A5040375490- Marine animal studies overview
- Underwater Acoustics Research
- Animal Vocal Communication and Behavior
- Underwater Vehicles and Communication Systems
- Arctic and Antarctic ice dynamics
- Marine and fisheries research
- Water Quality Monitoring Technologies
- Fish Ecology and Management Studies
- Coral and Marine Ecosystems Studies
- Cephalopods and Marine Biology
- Ichthyology and Marine Biology
- Identification and Quantification in Food
- Cryospheric studies and observations
- Ocean Acidification Effects and Responses
- Maritime Navigation and Safety
- High-pressure geophysics and materials
- Diamond and Carbon-based Materials Research
- Semiconductor Lasers and Optical Devices
- Nonlinear Optical Materials Studies
- Speech and Audio Processing
- Fish Biology and Ecology Studies
- Seismology and Earthquake Studies
- Bat Biology and Ecology Studies
- Spectroscopy and Chemometric Analyses
- Marine and coastal plant biology
Waseda University
2025
Japan Fisheries Research and Education Agency
2012-2024
Institute for International Policy Studies
2020-2024
University of Electro-Communications
2024
Biodiversity Research Center, Academia Sinica
2023
The Ocean Foundation
2021
Acoustical Society of America
2007-2020
Interacoustics (Denmark)
2020
Research Center for Information Technology Innovation, Academia Sinica
2018
Japan Science and Technology Agency
2012-2016
The Yangtze River dolphin or baiji ( Lipotes vexillifer ), an obligate freshwater odontocete known only from the middle-lower system and neighbouring Qiantang in eastern China, has long been recognized as one of world's rarest most threatened mammal species. status not investigated since late 1990s, when surviving population was estimated to be low 13 individuals. An intensive six-week multi-vessel visual acoustic survey carried out November–December 2006, covering entire historical range...
Within the set of risk factors that compromise conservation marine biodiversity, one least understood concerns is noise produced by human operations at sea and from land. Many aspects how other forms energy may impact natural balance oceans are still unstudied. Substantial attention has been devoted in last decades to determine sensitivity mammals—especially cetaceans pinnipeds—and fish because they known possess hearing organs. Recent studies have revealed a wide diversity invertebrates...
Many underwater bioacoustical recording experiments (e.g., fish sound production during courtship or agonistic encounters) are usually conducted in a controlled laboratory environment of small-sized tanks. The effects reverberation, resonance, and tank size on the characteristics recorded inside small tanks have never been fully addressed, although these factors known to influence recordings. In this work, 5-cycle tone bursts 1-kHz were used as test signal investigate 170-l rectangular glass...
Raman spectra of diamondlike amorphous carbon (a-C) films prepared under atmosphere with various hydrogen gas content have been measured as a function excitation wavelength. The spectral profiles vary wavelength depending on electronic absorption associated π-π* transitions. Dependence is interpreted in terms resonant scattering from aromatic rings sizes rather than polyene chains. relative intensity 1400 cm−1 band against 1530 found to decrease an increase sp3 a-C films. It shown that the...
It is obvious, at least qualitatively, that small animals move their locomotory apparatus faster than large animals: insects wings invisibly fast, while birds flap slowly. However, quantitative observations have been difficult to obtain from free-ranging swimming animals. We surveyed the behaviour of ranging 0.5 kg seabirds 30 000 sperm whales using animal-borne accelerometers. Dominant stroke cycle frequencies specialist and marine mammals were proportional mass −0.29 ( R 2 =0.99, n =17...
Communication among animals should use signals that are most efficient in their particular habitat. Here, we report data from 3 populations of Indo-Pacific bottlenose dolphins (Tursiops aduncus) Japan produce whistles transmitted efficiently through environmental ambient noise. We compared the characteristics noise dolphins' habitats and produced. In with less noise, produced at varying frequencies greater modulations; when was greater, lower fewer frequency modulations. Examination our...
Detecting objects in their paths is a fundamental perceptional function of moving organisms. Potential risks and rewards, such as prey, predators, conspecifics or non-biological obstacles, must be detected so that an animal can modify its behaviour accordingly. However, to date few studies have considered how animals the wild focus attention. Dolphins porpoises are known actively use sonar echolocation. A newly developed miniature data logger attached porpoise allows for individual recording...
