akamatsu, D Wang, K Nakamura, K Wang

    JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA   104 ( 4 ) 2511 - 2516  1998年10月

    DOI

    Scopus

    97
    被引用数
    (Scopus)
  • イルカの声からわかること

    赤松 友成

    生物物理   38 ( 4 ) 147 - 150  1998年07月

     概要を見る

    Dolphins have bio-sonar ability called echoiocation. Clicks, echolocation signals, provide various biological information, such as, species, target range and acoustical survey effort of dolphins. Acoustical measurement is anewly developed method to observe underwater behavior of vocalizing animals.

    DOI CiNii

  • Gillnet Passive Acoustic Deterrents:Investigating Inter-Reflector Spacings with a Harbor Porpoise Phocoena phocoena

    Nakamura Koji, Akamatsu Tomonari, Goodson A.David, KAGOSHIMA Kenji, SHIMAZAKI Kenji

    Fisheries science : FS   64 ( 4 ) 648 - 649  1998年

    DOI CiNii

    Scopus

    3
    被引用数
    (Scopus)
  • Startle Response Level of Japanese Anchovy Engraulis japonicus to Underwater Pure Tone Signals

    Tomonari Akamatsu, Yoshiki Matsushita, Yoshimi Hatakeyama, Yoshihiro Inoue

    Fisheries Science   62 ( 4 ) 648 - 649  1996年08月

    DOI

    Scopus

    5
    被引用数
    (Scopus)
  • Effects of underwater sounds on escape behavior of Steller sea lions

    T Akamatsu, K Nakamura, H Nitto, M Watabe

    FISHERIES SCIENCE   62 ( 4 ) 503 - 510  1996年08月

    DOI

    Scopus

    6
    被引用数
    (Scopus)
  • エコ-ロケ-ション信号検出テレメトリ-システムの開発とネズミイルカでの測定実験

    赤松 友成

    水産工学研究所研究報告   ( 15 ) p145 - 156  1994年03月

     概要を見る

    記事分類: 農林水産学--水産--水産生物

    CiNii

  • A review of studies on attempts to reduce the entanglement of the Dall's porpoise, Phocoenoides dalli, in the Japanese salmon gillnet fishery

    Y. Hatakeyama, K. Ishii, T. Akamatsu, H. Soeda, T. Shimamura, T. Kojima

    Gillnets and cetaceans     549 - 563  1994年

  • ECHOLOCATION RATES OF TWO HARBOR PORPOISES (PHOCOENA PHOCOENA)

    Tomonari Akamatsu, Yoshimi Hatakeyama, Takahito Kojima, Hideo Soeda

    Marine Mammal Science   10 ( 4 ) 401 - 411  1994年

    DOI

    Scopus

    24
    被引用数
    (Scopus)
  • パルス音がオキゴンドウの逃避行動に及ぼす影響

    赤松 友成, 畠山 良己, 高津 尚之

    日本水産学会誌   59 ( 8 ) 1297 - 1303  1993年08月

    DOI CiNii

    Scopus

    10
    被引用数
    (Scopus)
  • 流し網と魚の超音波反射

    畠山 良己, 赤松 友成

    水産工学研究所技報. 漁業生産   ( 5 ) 15 - 24  1991年03月

    CiNii

  • ハンドウイルカの流し網の認知部分と羅網過程に関する実験

    赤松 友成, 畠山 良己, 石井 憲, 添田 秀男, 嶋村 哲哉, 小島 隆人

    日本水産学会誌   57 ( 4 ) 591 - 597  1991年

    DOI CiNii

    Scopus

    1
    被引用数
    (Scopus)

▼全件表示

書籍等出版物

  • 音響学の展開

    安藤, 彰男, 坂本, 眞一 (熱音響工学)

    コロナ社  2021年09月 ISBN: 9784339013702

  • 生き物と音の事典

    生物音響学会

    朝倉書店  2019年11月 ISBN: 9784254171679

  • 水中生物音響学 : 声で探る行動と生態

    赤松, 友成, 木村, 里子, 市川, 光太郎

    コロナ社  2019年01月 ISBN: 9784339013405

  • 低周波音 : 低い音の知られざる世界

    土肥, 哲也, 赤松, 友成, 新井, 伸夫, 井上, 保雄, 入江, 尚子, 時田, 保夫, 中, 右介, 町田, 信夫, 山極, 伊知郎

    コロナ社  2017年11月 ISBN: 9784339013368

  • Listening in the ocean : new discoveries and insights on marine life from autonomous passive acoustic recorders

    Au, Whitlow W. L., Lammers, Marc O.

