Relationship of swim-bladder shape to the directionality pattern of underwater sound in the oyster toadfish

1998 ◽  
Vol 76 (1) ◽  
pp. 134-143 ◽  
Author(s):  
John F Barimo ◽  
Michael L Fine
Keyword(s):  
Sound Source ◽  
Sound Pressure ◽  
Sound Production ◽  
Swim Bladder ◽  
Underwater Sound ◽  
York River ◽  
Coefficients Of Variation ◽  
Source Level ◽  
Oyster Toadfish ◽  
Relationship Of

The swim bladder of the oyster toadfish, Opsanus tau, has a distinctive heart shape with two anterior protrusions separated by a midline cleft. The lateral surfaces contain intrinsic muscles that meet at the caudal midline, but the rostromedial surface is muscle-free. We hypothesize that swim-bladder design represents a compromise between opposing tendencies toward (i) an omnidirectional sound source that would optimize a male's opportunity to attract females from any direction, and (ii) a directional sound source that would shield the nearby ears during sound production. To determine if the directionality of toadfish sound is consistent with this hypothesis, boatwhistle advertisement calls of individually identified males were recorded in the York River, Virginia, by means of two calibrated hydrophones and a waterproof recording system: one hydrophone was fixed 1 m in front of the fish and the second was roving. Boatwhistles in the horizontal plane propagated in a modified omnidirectional pattern that was bilaterally symmetrical. The mean sound pressure was 126 dB re: 1 µPa at 0°. The sound pressure level decreased by approximately 1 dB at ±45°, after which levels increased to 180°, averaging 3-6 dB greater behind (mean 130 dB) than directly in front of the fish. This pattern is consistent with the hypothesis that sound energy is reduced at the fish's ears. The source level and fundamental frequency of the boatwhistle were highly stereotyped, with coefficients of variation averaging less than 1%, and duration was more variable, with a coefficient of variation of 8%. Grunt levels overlapped but were slightly lower than boatwhistle values.

The Response of the Swim Bladder of the Goldfish (Carassius Auratus) to Acoustic Stimuli

1974 ◽  
Vol 60 (2) ◽  
pp. 295-304
Author(s):  
ARTHUR N. POPPER
Keyword(s):  
Sound Pressure ◽  
Sound Production ◽  
Broad Band ◽  
Coupled System ◽  
Wide Band ◽  
Limiting Factor ◽  
Swim Bladder ◽  
Phase Measurements ◽  
Goldfish Carassius Auratus ◽  
Sound Pressure Levels

1. Sound-pressure levels were measured in the swim bladder of the goldfish using a probe microphone. Measurements of pressure and phase were made relative to the sounds immediately outside of the fish. 2. Results showed that the response of the swim bladder is flat from 50 to 2000 Hz with sound-pressure levels within the swim bladder about 4 or 5 dB below the sound pressure outside of the fish. 3. Phase measurements in the swim bladder were not significantly different from those made outside of the fish. 4. The data indicate that there is little loss between the water and the inside of the fish, indicating that the swim bladder acts to closely couple the fish to the water. This has significant implications since a poorly coupled system would severely limit detection capabilities for sounds and greatly increase the energy needed to get sound into the water during sound production. 5. The fact that there is a flat response over the major portion of the range of auditory sensitivity in goldfish indicates that the swim bladder is most probably not a limiting factor in acoustic sensitivity, at least below 2000 Hz. In addition, the swim bladder, as a poorly tuned or untuned system, does not selectively affect signals around what would be the resonance frequency in a more sharply tuned system. 6. The poor tuning of the swim bladder is important for communication since a portion of the communicatively significant sounds for fishes are broad-band, rapidly repeating pulses. A sharply tuned system cannot respond to these signals while a poorly tuned system is suitable for wide-band and time-locked reception.

scholarly journals A Reference Spectrum Model for Estimating Source Levels of Marine Shipping Based on Automated Identification System Data

