Fish density and target strength distribution of single fish echoes in varying light conditions with single and split beam echosounding and trawling

Jurvelius, Juha; Marjomäki, Timo J.; Peltonen, Heikki; Degtev, A. I.; Bergstrand, Eva; Enderlein, O.; Auvinen, Heikki

doi:10.1007/s10750-016-2780-0

Cited by 5 publications

(6 citation statements)

References 19 publications

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“…Daytime was chosen because the fish are distributed on greater depth than at night [12,13], so a higher number of fish will be detected (in the approximately coned sound beam) at daytime, giving a more representative TS distribution. Jurvelius et al [10] recommended recording in darkness when recording echoes of TS < −44 dB, (i.e., fish length < 15 cm), at high densities (> 1000 fish per ha), due to schooling behavior during daylight. In Lake Storsjøen, density was lower (< 1000 fish per ha), and the fish larger (30-40% of the echoes had TS ≥ −44 dB).…”

Section: Methodsmentioning

confidence: 99%

“…Historical hydroacoustic data, recorded by means of older equipment are important for comparison with current and future surveys in a climate change perspective, and there is a need for calibration of old to new equipment. A few comparative studies are published, like a comparison of the single beam Simrad EY-M with the split beam Simrad EY200 [9] and with the Simrad EY500 with both single and split beam transducers [10]. The Simrad EY-M could serve as a common reference.…”

Section: Introductionmentioning

confidence: 99%

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Comparing Fish Density and Echo Strength Distribution Recorded by Two Generations of Single Beam Echo Sounders

et al. 2019

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Hydroacoustic acquisition was performed by means of two different single beam systems, the Simradmodel EK15 from 2015 and the Simrad model EY-M from the 1980s to explore potential differences of fish density and target strength (TS) distribution between EK15 and EY-M-based estimates. The oligotrophic Lake Storsjøen (48 km2) with steep shores, was chosen for the survey. The pelagic fish stock is dominated by whitefish (Coregonus lavaretus L.), and, recently, illegally stocked smelt (Osmerus eperlanus L.), and a low proportion of Arctic charr (Salvelinus alpinus L.). The total density was estimated at two depth layers (18–32 and 32–48 m), and was quite similar for TS ≥ −56 dB: 755 and 498 fish ha−1, respectively for the EK15-based estimates and similarly 766 and 490 fish ha−1 for the EY-M estimate. Target strength distributions were similar for TS > −48 dB. The proportion of single fish detected with EK15 was negatively affected by the long pulse duration. Six acquisitions from 1986 to 2016 showed a dramatic increase of density of TS = −46 to −44 dB echoes (>10 cm) between 2013 and 2016. This was due to the growth of the introduced smelt population.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparing Fish Density and Echo Strength Distribution Recorded by Two Generations of Single Beam Echo Sounders

et al. 2019

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“…To date research on fish stock estimates done by cruise track using a SIMRAD EK 60 Scientific split beam echosounder system with a frequency of 70kHz and acoustic data acquisition is performed continuously during the day and night during the period boat cruise at speeds ranging between 7-8 knots. Trails include a data acquisition area of an area that allows the analysis of spatially made with zig-zag shape according to [6,26,27] with the length of each transect approximately 1nmi of bounds islands outwards. Density values for fish processing performed on Ms. Excel.…”

Section: Fish Density (Abundance Fish)mentioning

confidence: 99%

Acoustic Systems (Split Beam Echo Sounder) to Determine Abundance of Fish in Marine Fisheries

Lubis¹

2017

OFOAJ

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Acoustic waves are transmitted into the subsurface ocean will experience (scattering) caused by marine organisms, material distributed in the ocean, the structure is not homogeneous in seawater, as well as reflections from the surface and the seabed. Estimation of fish stocks in the waters wide as in Indonesia have a lot of them are using the acoustic method. Acoustic method has high speed in predicting the size of fish stocks so as to allow acquiring data in real time, accurate and high speed so as to contribute fairly high for the provision of data and information of fishery resources. Split beam echo sounder comprises two aspects, and a transducer. First aspect is the high-resolution color display for displaying echogram at some observations and also serves as a controller in the operation of the echo sounder. The second aspect is tranciever consisting of transmitter and receiver. Echosunder divided bim first inserted into the ES 3800 by SIMRAD beginning of the 1980s and in 1985 was introduced to fishermen in Japan as a tool for catching up. Split beam transducer is divided into four quadrants. Factors that contribute affect the value of Target Strength (TS) fish Strength targer can generally be influenced by three factors: a target factor itself, environmental factors, and factors acoustic instrument. Factors include the size of the target, the anatomy of fish, swim bladder, the behavior of orientation.

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“…Acoustic detection technology based on scientific echosounders is widely used in the field of fishery resource investigation [1][2][3][4][5][6][7][8][9]. This type of echosounder performs vertical or horizontal detection underwater by transmitting and receiving acoustic waves [1].…”

Section: Introductionmentioning

confidence: 99%

Broadband Scattering Characteristic Quantization Technique for Single Fish Based on a Split-Beam Echosounder

Ai,

Li,

Yao

et al. 2023

Fishes

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The utilization of broadband quantization data increases the possibility of practical applications for fish target recognition based on the acoustic scattering theory. However, the quantification of broadband data is more complex than that of narrowband systems, requiring consideration of the broadband characteristics of split-beam transducers, seawater absorption, and circuits. This paper elucidates the scatterer acoustic field equation, transducer power equation, and signal processing flow in split-beam broadband quantization technology for engineering applications. A broadband calculation model based on transducer parameters is proposed to enhance the generalization ability of broadband quantization technology to different types of sonar. The classical echo integration method is combined with Fourier transform to meet the requirements of target strength (TS) estimation under broadband signals. This paper includes a series of experiments to prove the rationality and effectiveness of the method. The results demonstrate that the provided calculation model can more accurately reflect the backscattering characteristics of the scatterer, but certain errors remain. This article analyzes the sources of errors and validates the effectiveness of the new TS calculation method.

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Fish density and target strength distribution of single fish echoes in varying light conditions with single and split beam echosounding and trawling

Cited by 5 publications

References 19 publications

Comparing Fish Density and Echo Strength Distribution Recorded by Two Generations of Single Beam Echo Sounders

Comparing Fish Density and Echo Strength Distribution Recorded by Two Generations of Single Beam Echo Sounders

Acoustic Systems (Split Beam Echo Sounder) to Determine Abundance of Fish in Marine Fisheries

Broadband Scattering Characteristic Quantization Technique for Single Fish Based on a Split-Beam Echosounder

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