scholarly journals Swimbladder Morphology and Target Strength of a Mesopelagic Fish, Maurolicus japonicus

2009 ◽  
Vol 36 (4) ◽  
pp. 241-249 ◽  
Author(s):  
Tadanori FUJINO ◽  
Kazuhiro SADAYASU ◽  
Koki ABE ◽  
Hideaki KIDOKORO ◽  
Yongjun TIAN ◽  
...  
Keyword(s):  
Target Strength ◽  
Mesopelagic Fish

scholarly journals Target Strength and swimbladder morphology of Mueller’s pearlside (Maurolicus muelleri)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
B. Sobradillo ◽  
G. Boyra ◽  
U. Martinez ◽  
P. Carrera ◽  
M. Peña ◽  
...  
Keyword(s):  
Relevant Information ◽  
Target Strength ◽  
Fish Length ◽  
Mesopelagic Fish ◽  
Bay Of Biscay ◽  
Numerical Abundance ◽  
Density Filter ◽  
Pressure Changes ◽  
First Time ◽  
Best Fit

AbstractIn the last few years, there has been increasing interest in the commercial exploitation of mesopelagic fish and a trawl-acoustic methodology has been recommended to make estimates of abundance of these resources. This study provides relevant information on the scattering properties of a key mesopelagic fish species in the Bay of Biscay, Mueller’s pearlside (Maurolicus muelleri), necessary to convert the acoustic density into numerical abundance. The target strength (TS) of pearlside was estimated for the first time at five frequencies commonly used in acoustic surveys. A high-density filter was applied to reduce the bias derived from overlapping echoes erroneously assigned to single targets. Its relationship with fish length (b20) was also determined (−65.9 ± 2, −69.2 ± 3, −69.2 ± 2, −69.5 ± 2.5 and −71.5 ± 2.5 dB at 18, 38, 70, 120 and 200 kHz, respectively). Biomass estimates of pearlside in the Bay of Biscay during the four years of study (2014–2017) are given using the 38 kHz frequency. Morphological measurements of the swimbladder were obtained from soft X-ray images and used in the backscattering simulation of a gas-filled ellipsoid. Pearlside is a physoclist species, which means that they can compensate the swimbadder volume against pressure changes. However, the best fit between the model and the experimental data showed that they lose that capacity during the trawling process, when the swimbladder volume is affected by Boyle’s law.

scholarly journals Mesopelagic flesh shear viscosity estimation from in situ broadband backscattering measurements by a viscous–elastic model inversion

2021 ◽  
Author(s):  
Babak Khodabandeloo ◽  
Mette Dalgaard Agersted ◽  
Thor A Klevjer ◽  
Geir Pedersen ◽  
Webjørn Melle
Keyword(s):  
Shear Viscosity ◽  
Spherical Model ◽  
Biological Information ◽  
Target Strength ◽  
Mesopelagic Fish ◽  
Elastic Model ◽  
Acoustic Measurements ◽  
Model Inversion ◽  
Fish Flesh

Abstract In fisheries acoustics, target strength (TS) is a key parameter in converting acoustic measurements to biological information such as biomass. Modelling is a versatile tool to estimate TS of marine organisms. For swimbladdered fish, flesh shear viscosity is one of the required parameters to correctly calculate TS around the resonance frequency, where the target scatters most strongly. Resonance of mesopelagic swimbladdered fish can occur over a range of frequencies and can be within commonly used frequencies (e.g. 18, 38, or 70 kHz). Since there is little information on flesh shear viscosity of fish, especially for mesopelagic species, their resonance can bias the biological information extracted from acoustic measurements. Here, first, the applicability of using a spherical model to estimate resonant backscattering of a generic swimbladder is investigated. Subsequently, a viscous–elastic spherical gas backscattering model is used to estimate the flesh shear viscosity of swimbladdered mesopelagic fish (most likely Cyclothone spp., Family: Gonostomatidae) from in situ broadband backscattering measurements. Finally, the effects of flesh shear viscosity on the TS of swimbladdered mesopelagic fish at 18, 38 (a widely used channel to study mesopelagic layers), and 70 kHz are examined.

scholarly journals Target strength of the lanternfish, Stenobrachius leucopsarus (family Myctophidae), a fish without an airbladder, measured in the Bering Sea