    Springer  2016年 ISBN: 9781493931750

  • The effects of noise on aquatic life II

    International Conference on the Effects of Noise on Aquatic Life (3rd : 2013), Popper, Arthur N., Hawkins, A. D. (Anthony Donald)

    Springer  2016年 ISBN: 9781493929801

  • エアロアクアバイオメカニクス : 生きものに学ぶ泳ぎと飛行のしくみ

    エアロ・アクアバイオメカニズム研究会

    森北出版  2010年08月 ISBN: 9784627947313

  • Bulletproof feathers : how science uses nature's secrets to design cutting-edge technology

    Allen, R. (Robert)

    University of Chicago Press  2010年 ISBN: 9780226014708

  • Bio-mechanisms of swimming and flying : fluid dynamics, biomimetic robots, and sports science

    加藤, 直三, 上村, 慎治

    Springer  2008年 ISBN: 9784431733799

  • Handbook of signal processing in acoustics

    Havelock, David, 桑野, 園子, Vorländer, Michael

    Springer  2008年 ISBN: 9780387776989

  • 海洋動物の音響観測 : 声を利用した海洋生物の音響観測部会報告書

    海洋音響学会

    海洋音響学会  2006年05月

  • Echolocation in bats and dolphins

    Thomas, Jeanette A., Moss, Cynthia F., Vater, Marianne

    University of Chicago Press  2003年 ISBN: 0226795993

  • 動物たちの気になる行動

    上田, 恵介, 佐倉, 統

    裳華房  2002年05月 ISBN: 4785387432

  • イルカ類の感覚と行動

    添田, 秀男

    恒星社厚生閣  1996年10月 ISBN: 476990830X

  • イルカはなぜ鳴くのか

    文一総合出版  1996年

  • Sensory Systems of Aquatic Mammals

    Kastelein, Ron, J., Thomas, Jeanette A., Nachtigall, Paul E.

    De Spil Publishers  1995年 ISBN: 9072743059

  • Marine mammal sensory systems

    Thomas, Jeanette A., Kastelein, Ronald A., Supin, Alexander Ya, Symposium on Sensory Systems of Aquatic Mammals

    Plenum Press  1992年 ISBN: 0306443511

▼全件表示

共同研究・競争的資金等の研究課題

  • サンゴ礁生態系の変動を生物音で観測する

    日本学術振興会  科学研究費助成事業 基盤研究(A)

    研究期間:

    2017年04月
    -
    2020年03月
     

    赤松 友成, Lin TzuHao, フレデリック シニゲル, 波利井 佐紀, 御手洗 哲司

     概要を見る

    約二年間にわたる長期水中音データを琉球大学の共同研究者とともに取得し、開発したアルゴリズムでの音響分類をすすめた。CRESTフィールドキャンペーンと密に協力しながら、サンゴ礁域での音響分類を行った。長期連続運用可能なSound Trapへの録音機材の置き換えをすすめ、潜水作業の負担軽減に努めた。
    サンゴ礁での水中生物音響のベースラインデータが取得された。ただし研究機関終了後も見据えて長期観測体制の維持を検討している。また、サンゴ礁との比較水域として、多様性に富むアマゾン川や船舶騒音が激しいイスタンブール海峡などのデータも協力者から取得済または予定である。次年度、比較解析を行うことで、サンゴ礁のサウンドスケープの特性について明らかにする。
    本年度より研究チームに参画した海洋研究開発機構の研究協力者により機械学習を用いた音源分離や音素の自動分類のアルゴリズム開発が進んだ。まだ十分ではないが、教師なしで生物音と人工的な騒音の分離を試みており、とくに周期的にみられる魚類のコーラスに関しては自動分類精度が上がっている。
    成果の普及と騒音影響の総括のためオーシャンノイズ・アジアという国際シンポジウムを函館で開催した。北海道大学の協力を得て、約100名の参加があり、うち半数が海外からであった。音響解析手法や環境影響評価への応用など、当該分野における最先端の知見を得ただけでなく、当プロジェクトの国際的な認知向上にも役立った。