2021 ◽  
Vol 9 (4) ◽  
pp. 369 ◽  
Author(s):  
Alexander MacGillivray ◽  
Christ de Jong
Keyword(s):  
Objective Assessment ◽  
Noise Pollution ◽  
Specific Reference ◽  
Identification System ◽  
Reference Spectrum ◽  
Underwater Sound ◽  
The North ◽  
Joint Monitoring ◽  
Source Level ◽  
Spectrum Model

Underwater sound mapping is increasingly being used as a tool for monitoring and managing noise pollution from shipping in the marine environment. Sound maps typically rely on tracking data from the Automated Information System (AIS), but information available from AIS is limited and not easily related to vessel noise emissions. Thus, robust sound mapping tools not only require accurate models for estimating source levels for large numbers of marine vessels, but also an objective assessment of their uncertainties. As part of the Joint Monitoring Programme for Ambient Noise in the North Sea (JOMOPANS) project, a widely used reference spectrum model (RANDI 3.1) was validated against statistics of monopole ship source level measurements from the Vancouver Fraser Port Authority-led Enhancing Cetacean Habitat and Observation (ECHO) Program. These validation comparisons resulted in a new reference spectrum model (the JOMOPANS-ECHO source level model) that retains the power-law dependence on speed and length but incorporates class-specific reference speeds and new spectrum coefficients. The new reference spectrum model calculates the ship source level spectrum, in decidecade bands, as a function of frequency, speed, length, and AIS ship type. The statistical uncertainty (standard deviation of the deviation between model and measurement) in the predicted source level spectra of the new model is estimated to be 6 dB.

scholarly journals Measurement of Underwater Acoustic Energy Radiated by Single Raindrops

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2687
Author(s):  
Shu Liu ◽  
Qi Li ◽  
Dajing Shang ◽  
Rui Tang ◽  
Qingming Zhang
Keyword(s):  
Ambient Noise ◽  
Sound Pressure ◽  
Tap Water ◽  
Acoustic Energy ◽  
Underwater Sound ◽  
Underwater Noise ◽  
Energy Characteristics ◽  
Sound Energy ◽  
Dipole Radiation ◽  
Series Of Experiments

Underwater noise produced by rainfall is an important component of underwater ambient noise. For example, the existence of rainfall noise causes strong disturbances to sonar performance. The underwater noise produced by a single raindrop is the basis of rainfall noise. Therefore, it is necessary to study the associated underwater noise when drops strike the water surface. Previous research focused primarily on the sound pressure and frequency spectrum of underwater noise from single raindrops, but the study on its sound energy is insufficient. The purpose of this paper is to propose a method for predicting the acoustic energy generated by raindrops of any diameter. Here, a formula was derived to calculate the underwater sound energy radiated by single raindrops based on a dipole radiation pattern. A series of experiments were conducted to measure the underwater sound energy in a 15 m × 9 m × 6 m reverberation tank filled with tap water. The analysis of the acoustic energy characteristics and conversion efficiency from kinetic to acoustic energy helped develop the model to predict the average underwater sound energy radiated by single raindrops. Using this model, the total underwater sound energy of all raindrops during a rainfall event can be predicted based on the drop size distribution.

scholarly journals ENGINEERING OF ACOUSTIC TECHNOLOGY FOR UNDERWATER POSITIONING OBJECT

2018 ◽  
Vol 10 (3) ◽  
pp. 629-637
Author(s):  
Billi Rifa Kusumah ◽  
Indra Jaya ◽  
Henry M. Manik ◽  
. Susilohadi
Keyword(s):  
Control System ◽  
Sound Source ◽  
Arrival Time ◽  
Equation Model ◽  
Control Device ◽  
Electromagnetic Signal ◽  
Positioning System ◽  
Underwater Sound ◽  
Underwater Positioning ◽  
The Difference

Underwater Positioning System (UPS) is a system to track the existence of the position of an object by utilizing the arrival time of the signal measurement. On land, the system uses an electromagnetic signal called GPS. However, because it cannot penetrate water effectively, an acoustic signal is used as an alternative. The purpose of this research is to engineer the control system of data acquisition and underwater acoustic device to measure arrival time (TOA) and apply equation model for underwater sound source positioning system. the effective frequency resonance of the transducer and the hydrophone is at a frequency of 6 kHz. The acquisition control device is able to measure the TOA signal with an error on a digital channel smaller than an analog channel. The difference between the TOA values measured by oscilloscope and acquisition control system is caused by inaccuracy of threshold estimates at the receiver's peak detector circuit. The position of the sound source coordinates obtained from the equation model shows the highest difference in depth point (z) compared to points (x) and (y), caused by the equation model used is limited to four hydrophone units forming a horizontal baseline.

