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

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.

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Multifrequency target strength of northern krill (Meganyctiphanes norvegica) swimming horizontally

ICES Journal of Marine Science ◽

10.1093/icesjms/fsr170 ◽

2011 ◽

Vol 69 (1) ◽

pp. 119-130 ◽

Cited By ~ 5

Author(s):

Lucio Calise ◽

Tor Knutsen

Keyword(s):

Length Distribution ◽

Ex Situ ◽

Target Strength ◽

Acoustic Backscatter ◽

Acoustic Measurements ◽

Acoustic Beams ◽

Meganyctiphanes Norvegica ◽

Acoustic Identification ◽

Made In

Abstract Calise, L., and Knutsen, T. 2012. Multifrequency target strength of northern krill (Meganyctiphanes norvegica) swimming horizontally. – ICES Journal of Marine Science, 69: 119–130. Multifrequency acoustic measurements on ex situ horizontally swimming krill were made in a novel experimental setting. An ensemble of northern krill (Meganyctiphanes norvegica) was introduced to a large enclosure (a mesocosm), and acoustic backscatter was sampled using a multifrequency (70, 120, and 200 kHz) echosounder (Simrad EK60). Two submerged lamps were placed at opposite sides of the mesocosm and switched on and off to induce the krill, by light attraction, to swim horizontally through the acoustic beams. By tracking echoes, animal displacement, swimming speed, and target strength (TS) by frequency were estimated. The dominant and secondary modes of the total-length distribution were 21.8 ± 3.0 and 27.8 ± 2.7 mm, respectively. Although krill orientation was assumed stable and the ping rate was high, the range and inter-ping variability of the average TS values were large, decreasing and increasing with frequency, respectively. The overall TS frequency response observed and concurrent measurements at 120 and 200 kHz confirm the theoretical expectation that the acoustic backscatter from the investigated organisms were confined to the Rayleigh and Geometric scattering regions, a finding that might both aid acoustic identification and size-group separation of in situ northern krill.

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The relative frequency response derived from individually separated targets of northeast Arctic cod (Gadus morhua), saithe (Pollachius virens), and Norway pout (Trisopterus esmarkii)

ICES Journal of Marine Science ◽

10.1093/icesjms/fsp070 ◽

2009 ◽

Vol 66 (6) ◽

pp. 1149-1154 ◽

Cited By ~ 9

Author(s):

Geir Pedersen ◽

Rolf J. Korneliussen

Keyword(s):

Frequency Response ◽

Relative Frequency ◽

Gadus Morhua ◽

Target Strength ◽

Reference Frequency ◽

Acoustic Measurements ◽

Arctic Cod ◽

High Frequencies ◽

Specific Frequency

Abstract Pedersen, G., and Korneliussen, R. J. 2009. The relative frequency response derived from individually separated targets of northeast Arctic cod (Gadus morhua), saithe (Pollachius virens), and Norway pout (Trisopterus esmarkii). – ICES Journal of Marine Science, 66: 1149–1154. The concept of relative frequency response r(f) of fish is an important feature used to characterize acoustic targets. It is defined as the volume-backscattering coefficient at a specific frequency f relative to that of a reference frequency. When based on volume backscattering, r(f) reliably distinguishes several acoustic categories if the insonified volumes are reasonably comparable between the frequencies, and that enough samples and targets are measured to constrain stochastic variations in the data within acceptable limits. Therefore, r(f) distinguishes different fish species with swimbladders poorly if they appear as single targets. Using target-strength (TS) data, the acoustic measurements are more spatially comparable, and averaging the TS over an echotrace of a single fish improves the ability to distinguish between different species. Frequency response was estimated using TS data from in situ measurements, collected using Simrad EK60 echosounders with split-beam transducers transmitting simultaneously at 18, 38, 70, 120, and 200 kHz. Selected series with nearly pure catches of northeast Arctic cod (Gadus morhua), saithe (Pollachius virens), and Norway pout (Trisopterus esmarkii) were analysed using a target-tracking algorithm. The frequency response of northeast Arctic cod and saithe did not differ significantly, but at high frequencies, the response of both northeast Arctic cod and saithe differed from that of Norway pout. However, in the latter case, northeast Arctic cod and saithe could be separated, because of their different TS magnitudes.

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Estimating target strength and physical characteristics of gas-bearing mesopelagic fish from wideband in situ echoes using a viscous-elastic scattering model

The Journal of the Acoustical Society of America ◽

10.1121/10.0003341 ◽

2021 ◽

Vol 149 (1) ◽

pp. 673-691

Author(s):

Babak Khodabandeloo ◽

Mette Dalgaard Agersted ◽

Thor Klevjer ◽

Gavin J. Macaulay ◽

Webjørn Melle

Keyword(s):

Elastic Scattering ◽

Physical Characteristics ◽

Target Strength ◽

Mesopelagic Fish ◽

Scattering Model ◽

Gas Bearing

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Influence of protein (human galectin-3) design on aspects of lectin activity

Histochemistry and Cell Biology ◽

10.1007/s00418-020-01859-9 ◽

2020 ◽

Vol 154 (2) ◽

pp. 135-153 ◽

Cited By ~ 1

Author(s):

Gabriel García Caballero ◽

Donella Beckwith ◽

Nadezhda V. Shilova ◽

Adele Gabba ◽

Tanja J. Kutzner ◽

...

Keyword(s):

Protein Design ◽

Full Range ◽

Biological Information ◽

The Novel ◽

Modular Assembly ◽

Binding Partners ◽

Galectin 3 ◽

Potential Applications ◽

Similar Affinity

Abstract The concept of biomedical significance of the functional pairing between tissue lectins and their glycoconjugate counterreceptors has reached the mainstream of research on the flow of biological information. A major challenge now is to identify the principles of structure–activity relationships that underlie specificity of recognition and the ensuing post-binding processes. Toward this end, we focus on a distinct feature on the side of the lectin, i.e. its architecture to present the carbohydrate recognition domain (CRD). Working with a multifunctional human lectin, i.e. galectin-3, as model, its CRD is used in protein engineering to build variants with different modular assembly. Hereby, it becomes possible to compare activity features of the natural design, i.e. CRD attached to an N-terminal tail, with those of homo- and heterodimers and the tail-free protein. Thermodynamics of binding disaccharides proved full activity of all proteins at very similar affinity. The following glycan array testing revealed maintained preferential contact formation with N-acetyllactosamine oligomers and histo-blood group ABH epitopes irrespective of variant design. The study of carbohydrate-inhibitable binding of the test panel disclosed up to qualitative cell-type-dependent differences in sections of fixed murine epididymis and especially jejunum. By probing topological aspects of binding, the susceptibility to inhibition by a tetravalent glycocluster was markedly different for the wild-type vs the homodimeric variant proteins. The results teach the salient lesson that protein design matters: the type of CRD presentation can have a profound bearing on whether basically suited oligosaccharides, which for example tested positively in an array, will become binding partners in situ. When lectin-glycoconjugate aggregates (lattices) are formed, their structural organization will depend on this parameter. Further testing (ga)lectin variants will thus be instrumental (i) to define the full range of impact of altering protein assembly and (ii) to explain why certain types of design have been favored during the course of evolution, besides opening biomedical perspectives for potential applications of the novel galectin forms.

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