  • 水中低周波音の新しい校正手法の開発

    日本学術振興会  科学研究費助成事業 挑戦的萌芽研究

    研究期間:

    2016年04月
    -
    2020年03月
     

    赤松 友成

     概要を見る

    手軽な低周波音校正手法を確立し、最終年度として研究を取りまとめるとともに、開発技術を資源探査や生物資源モニタリングに応用できることを実証した。
    低周波音校正のまとめとして、米国製、ニュージーランド製、日本製の異なる自動録音装置を対象に、比較校正を行った。校正水域として選定した本栖湖で感度校正を行い、静穏なプラットフォームから各機材を吊り下げて送受信実験を行い、それぞれの特性が明らかになった。米国製機材は感度が悪く、大音圧の生物ソナー音の記録に特化していた。ニュージーランド製の機材は中程度の感度で、堅牢なつくりのため運用も容易であった。日本製の機材はもっとも感度が高く魚類の鳴音録音に適していたが、圧縮形式の録音であり受信周波数帯域の上限がほかの機材に比べ劣っていた。音響機材の実際の性能はこれまで専門の機関でしか得られなかったが、本研究で感度校正を簡便に行えるようになったため、今後の海中騒音計測に役立つ成果が得られた。
    本研究成果を実際の海洋騒音問題に役立てるため、主要な海洋騒音源である資源探査用発音装置の音圧計測を行った。海底資源探査では巨大な低周波音源により海底下の資源分布を調べている。しかし高圧空気を開放するため大音量の不要な高周波成分が発せられ、海洋生物への影響が懸念されている。高周波成分を抑えた狭帯域低周波音源は今後の活用が見込まれるため、その校正実験をアイスランドで実施した。防水型の小型録音機を基準受信機として用いたため、野外のあらゆる場所で暴露音圧計測を行うことができた。

  • ネズミイルカの漁業との競合実態の解明

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    研究期間:

    2014年04月
    -
    2017年03月
     

    松石 隆, 松田 純佳, 黒田 実加, 松井 菜月, 前田 彩貴, 桜井 憲二, 赤松 友成

     概要を見る

    ネズミイルカは沿岸に生息する鯨類で,人間活動の影響を強く受ける。欧米では多くの研究がなされているが,日本での研究は皆無に近い。近年,鯨類の漂着・混獲情報収集体制整備や音響観測技術の普及によって,ネズミイルカに関する新たな研究の展開が可能となった。本研究では,ネズミイルカの漂着・混獲から得られる標本を用いて,ネズミイルカの食性を解析し,漁業資源への捕食実態を明らかにした。また,音響観測技術を利用して,漁網近傍におけるネズミイルカの行動を記録し,混獲メカニズムの一端を解明した。これにより、ネズミイルカの漁業との競合実態の一端が明らかになり,鯨類と人類との共存の一助となる知見を得た。

  • 海洋生物の遠隔的種判別技術の開発

    独立行政法人科学技術振興機構  戦略的創造研究推進事業

    研究期間:

    2011年
    -
    2016年
     

  • 船舶騒音が海棲哺乳類の生態に与える影響についての研究

    日本学術振興会  科学研究費助成事業 挑戦的萌芽研究

    研究期間:

    2013年04月
    -
    2015年03月
     

    梅田 直哉, 赤松 友成, 増山 豊, 櫻田 顕子, 国枝 佳明, 鵜山 久, 森 恭一, 谷口 和義, 池上 忠茂, 菅原 茂, 三井 宏

     概要を見る

    日本列島南方において大型帆船により、石川県能登島周辺海域において小型帆船と小型動力船により、曳航した音響センサーを用いて、海棲哺乳類の船舶騒音に対する反応行動を調査した。前者では対象生物との遭遇率が不十分で有意なデータとならず計測システムの検証にとどまったが、後者ではミナミハンドウイルカの群れの反応を頻繁に計測、記録することができた。この解析の結果によると、イルカの反応には、低速かつ低プロペラ荷重度の動力船と帆走中の帆船では顕著な違いは確認されなかった。これより本調査の範囲では、船舶騒音がイルカに悪影響を与えるという事実は定量的に確認されなかった。

  • 音響バイオロギングによる大型ヒゲクジラの摂餌行動の研究

    日本学術振興会  科学研究費助成事業 基盤研究(B)

    研究期間:

    2012年04月
    -
    2015年03月
     

    赤松 友成

     概要を見る

    水産資源の持続的な利用のためには、ヒゲクジラ類の大きな捕食圧力は無視できない。しかし、ヒゲクジラの摂餌量と餌種は、これまで捕獲による胃内容物調査でしか得られなかった。本研究により、大型鯨類二種すなわちシロナガスクジラとザトウクジラの摂餌行動を音響バイオロギングにより直接計測できるようになった。また水中運動の三次元再構成を行い、摂餌行動中の体の動きも明らかにした。記録された鳴音の解析により、鳴音発声頻度と音源音圧レベルを明らかにし、国際誌に掲載された。

  • “フィールドミュージアム”構想によるアマゾンの生物多様性保全

    JST/JICA  地球規模課題対応国際科学技術協力(SATREPS)

    研究期間:

    2014年
    -
    2015年
     

  • 沿岸性鯨類スナメリの保全のための個体数推定法の改良と個体数変遷の評価

    日本学術振興会  科学研究費助成事業 基盤研究(B)

    研究期間:

    2009年
    -
    2011年
     

    白木原 國雄, 赤松 友成, 北門 利英, 天野 雅男, 白木原 美紀

     概要を見る

    沿岸域に生息し人間活動の影響を受けやすい小型鯨類スナメリの保全のためには個体数のモニタリングが必要である.個体数は目視調査により推定されてきたが,従来は推定の難しい発見確率を100%と仮定していた.音響(鳴音収録)調査と目視調査を併用して発見確率を推定する方法を開発した. 2010年に長崎県大村湾の個体数をセスナからの目視調査により推定したが,ここ10年間の個体数減少は検出できなかった.

  • イルカ型対象判別ソナーの開発

    新技術・新分野創出のための基礎研究推進事業

    研究期間:

    2007年
    -
    2011年
     

     概要を見る

    イルカ型広帯域ソナーを模倣した対象判別機能をもつソナーの開発

  • 加速度エソグラム作成による動物行動計量分析

    日本学術振興会  科学研究費助成事業 基盤研究(A)

    研究期間:

    2007年
    -
    2010年
     

    佐藤 克文, 島谷 健一郎, 依田 憲, 渡辺 伸一, 高橋 晃周, 坂本 健太郎, 赤松 友成, 高橋 晃周, 坂本 健太郎, 赤松 友成

     概要を見る

    加速度時系列データから簡便にスペクトログラムを作成し、k-means法による自動判別を行い,いくつかの行動にカテゴライズするソフトウェアーEthographerを作成した。本ソフトを用いることで、複数種類の対象動物から得られた加速度時系列データを簡単に解析する事が可能となり、対象動物毎の生理・生態学上の発見に加えて,種間比較による研究成果が得られた。

  • ヨウスコウカワイルカ保全のための揚子江全域音響調査

    日本学術振興会  科学研究費助成事業 基盤研究(B)

    研究期間:

    2007年
    -
    2010年
     

    赤松 友成

     概要を見る

    本研究では、最新の水中音響技術を危機的な状況にある淡水イルカに適用することで、揚子江全域でのマクロスケールな分布と生息密度の高い水域でのミクロスケールな分布が明らかになった。ヨウスコウカワイルカおよびヨウスコウスナメリの本来の歴史的な分布域である三峡ダム下流の宜昌市から上海市までの流域1500kmを、動物の発する声を受信する曳航式水中マイクロホンにより探査したところ、ヨウスコウカワイルカの絶滅宣言に至り、ヨウスコウスナメリの危機的な減少が明らかになった。揚子江中流域の生息密度の高いホットスポットにおいては、定点型観測機器を用いて長期観測を行い、音響検出を生息密度に換算する手法を編み出すとともに、重点的な曳航調査を行い精密な分布地図を明らかにした。現在では、揚子江の中下流域武漢市から上海市までの1100kmで貨物船を用いた自動音響調査を実施し、ローコストで広域分布データを定期的に取得している。これらの手法は、今日では世界各国の小型鯨類観測に応用され始めた。

  • 音響データロガーによるジュゴンモニタリングネットワークの構築

    日本学術振興会  科学研究費助成事業 萌芽研究

    研究期間:

    2004年
    -
    2006年
     

    荒井 修亮, 守屋 和幸, 赤松 友成, 畔上 修一

     概要を見る

    ジュゴンは草食性の海生ほ乳類(海牛類)で熱帯から亜熱帯の沿岸域に生息する。我が国の沖縄本島周辺はジュゴン生息の北限と言われており、同海域に生息するジュゴンは生物学上非常に重要な希少種である。このため、生息頭数の確認(環境省)、漁業による混獲の回避と餌場である海草群落の保護・培養(水産庁)等、国を挙げての対策が講じられている。しかし、既に沖縄海域では10頭未満の生息頭数と言われており、講じる対策の生物学的根拠の調査すら危ぶまれている現状である。
    我々はこうした緊急を要する事態に対して、ジュゴンの生態を直接観察可能なタイ国沿岸にフィールドを求めた。そして、特に漁業による事故死を未然に防止するためのジュゴンモニタリングシステムを、ジュゴンの鳴音を長期間記録する音響データロガーシステムによって構築することを目的とする。
    平成18年度には次の項目について研究を実施した。
    2006年11月にタイ国トラン県リボン島周辺海域において、AUSOMS-Dによるジュゴン鳴音の連続観測並びに海草藻場における摂餌痕(ジュゴン・トレール)の調査と摂餌音の連続録音を行った。合わせて、目視によるジュゴン観測を実施した。AUSOMS-Dの録音データ解析から、ジュゴン鳴音並びに摂餌音のモニタリングが可能であることが分かった。

  • 海洋高次捕食動物プラットフォームによる3次元海洋計測・環境動態監視システムの開発

    日本学術振興会  科学研究費助成事業 基盤研究(A)

    研究期間:

    2003年
    -
    2006年
     

    佐藤 克文, 荒井 修亮, 赤松 友成, 綿貫 豊, 坂本 亘, 高橋 晃周, 内藤 靖彦

     概要を見る

    小型の電子記録装置を動物に搭載するバイオロギング手法は,水生動物の生息域を大きく左右する海洋環境を把握するのに有効な手法となりうる.本プロジェクトでめざしたのは,動物の行動を周辺環境と共にモニタリングする新しい手法を開発することであった.熱帯から南極域に至る広範囲で野外調査を実施した.対象動物もまた,魚類・爬虫類・海鳥類・海産哺乳類と多岐にわたった.
    例えば,ベーリング海に浮かぶセントジョージ島で繁殖を行うハシブトウミガラスは,子育て期間中に周辺海域で餌取りを目的として潜水行動を行うが,彼らの潜水深度が現場の水温躍層と深い関係を有することが判明した.鉛直混合が進んだ海域で潜水を行う場合,彼らは深度80m前後の潜水を繰り返して餌を捕獲していた.ところが,水温躍層がある海域においては,水温躍層をめざした潜水を繰り返し行っていた.水温躍層によって,彼らの餌となる小魚類の滞在深度が左右され,それに対応して高次捕食動物のハシブトウミガラスは潜水深度を選択していたと解釈できる.
    別の例では,ドイツ南極基地周辺で行われたウェッデルアザラシ調査において,アザラシに搭載したカメラによって得られた画像から,南極海の厚さ150mの棚氷の下面に刺胞動物のような固着性生物が高密度に分布することが初めて明らかになった.近年の地球温暖化により,南極海の棚氷が広範囲にわたって崩壊する事が報告されている.棚氷の崩壊により,下面に付着する高密度の動物,およびその周辺に形成される生態系もまた崩壊している事を示唆するものである.
    数々のフィールド調査と個々の具体的成果より,海洋高次捕食動物は海洋環境モニタリングのプラットフォームとして有効であり,動物搭載型の各種小型記録計は動物自身の行動や生理を,周辺環境に照らし合わせて解釈するのに大いに役立っことが明らかとなった.