The interclick intervals of captive dolphins are known to be longer than the two-way transit time between dolphin and a target. In present study, free-ranging baiji, finless porpoises, bottlenose in wild captivity were compared. click open waters ranged up 100–200 ms, whereas order 4–28 ms. Echolocation appears adapt various distance navigation or ranging, sometimes 140 m. Additionally, difference waveform characteristics clicks species was recognized frequency maximum energy duration.
Raman spectra of diamondlike amorphous carbon (a-C) films prepared by the sputtering method have been measured as a function excitation wavelength. The spectral profiles vary sensitively, reflecting change absorption associated with π-π* electronic transitions hydrogen content films. From comparison between and spectra, it is confirmed that variation wavelength due to resonant scattering from π-bonded (sp2) clusters.
Author Posting. © Oceanography Society, 2011. This article is posted here by permission of Society for personal use, not redistribution. The definitive version was published in 24, no. 2 (2011): 174–181, doi:10.5670/oceanog.2011.37.
Abstract This study presents bioacoustic recordings in combination with movements and diving behavior of three free‐ranging harbor porpoises (a female two males) Danish waters. Each porpoise was equipped an acoustic data logger (A‐tag), a time‐depth‐recorder, VHF radio transmitter, satellite transmitter. The units were programmed to release after 24 or 72 h. Possible foraging occurred mostly near the surface at bottom dive. showed individual diversity biosonar activity (<100 >50,000...
Abstract The Yangtze finless porpoise ( Neophocaena asiaeorientalis ) is an endangered freshwater subspecies unique to the River basin. Seasonal variations in local distribution of animal, as well fish presence, sand dredging, ship navigation, and bridges were examined potential factors affecting occurrence animals. Passive acoustic surveys performed regularly from May 2007 August 2010, near conjunction Poyang Lake. porpoises was seasonally site‐specific. In August, animals detected more...
A growing demand for sustainable energy has led to an increase in construction of offshore windfarms. Guishan windmill farm will be constructed the Pearl River Estuary, China, which sustains world’s largest known population Indo-Pacific humpback dolphins (Sousa chinensis). Dolphin conservation is urgent issue this region. By using passive acoustic monitoring, a baseline distribution data on species Estuary during pre-construction period had been collected. biosonar detection and its diel,...
Information on the habitat use of critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is critical for its conservation. The diel biosonar behavior in port areas River was examined along with simultaneous observations fish density and boat traffic. Biosonar pulses from porpoises were detected 1233 min (5.77%) over a 21,380 duration effective observations. In total, 190 (5.63%) buzzes (an indication prey capture attempts) recorded among 3372 identified...
This paper describes the high-frequency echolocation signals from free-ranging Yangtze finless porpoise in Tian-e-zhou Baiji National Natural Reserve Hubei Province, China. Signal analysis showed that clicks are typical narrow-band (relative width of frequency spectrum Q = 6.6 +/- 1.56, N 548) ultrasonic pulses. The peak frequencies range 87 to 145 kHz with an average 125 6.92 kHz. durations 30 122 micros 68 14.12, as. characteristics similar those other members Phocoenidae as well distantly...
The detection performance regarding stationary acoustic monitoring of Yangtze finless porpoises Neophocaena phocaenoides asiaeorientalis was compared to visual observations. Three stereo data loggers (A-tag) were placed at different locations near the confluence Poyang Lake and River, China. presence number determined acoustically visually during each 1-min time bin. On average, detected 81.7±9.7% entire effective observation time, while animals confirmed 12.7±11.0% time. Acoustic indicated...
Abstract During the Yangtze Freshwater Dolphin Expedition 2012, finless porpoises ( Neophocaena asiaeorientalis ) were acoustically monitored in 9 port areas at night. 6566 min of nocturnal monitoring, porpoise sonar was detected for 488 (7.43% total time). Of all 81 encounters, longest echolocation span obtained 102.9 min, suggesting frequent and prolonged occupation areas. A combined 2091 click trains recorded, with 129 (6.2%) containing minimum inter‐click intervals (ICIs) below 10 ms...