2006 ◽  
Vol 63 (4) ◽  
pp. 683-692 ◽  
Author(s):  
Hiroki Yasuma ◽  
Yoshimi Takao ◽  
Kouichi Sawada ◽  
Kazushi Miyashita ◽  
Ichiro Aoki
Keyword(s):  
Mass Density ◽  
Prolate Spheroid ◽  
Target Strength ◽  
Relative Mass ◽  
Mesopelagic Fish ◽  
Small Fish ◽  
Horizontal Orientation ◽  
Highly Sensitive ◽  
Slender Bodies ◽  
Good Agreement

Abstract This paper reports theoretical values of target strength (TS) for the lanternfish Stenobrachius leucopsarus, a fish without an airbladder, which dominates the Subarctic marine mesopelagic fish community. Two models for liquid-like slender bodies, the general prolate-spheroid model (PSM) and the deformed-cylinder model (DCM), were used to compute the TS of the fish relative to its orientation. The relative mass density g and the sound speed h in seawater were measured and used in both models. To confirm the appropriateness of the models, tethered experimental measurements were carried out at 38 kHz for five specimens. The value of g measured by the density-bottle method was very low (1.002–1.009) compared with that of marine fish in general. The value of h measured by the time-average approach was 1.032–1.039 at the water temperature at which S. leucopsarus is found. TS-fluctuation patterns against fish orientation (the TS pattern) estimated from the DCM and PSM were in good agreement in the area of their main lobes. Both models reproduced the main lobes of the measured TS patterns in near-horizontal orientation (<±20°), and they were considered to be effective in measuring the TS of S. leucopsarus in a horizontal (swimming) position. After these comparative experiments, we computed the TS of 57 fish (27.8–106.9 mm) at 38, 70, 120, and 200 kHz, using the DCM. A plot of body length (in log scale) against TS showed a non-linear relationship at all frequencies. S. leucopsarus had a very low TS (<−85 dB, TScm), suggesting that acoustic assessment would be highly sensitive, especially when the proportion of small fish is high (e.g. L/λ < 2), and an appropriate frequency should be considered that takes into account both the length composition and the depth of occurrence.

Target strength of a mesopelagic fish Maurolicus japonicus at 38 and 120 kHz

2006 ◽  
Vol 120 (5) ◽  
pp. 3107-3107
Author(s):  
Tadanori Fujino ◽  
Hiroki Yasuma ◽  
Kazushi Miyashita ◽  
Kazuhiro Sadayasu ◽  
Koki Abe
Keyword(s):  
Target Strength ◽  
Mesopelagic Fish

Size, peripheral auditory tuning and target strength in noctuid moths

2000 ◽  
Vol 25 (4) ◽  
pp. 346-353 ◽  
Author(s):  
Alex P. Norman ◽  
Gareth Jones
Keyword(s):  
Target Strength

QUANTIFICATION OF TUNA FISH TARGET STRENGTH USING QUANTITATIVE ECHO SOUNDER

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Henry M. Manik
Keyword(s):  
Wave Reflection ◽  
Fork Length ◽  
Research Programme ◽  
Yellowfin Tuna ◽  
Target Strength ◽  
Bigeye Tuna ◽  
Tuna Fish ◽  
Thunnus Obesus ◽  
The Relationship ◽  
Echo Sounder

A preliminary research programme was carried out in order to study the acoustic wave reflection or target strength (TS) of tuna fish using a quantitative echo sounder (QES). The relationships between TS to fork length (FL) and swimbladder volume, for bigeye tuna (Thunnus obesus) and yellowfin tuna (T. albacares) are investigated. The TS of bigeye tuna was about 3 dB higher than yellowfin tuna when comparing species at the same size. The result can be correlated to the swimbladder volume differencebetween species. The relationship between TS and swimbladder volume was quantified for both species.Keywords: tuna fish, target strength, quantitative echo sounder

Oceanographic influences on the early life stages of a mesopelagic fish across the Chilean Patagonia

2021 ◽  
Vol 195 ◽  
pp. 102572
Author(s):  
Víctor Molina-Valdivia ◽  
Claudia A. Bustos ◽  
Manuel I. Castillo ◽  
Francesca V. Search ◽  
Guido Plaza ◽  
...  
Keyword(s):  
Early Life ◽  
Mesopelagic Fish ◽  
Life Stages ◽  
Early Life Stages ◽  
Chilean Patagonia
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