  • イルカ型ソナーをモデルとした次世代魚群探知技術の研究

    新技術・新分野創出のための基礎研究推進事業

    研究期間:

    2002年
    -
    2006年
     

     概要を見る

    イルカのソナー行動に学んだ新しい水中探査技術の研究

  • 鯨類観測AUVの研究開発

    日本学術振興会  科学研究費助成事業 基盤研究(A)

    研究期間:

    2002年
    -
    2004年
     

    能勢 義昭, 浦 環, 浅田 昭, 柳澤 政生, 小島 淳一, 赤松 友成, 藤井 輝夫, 浅川 賢一

     概要を見る

    鯨類の観測は船舶を用いた計量が主だが、近年は、小型無線機やARGOS衛星を利用した調査あるいは小型データローガーを鯨類に直接装着する方法による調査もおこなわれている。しかし、無線等では海表面にいる鯨類の観測は可能だが海中は観測できない。データローガーは、海面および海中での観測が可能だが鯨類に装着する必要があり、回収率が低いなどの問題がある。つまり、広い海域を高速で移動する大型鯨類の水中観測は困難である。
    本研究では、高速潜航性能に優れ雑音の少ない自律型海中ロボット(AUV : Autonomous Underwater Vehicle)を利用して、海中を移動する鯨類の身体に触れることなく観測できる新しい移動型観測プラットフォームを提案し、実海域実験を通じてその有効性を証明した。
    鯨類の多くは鳴音を出す。雄のザトウクジラの鳴音は複雑なフレーズを形成しており、マッコウクジラの鳴音はクリック音と呼ばれる。本研究では、それぞれの鯨類に特有な鳴音をそれに適合した手法で解析し、その音響特性を利用して、まったくパッシブな方法で音源を特定する小型音響装置を開発し、これをAUVなどに装着して展開、鯨類の位置情報(方位、深度)を得ることで、個体識別および個体数などのデータを取得する、というシステムを開発した。
    具体的には、マッコウクジラについては、小笠原海域で2002年から実験を開始、最終年度の2004年の実験では、AUVによるマッコウクジラの追跡ソフトを起動することができ、実験後のデータ解析により、AUVによるクジラの追跡が十分可能であることが証明された。ザトウクジラについては、鳴音モデルを開発し、データサンプルによるテストで85%以上の確率で同一個体の識別が可能となった。今後は本モデルを小型デバイス化しAUVに搭載し、実海域で展開実験をおこなっていくことが求められる。また、小型歯鯨類であるカワイルカ類の音響観測も本研究に端を発して開始した。
    今後は、本研究で開発した鯨類の3次元的観測システムを小笠原海域などで4次元的におこなうことを提案したい。

  • 水産有用魚種の超音波聴覚と反応行動に関する研究

    日本学術振興会  科学研究費助成事業 若手研究(B)

    研究期間:

    2002年
    -
    2003年
     

    赤松 友成

     概要を見る

    超音波聴覚を有する魚類が近年発見され,水産資源探査用の超音波が,魚群を威嚇し,資源量の過小推定を引き起こす可能性が指摘されていた。そこで,我が国沿岸に生息する水産有用魚種の超音波聴覚を音刺激に対する魚類頭頂部への誘発電位(聴性脳幹反応)を利用して計測し,音響資源計測における魚類行動への潜在的な影響を調べた。
    超音波領域における聴覚の確認実験を行うため,低周波音の再生に適した現有の聴性脳幹反応計測システムに,超音波対応の小型のトランスデューサーを加え,水中で超音波の再生ができるよう改造した。また,大型魚での実験を容易にするため,電極を魚類頭部に接着し絶縁して,水中においても聴性脳幹反応の記録ができる技術を開発した。さらに,超音波領域まで良好な増幅特性を有するパワーアンプと,超音波再生用のトランスデューサーを組み合わせて,超音波暴露実験が可能なシステムを構築した。
    このシステムを用いて,マイワシ,カタクチイワシ,イカナゴ,マコガレイで超音波聴覚を計測した。いずれの種類も,低周波音に感度があったが,超音波は感受しなかった。このため,超音波聴覚はニシン科魚類のなかでも限定的な種に存在する可能性が示唆された。
    なお,マコガレイを除く上記の魚種においては,これまで聴覚感度そのものが未計測であったため,新しい知見を得た。すなわち,マイワシは海産魚のなかでは比較的高い1kHzで感度が良く,音波を鰾で感受していた。イカナゴは,数百Hzの低周波領域を聴くことができるが,聴覚感度は低いことが明らかになった。この研究の副産物として,水中における聴性脳幹反応の計測手法が確立された。この手法を応用すれば,稚魚から大型魚までの様々な魚の聴覚感度を,船上の水槽や生け簀などの現場環境で計測できると期待される。

  • ハンドウイルカの群れ構造と行動生態の解析のためのモニタリング手法の開発-気球を用いた上空からの群れ撮影とソノブイによる鳴音連続収録-

    日本学術振興会  科学研究費助成事業 基盤研究(B)