An Indication of Underwater Sound Production by Squid

Nature ◽  
1963 ◽  
Vol 199 (4890) ◽  
pp. 250-251 ◽  
Author(s):  
ROBERT T. S. IVERSEN ◽  
PAUL J. PERKINS ◽  
Richard D. Dionne
Keyword(s):  
Sound Production ◽  
Underwater Sound

Evaluation of Reflectance Fluorodensitometry for Measuring Aflatoxins on Thin Layer Plates

1971 ◽  
Vol 54 (4) ◽  
pp. 870-873
Author(s):  
Walter A Pons
Keyword(s):  
Thin Layer ◽  
Silica Gel ◽  
Uv Light ◽  
Plate Surface ◽  
Coefficients Of Variation ◽  
Standard Application ◽  
Tlc Plates ◽  
Relationship Of ◽  
The Relationship

Abstract A reflectance fluorodensitometer employing illumination of chromatograms with longwave UV light at 45° angles to the plate surface and measurement of reflected fluorescence at 90° was found to be suitable for measuring aflatoxins on silica gel-coated thin layer plates. The relationship of peak area vs. concentration was linear for 1–20 ng aflatoxins B1 and G1/ spot. Degradation of aflatoxins was slight. Five repetitive scans of the same chromatogram containing 5 ng each of B1 and G1 reduced the recorded areas an average of 1% per scan. Consecutive scans of 8 identical standard chromatograms containing 5 ng each of B1 and G1 and 1.5 ng each of B2 and G2 showed a reproducibility, as measured by coefficients of variation, of ±4–5% (B1 and G1) and ±5–9% (B2 and G2), representing the combined errors of standard application, TLC development, and scanning. Analysis of aflatoxins in purified sample extracts from 6 contaminated oilseed meals, 3–500 μg afla toxins/kg, in which the same TLC plates were scanned by a transmission densitometer and the reflectance densitometer yielded essentially equivalent values.

scholarly journals A sciaenid swim bladder with long skinny fingers produces sound with an unusual frequency spectrum

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hin-Kiu Mok ◽  
Shih-Chia Wu ◽  
Soranuth Sirisuary ◽  
Michael L. Fine
Keyword(s):  
Frequency Spectrum ◽  
Fundamental Frequency ◽  
Pulse Repetition Rate ◽  
Sound Production ◽  
Swim Bladder ◽  
Low Frequencies ◽  
Pass Filter ◽  
Number Of Cycles ◽  
Almost All ◽  
High Pass

Abstract Swim bladders in sciaenid fishes function in hearing in some and sound production in almost all species. Sciaenid swim bladders vary from simple carrot-shaped to two-chambered to possessing various diverticula. Diverticula that terminate close to the ears improve hearing. Other unusual diverticula heading in a caudal direction have not been studied. The fresh-water Asian species Boesemania microlepis has an unusual swim bladder with a slightly restricted anterior region and 6 long-slender caudally-directed diverticula bilaterally. We hypothesized that these diverticula modify sound spectra. Evening advertisement calls consist of a series of multicycle tonal pulses, but the fundamental frequency and first several harmonics are missing or attenuated, and peak frequencies are high, varying between < 1–2 kHz. The fundamental frequency is reflected in the pulse repetition rate and in ripples on the frequency spectrum but not in the number of cycles within a pulse. We suggest that diverticula function as Helmholz absorbers turning the swim bladder into a high-pass filter responsible for the absence of low frequencies typically present in sciaenid calls. Further, we hypothesize that the multicycle pulses are driven by the stretched aponeuroses (flat tendons that connect the sonic muscles to the swim bladder) in this and other sciaenids.

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