    研究期間:

    1998年
    -
    2000年
     

    白木原 国雄, 古澤 昌彦, 石松 隆和, 粕谷 俊雄, 赤松 友成

     概要を見る

    天草通詞島の周辺海域あるいは長島海峡に現れるハンドウイルカを対象として,上空から群れの撮影を行う気球システム、ソノブイによる鳴音連続収録システム,群れの音響的追跡手法の開発を試みた.さらに水中マイクロホンによる鳴音収録,測量機器のセオドライトを用いた群れの出現位置の計測,群れの写真撮影および群れの行動観察を行った.
    気球システムは実用化のレベルに達した.このシステムを運搬できる範囲に鯨類が出現するという条件が満たされれば,他の鯨類にも適用可能である.ソノブイを用いた鳴音収録に関して,24時間連続収録が可能となるなど,システムの進展が見られた.1台のソノブイの探知距離は現状では数100mであるが,多くのソノブイを複数の地点に昼夜を問わず置くことができれば,群れの1日の行動圏の把握と群れの1日の行動や生活の把握が期待できるレベルに達した.本研究では複数のモニタリング手法を組み合わせたハンドウイルカの行動生態調査を試みた.
    気球システムから得られた群れ画像を用いて,出生率を年あたり2.1%以上,出産盛期を春から秋と推定した.ソノブイより群れの鳴音を連続的に収録できた.水中マイクロホンによる鳴音収録から,ハンドウイルカは数m先を音響探査することもあれば,200m程度先を探すこともあることが分かった.セオドライト観測から,群れは概して朝方に通詞島の東の海域に出現し,昼間に島の北側に滞在し,夕方に島の西の海域に移動することを明らかにした.群れの行動観察から,概して朝夕に活発に活動するのに対し,昼間は特定の場所に停滞し,水上行動をほとんど示さずに潜水・浮上を繰り返すことが多いことが分かった.識別個体の撮影履歴データを用いて,識別可能個体の死亡率を年あたり3.4%と推定した.また1994年から98年まで個体数は200頭前後で年々ほぼ安定していた.

  • 生物ソナー, その工学的応用の検討

    日本学術振興会  科学研究費助成事業 基盤研究(B)

    研究期間:

    1997年
    -
    1998年
     

    渡辺 好章, 中村 敏明, 福島 正忠, 赤松 友成, 松村 澄子, 力丸 裕, 三橋 渉, 蜂屋 弘之, 奥島 基良

     概要を見る

    本課題では,コウモリやイルカのエコーロケーションについて実際の生態観測を行う機会が少ない工学分野の研究者と,逆にエコーロケーションの仕組みについて興味はあるものの物理的側面からのアプローチへの手がかりがつかみにくい動物行動学を専門とする研究者が共同して観測を体験することによってそれぞれの立場からの総合的な検討を行うことを一つの大きな目的とした.各分担者は,扱う生物の種類によって,主としてイルカを扱うグループとコウモリを扱うグループの2班に分かれて通常の活動を行った.それぞれの研究成果ならびに検討課題については,インターネットを活用し,ネット上での意見交換ならびに討論を研究者相互間で広く行うこととして,お互いの情報を得やすい環境を整備した.しかしながら,離れた場所における意見交換ではその限界もあるため,全員が集合する会議を合計5回開催し,討論の充実を図ると共に本課題の大きな目的の一つに挙げているエコーロケーションの共同観察も全体会議と2回併催して大きな知見を得ることができた.
    これらの観測から考えると,生物ソナーは我々が現在実現している人工ソナーに比べて装置の小型さ,処理能力,柔軟度等その総合能力は格段に高いと認めざるを得ない.特に脳内におけるエコーの信号処理は我々が通常行っている視覚情報処理手法と比べて,時間情報をうまく利用しているという点で学ぶべき事項が多い.すなわち,彼らの脳内においては,時間周波数空間のいわゆるソナグラム的情報処理が末梢ならびに中枢で瞬時に行われ,その結果から周囲環境情報を得ていると考えられる.ヒトの聴覚に関する信号処理手法も近年注目されつつあるが,生物ソナーの工学的な応用への側面からも,今回の成果をふまえて,工学,動物学ならびに生理学などを包含した生物の聴覚信号処理のより一層の総合的な研究の展開が期待される.

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